Race, ethnicity, and genomics: social classifications as proxies of biological heterogeneity

The role of ethnicity and native-country income in multiple sclerosis: the Italian multicentre study (MS-MigIT)

OBJECTIVE

Multiple sclerosis (MS) is a complex disorder in which environmental and genetic factors interact modifying disease risk and course. This multicentre, case-control study involving 18 Italian MS Centres investigated MS course by ethnicity and native-country economic status in foreign-born patients living in Italy.

METHODS

We identified 457 MS patients who migrated to Italy and 893 age- and sex-matched native-born Italian patients. In our population, 1225 (93.2%) subjects were White Europeans and White Northern Americans (WENA) and 89 (6.8%) patients were from other ethnical groups (OEG); 1109 (82.1%) patients were born in a high-income (HI) Country and 241 (17.9%) in a low-middle-income (LMI) Country. Medical records and patients interviews were used to collect demographic and disease data.

RESULTS

We included 1350 individuals (973 women and 377 men); mean (SD) age was 45.0 (11.7) years. At onset, 25.45% OEG patients vs 12.47% WENA (p = 0.039) had > 3 STIR spine lesions. At recruitment, the same group featured mean (SD) EDSS score of 2.85 (2.23) vs 2.64 (2.28) (p = 0.044) reached in 8.9 (9.0) vs 12.0 (9.0) years (p = 0.018) and underwent 1.10 (4.44) vs. 0.99 (0.40) annual MRI examinations (p = 0.035). At disease onset, patients from LMI countries had higher EDSS score than HI patients (2.40 (1.43) vs 1.99 (1.17); p = 0.032).

DISCUSSION

Our results suggested that both ethnicity and socio-economic status of native country shape MS presentation and course and should be considered for an appropriate management of patients. To the best of our knowledge, this is the first study reporting on the impact of ethnicity in MS at an individual level and beyond an ecological population-perspective.

Optimal strategies for learning multi-ancestry polygenic scores vary across traits

Polygenic scores (PGSs) are individual-level measures that aggregate the genome-wide genetic predisposition to a given trait. As PGS have predominantly been developed using European-ancestry samples, trait prediction using such European ancestry-derived PGS is less accurate in non-European ancestry individuals. Although there has been recent progress in combining multiple PGS trained on distinct populations, the problem of how to maximize performance given a multiple-ancestry cohort is largely unexplored. Here, we investigate the effect of sample size and ancestry composition on PGS performance for fifteen traits in UK Biobank. For some traits, PGS estimated using a relatively small African-ancestry training set outperformed, on an African-ancestry test set, PGS estimated using a much larger European-ancestry only training set. We observe similar, but not identical, results when considering other minority-ancestry groups within UK Biobank. Our results emphasise the importance of targeted data collection from underrepresented groups in order to address existing disparities in PGS performance.

Facing Our History-Building an Equitable Future

This report is the product of a major year-long initiative to acknowledge and reckon with past injustice, as well as progress toward justice, within the American Society of Human Genetics (ASHG) and the broader field of human genetics. Approved by the ASHG Board of Directors and launched in 2021, the initiative was sparked by the social and racial reckonings in 2020. The ASHG Bboard of Directors asked ASHG to acknowledge and provide examples of how human genetics theories and knowledge "have been used to feed and justify racism, eugenics, and other systemic forms of injustice, and to focus specifically on examples of ASHG's role in fostering or failing to rebuke harms and on steps the Society could take to address findings." The initiative was undertaken with support and input from an expert panel of human geneticists, historians, clinician-scientists, equity scholars, and social scientists and included a research and environmental scan, four expert panel meetings, and a community dialogue as its main activities.

A scoping review of guidelines for the use of race, ethnicity, and ancestry reveals widespread consensus but also points of ongoing disagreement

The use of population descriptors such as race, ethnicity, and ancestry in science, medicine, and public health has a long, complicated, and at times dark history, particularly for genetics, given the field's perceived importance for understanding between-group differences. The historical and potential harms that come with irresponsible use of these categories suggests a clear need for definitive guidance about when and how they can be used appropriately. However, while many prior authors have provided such guidance, no established consensus exists, and the extant literature has not been examined for implied consensus and sources of disagreement. Here, we present the results of a scoping review of published normative recommendations regarding the use of population categories, particularly in genetics research. Following PRISMA guidelines, we extracted recommendations from n = 121 articles matching inclusion criteria. Articles were published consistently throughout the time period examined and in a broad range of journals, demonstrating an ongoing and interdisciplinary perceived need for guidance. Examined recommendations fall under one of eight themes identified during analysis. Seven are characterized by broad agreement across articles; one, "appropriate definitions of population categories and contexts for use," revealed substantial fundamental disagreement among articles. Additionally, while many articles focus on the inappropriate use of race, none fundamentally problematize ancestry. This work can be a resource to researchers looking for normative guidance on the use of population descriptors and can orient authors of future guidelines to this complex field, thereby contributing to the development of more effective future guidelines for genetics research.

Collecting, Using, and Reporting Race and Ethnicity Information: Implications for Research in Nutrition Education, Practice, and Policy to Promote Health Equity

This report will describe approaches for collecting, analyzing, and reporting race and ethnicity information in nutrition education and behavior research, practice, and policy to advance health equity. Race and ethnicity information is used to describe study participants and compare nutrition and health-related outcomes. Depending on the study design, race and ethnicity categories are often defined by the research question or other standardized approaches. Participant self-reported data are more acceptable than researcher adjudicated identification data, which can add bias and/or error. Valid methods to collect, use, and report race and ethnicity information are foundational to publication quality, findings of value, contribution to the knowledge base, and health equity.

Disparities at the Intersection of Race and Ethnicity: Examining Trends and Outcomes in Hispanic Women With Breast Cancer

PURPOSE

We sought to examine tumor subtype, stage at diagnosis, time to surgery (TTS), and overall survival (OS) among Hispanic patients of different races and among Hispanic and non-Hispanic (NH) women of the same race.

METHODS

Women 18 years of age or older who had been diagnosed with stage 0-IV breast cancer and who had undergone lumpectomy or mastectomy were identified in the National Cancer Database (2004-2014). Tumor subtype and stage at diagnosis were compared by race/ethnicity. Multivariable linear regression and Cox proportional hazards modeling were used to estimate associations between race/ethnicity and adjusted TTS and OS, respectively.

RESULTS

A total of 44,374 Hispanic (American Indian [AI]: 79 [0.2%]; Black: 1,011 [2.3%]; White: 41,126 [92.7%]; Other: 2,158 [4.9%]) and 858,634 NH women (AI: 2,319 [0.3%]; Black: 97,206 [11.3%]; White: 727,270 [84.7%]; Other: 31,839 [3.7%]) were included. Hispanic Black women had lower rates of triple-negative disease (16.2%) than did NH Black women (23.5%) but higher rates than did Hispanic White women (13.9%; P < .001). Hispanic White women had higher rates of node-positive disease (23.2%) versus NH White women (14.4%) but slightly lower rates than Hispanic (24.6%) and NH Black women (24.5%; P < .001). Hispanic White women had longer TTS versus NH White women regardless of treatment sequence (adjusted means: adjuvant chemotherapy, 42.71 v 38.60 days; neoadjuvant chemotherapy, 208.55 v 201.14 days; both P < .001), but there were no significant racial differences in TTS among Hispanic patients. After adjustment, Hispanic White women (hazard ratio, 0.77 [95% CI, 0.74 to 0.81]) and Black women (hazard ratio, 0.75 [95% CI, 0.58 to 0.96]) had improved OS versus NH White women (reference) and Black women (hazard ratio, 1.15 [95% CI, 1.12 to 1.18]; all P < .05).

CONCLUSION

Hispanic women had improved OS versus NH women, but racial differences in tumor subtype and nodal stage among Hispanic women highlight the importance of disaggregating racial/ethnic data in breast cancer research.

The 'ethic of knowledge' and responsible science: Responses to genetically motivated racism

This study takes off from the ethical problem that racism grounded in population genetics raises. It is an analysis of four standard scientific responses to the problem of genetically motivated racism, seen in connection with the Human Genome Diversity Project (HGDP): (1) Discriminatory uses of scientific facts and arguments are in principle 'misuses' of scientific data that the researcher cannot be further responsible for. (2) In a strict scientific sense, genomic facts 'disclaim racism', which means that an epistemically correct grasp of genomics should be ethically justified. (3) Ethical difficulties are issues to be 'resolved' by an ethics institution or committee, which will guarantee the ethical quality of the research scrutinized. (4) Although population genetics occasionally may lead to racism, its overall 'value' for humankind justifies its cause as a desirable pursuit. I argue that these typical responses to genetically motivated racism supervene on a principle called the 'ethic of knowledge', which implies that an epistemically correct account has intrinsic ethical value. This principle, and its logically related ideas concerning the ethic of science, effectively avoids a deeper ethical question of responsibility in science from being raised.

Biomarkers as MEDiators of racial disparities in risk factors (BioMedioR): Rationale, study design, and statistical considerations

PURPOSE

Relative to White adults, Black adults have a substantially higher prevalence of hypertension and diabetes, both key risk factors for stroke, cardiovascular disease, cognitive impairment, and dementia. Blood biomarkers have shown promise in identifying contributors to racial disparities in many chronic diseases.

METHODS

We outline the study design and related statistical considerations for a nested cohort study, the Biomarker Mediators of Racial Disparities in Risk Factors (BioMedioR) study, within the 30,239-person biracial REasons for Geographic And Racial Differences in Stroke (REGARDS) study (2003-present). Selected biomarkers will be assessed for contributions to racial disparities in risk factor development over median 9.4 years of follow-up, with initial focus on hypertension, and diabetes. Here we outline study design decisions and statistical considerations for the sampling of 4,400 BioMedioR participants.

RESULTS

The population for biomarker assessment was selected using a random sample study design balanced across race and sex to provide the optimal opportunity to describe association of biomarkers with the development of hypertension and diabetes. Descriptive characteristics of the BioMedioR sample and analytic plans are provided for this nested cohort study.

CONCLUSIONS

This nested biomarker study will examine pathways with the target to help explain racial differences in hypertension and diabetes incidence.

Keeping race at bay: familial DNA research, the ‘Turkish Community,’ and the pragmatics of multiple collectives in investigative practice

In this contribution, we analyze the recently adjudicated Milica van Doorn rape and murder case. In this case, committed in 1992, no suspect could be identified until investigatory actors employed familial DNA searching in 2017. Crucially, familial DNA typing raised the possibility of ethnic and racial stereotyping and profiling, particularly against the background of the first case in which familial DNA typing was used in the Netherlands: the Marianne Vaatstra case, which from the start had been marred by controversy about the ethnicity of the unknown perpetrator. In our analysis, we show how criminal justice actors managed this potential for racialization through strategically mobilizing and carefully managing multiple collectives. Drawing on the notions of multiplicity and non-coherence, we show we do not only empirically trace the situated ethics and pragmatics of familial DNA research in this specific case, but we also develop a theoretical argument on the multiple and non-coherent character of race itself and its attendant ethical, political, and methodological possibilities and obligations.

A study of transposable element-associated structural variations (TASVs) using a de novo-assembled Korean genome

Advances in next-generation sequencing (NGS) technology have made personal genome sequencing possible, and indeed, many individual human genomes have now been sequenced. Comparisons of these individual genomes have revealed substantial genomic differences between human populations as well as between individuals from closely related ethnic groups. Transposable elements (TEs) are known to be one of the major sources of these variations and act through various mechanisms, including de novo insertion, insertion-mediated deletion, and TE–TE recombination-mediated deletion. In this study, we carried out de novo whole-genome sequencing of one Korean individual (KPGP9) via multiple insert-size libraries. The de novo whole-genome assembly resulted in 31,305 scaffolds with a scaffold N50 size of 13.23 Mb. Furthermore, through computational data analysis and experimental verification, we revealed that 182 TE-associated structural variation (TASV) insertions and 89 TASV deletions contributed 64,232 bp in sequence gain and 82,772 bp in sequence loss, respectively, in the KPGP9 genome relative to the hg19 reference genome. We also verified structural differences associated with TASVs by comparative analysis with TASVs in recent genomes (AK1 and TCGA genomes) and reported their details. Here, we constructed a new Korean de novo whole-genome assembly and provide the first study, to our knowledge, focused on the identification of TASVs in an individual Korean genome. Our findings again highlight the role of TEs as a major driver of structural variations in human individual genomes.

A novel strategy for genome analysis offers insights into the distribution and impact on genome variation of transposable elements, DNA sequences that can replicate and relocate themselves at different chromosomal regions. These sequences, also known as ‘jumping genes’, comprise up to 50% of the genome, but it has proven challenging to map them with existing techniques. Seyoung Mun of Dankook University, Cheonan, South Korea, and coworkers have developed a sequencing and computational analysis strategy that allowed them to accurately map transposable elements across the genome of a Korean individual. These data revealed hundreds of insertion and deletion events relative to an existing reference map of the genome, showing significant alterations in the chromosomal structure. The authors speculate that such widespread transposition events could potentially contribute to individual differences in gene expression and risk of disease.

Racial, Ethnic, and Insurance-Based Disparities Upon Initiation of Anti-Vascular Endothelial Growth Factor Therapy for Diabetic Macular Edema in the US

PURPOSE

This study characterizes the association of risk factors including race, ethnicity, and insurance status with presenting visual acuity (VA) and diabetic retinopathy (DR) severity in patients initiating treatment with anti-vascular endothelial growth factor (VEGF) therapy for diabetic macular edema (DME).

DESIGN

Retrospective, cross-sectional study.

PARTICIPANTS

The Academy Intelligent Research in Sight (IRIS) Registry database was queried for patients who initiated anti-VEGF injection treatment for DME between 2012 and 2020 (n = 203 707).

METHODS

Multivariate regression analyses were conducted to understand how race, ethnicity, insurance status, and geographic location were associated with baseline features.

MAIN OUTCOME MEASURES

Visual acuity and DR severity.

RESULTS

Patients on Medicare and private insurance presented with higher baseline VA compared with patients on Medicaid (median of 2.31 and 4.17 greater Early Treatment Diabetic Retinopathy Scale [ETDRS] letters, respectively P < 0.01). White and non-Hispanic patients presented with better VA compared with their counterparts (median of 0.68 and 2.53 greater ETDRS letters, respectively; P < 0.01). Black and Hispanic patients presented with a worse baseline DR severity compared with White and non-Hispanic patients (odds ratio, 1.23 and 1.71, respectively; P < 0.01).

CONCLUSIONS

There are ethnic and insurance-based disparities in VA and disease severity upon initiation of anti-VEGF therapy for DME treatment. Public health initiatives could improve timely initiation of treatment.

Race, genetic admixture and cognitive performance in the Cuban population

BACKGROUND

Population aging will lead to a dramatic increase in dementia prevalence, which will disproportionally affect racial minorities. The presence of racial differences in dementia prevalence has been widely reported in United States, but there are no relevant studies on this topic in low-middle income countries (LMIC).

METHODS

In a cross-sectional survey, 2,944 older Cubans were recruited at a community-based level aimed to identify the effects of self-identified race and genetic admixture on cognitive performance. Dementia diagnosis was established using 10/66 Dementia and DSM-IV criteria. APOE-ε4 genotype was determined in 2,511 (85%) and genetic admixture was completed for all dementia cases and in a randomly selected sample of cognitive healthy participants (218 dementia cases and 367 participants without dementia).

RESULTS

The overall prevalence of dementia was 8.7%, without large or statistically significant differences on dementia prevalence (p=0.12) by self-identified race. Mean cognitive scores were similar across racial groups (p=0.46). After controlling for age, sex and education, greater proportion of African ancestry was not associated with cognitive performance (p=0.17).

CONCLUSIONS

We found no evidence of an independent effect of self-identified race and/or population ancestry on dementia prevalence or cognitive performance. This suggests that observed differences in dementia prevalence among diverse populations may be driven primarily by social determinants of health.

Race, ethnicity, and racism in the nutrition literature: an update for 2020

Social disparities in the US and elsewhere have been terribly highlighted by the current COVID-19 pandemic but also an outbreak of state-sponsored violence. The field of nutrition, like other areas of science, has commonly used 'race' to describe research participants and populations, without the recognition that race is a social, not a biologic, construct. We review the limitations of classifying participants by race, and recommend a series of steps for authors, researchers and policymakers to consider when producing and reading the nutrition literature. We recommend that biomedical researchers, especially those in the field of nutrition, abandon the use of racial categories to explain biologic phenomena but instead rely on a more comprehensive framework of ethnicity; that authors consider not just race and ethnicity but many social determinants of health, including experienced racism; that race and ethnicity not be conflated; that dietary pattern descriptions inform ethnicity descriptions; and that depersonalizating language be avoided.

The Impact of Ancient Genome Studies in Archaeology

The study of ancient genomes has burgeoned at an incredible rate in the last decade. The result is a shift in archaeological narratives, bringing with it a fierce debate on the place of genetics in anthropological research. Archaeogenomics has challenged and scrutinized fundamental themes of anthropological research, including human origins, movement of ancient and modern populations, the role of social organization in shaping material culture, and the relationship between culture, language, and ancestry. Moreover, the discussion has inevitably invoked new debates on indigenous rights, ownership of ancient materials, inclusion in the scientific process, and even the meaning of what it is to be a human. We argue that the broad and seemingly daunting ethical, methodological, and theoretical challenges posed by archaeogenomics, in fact, represent the very cutting edge of social science research. Here, we provide a general review of the field by introducing the contemporary discussion points and summarizing methodological and ethical concerns, while highlighting the exciting possibilities of ancient genome studies in archaeology from an anthropological perspective.

Knowledge and Attitudes About Genetic Testing Among Black and White Women with Breast Cancer

Prior to embarking on a large descriptive evaluation of genetic/racial variations in symptom phenotype, we sought foundational information to determine racial differences in (1) feasibility (consent) and acceptability of collecting genomic samples, (2) genetic literacy, and (3) concerns of genomic research during breast cancer (BC) chemotherapy. Women with early-stage BC undergoing chemotherapy were recruited from an academic, urban breast care center. Information was collected for consent to participate, genetic literacy, and concerns about genetic testing in Black and White women with BC. Fifty-six women were eligible, and 48 were consented (24 Black, 24 White). All participants consented to blood testing. This highly educated sample's mean age was 52.5 + 12.05 (years). Education (years) and genetic knowledge were positively correlated (p = .038). Genetic scores were high, and only one question significantly differed by race. On interview, most participants thought conducting genetic research helped to better understand hereditary disease and/or identify genes that cause disease and stated that they participated in the research to help other people. The majority of participants responded that friends/family would participate in genetic research without concerns, though three Black participants cited mistrust as a possible concern. Overall, there were high levels of genetic knowledge, slightly different between Black and White women. There were no high levels of personal concern regarding genetic testing. Black women reported more concern than White women that friends/family would have hesitations about participating in genetic research. There was general acceptability of blood collection for genetic testing among women with early-stage BC without racial difference.

A Functional Synonymous Variant in PDGFRA Is Associated with Better Survival in Acral Melanoma

Purpose: Polymorphisms of genes in the platelet-derived growth factor (PDGF) signaling pathway have been found to predict cutaneous melanoma (CM) survival, but their clinical effects in acral melanoma (AM) patients have not been explored. The aim of this study was to characterize the functional effect of the tag single-nucleotide polymorphism (SNP) rs2228230:C>T and assess its association with clinical outcomes in AM patients.

Methods: The effect of rs2228230:C>T on mRNA structures and codon usage values were evaluated using in silico analyses. PDGF receptor alpha (PDGFRA) expression vectors with the rs2228230:C or rs2228230:T allele were constructed to evaluate the expression and signaling activity of PDGFRA. The expression of PDGFRA in AM samples was measured using in situ RNAscope hybridization and immunohistochemical staining. The association of the rs2228230 genotype with survival was analyzed in two independent AM cohorts.

Results: In silico analyses indicated that the rs2228230:T allele increases the minimum free energy and reduces synonymous codon usage. The rs2228230:T allele decreased the expression of PDGFRA by reducing the stability of its mRNA and protein as well as the signaling activity of the MAPK and PI3K/AKT pathways. PDGFRA mRNA and protein expression was significantly reduced in AM tissues with the rs2228230:T allele. The progression-free survival and overall survival of AM patients with the rs2228230:T allele were significantly longer than those of patients with the CC genotype.

Conclusion: Our study indicated that rs2228230:T can reduce the expression of PDGFRA and downstream signaling activity and is associated with better survival in AM patients.

The ethics of global psychiatric genomics: Multilayered challenges to integrating genomics in global mental health and disability-A position paper of the Oxford Global Initiative in Neuropsychiatric GenEthics (NeuroGenE)

Psychiatric genomics has the potential to radically improve the prevention and early intervention of serious mental and neurodevelopmental disorders worldwide. However, little work has been done on the ethics of psychiatric genomics-an oversight that could result in poor local uptake, reduced practical/clinical application, and ethical violations in this rapidly developing area of scientific research. As part of the Global Project of the Stanley Center for Psychiatric Research, the Global Initiative in Neuropsychiatric GenEthics (NeuroGenE) based at the University of Oxford aims to embed ethical inquiry within scientific investigation and engage with fundamental ethical questions around a psychiatric genomics approach to mental and neurodevelopmental disorder. This position paper sets out the core aims of the NeuroGenE research programme and explores the importance of a crosscutting research orientation in this field based on multidisciplinary methodologies which can ensure that efforts to translate and apply global psychiatric genomics in public policy and clinical practice are ethically grounded strategies, respectful of different cultures and contexts.

Ethical dangers of facial phenotyping through photography in psychiatric genomics studies

Psychiatric genomics research protocols are increasingly incorporating tools of deep phenotyping to observe and examine phenotypic abnormalities among individuals with neurodevelopmental disorders. In particular, photography and the use of two-dimensional and three-dimensional facial analysis is thought to shed further light on the phenotypic expression of the genes underlying neurodevelopmental disorders, as well as provide potential diagnostic tools for clinicians. In this paper, I argue that the research use of photography to aid facial phenotyping raises deeply fraught issues from an ethical point of view. First, the process of objectification through photographic imagery and facial analysis could potentially worsen the stigmatisation of persons with neurodevelopmental disorders. Second, the use of photography for facial phenotyping has worrying parallels with the historical misuse of photography to advance positive and negative eugenics around race, ethnicity and intellectual disability. The paper recommends ethical caution in the use of photography and facial phenotyping in psychiatric genomics studies exploring neurodevelopmental disorders, outlining certain necessary safeguards, such as a critical awareness of the history of anthropometric photography use among scientists, as well as the exploration of photographic methodologies that could potentially empower individuals with disabilities.

Black African and Latino/a identity correlates with increased plasmablasts in MS

Objective

To determine the influence of self-reported Black African and Latin American identity on peripheral blood antibody-secreting cell (ASC) frequency in the context of relapsing-remitting MS.

Methods

In this cross-sectional study, we recruited 74 subjects with relapsing-remitting MS and 24 age-, and self-reported ethno-ancestral identity-matched healthy donors (HDs) to provide peripheral blood study samples. Subjects with MS were either off therapy at the time of study draw or on monthly natalizumab therapy infusions. Using flow cytometry, we assessed peripheral blood mononuclear cells for antibody-secreting B-cell subsets.

Results

When stratified by self-reported ethno-ancestry, we identified significantly elevated frequencies of circulating plasmablasts among individuals with MS identifying as Black African or Latin American relative to those of Caucasian ancestry. Ethno-ancestry–specific differences in ASC frequency were observed only among individuals with MS. By contrast, this differential was not observed among HDs. ASCs linked with poorer MS prognosis and active disease, including IgM⁺- and class-switched CD138⁺ subsets, were among those significantly increased.

Conclusion

The enhanced peripheral blood plasmablast signature revealed among Black African or Latin American subjects with MS points to distinct underlying mechanisms associated with MS immunopathogenesis. This dysregulation may contribute to the disease disparity experienced by patient populations of Black African or Latin American ethno-ancestry.

Biomarkers in Cardiovascular Disease: The Dilemma of Racial Differences

See Article Hackler et al

Essential(ist) medicine: promoting social explanations for racial variation in biomedical research

Biomedical research has a long and complicated history as a tool of oppression, exemplary of the racial science used to legitimise and maintain racial hierarchies in the USA and abroad. While the explicit racism and racial inferiority supported by this research has dissipated and modern methods of inquiry have increased in sophistication and rigor, contemporary biomedical research continues to essentialise race by distilling racial differences and disparities in health to an underlying, biogenetic source. Focusing on the persistence of essentialism in an era of genomic medicine, this paper examines the deep social origins and social implications of the essentialist viewpoint in biomedicine and how it relates to the broader construction of social and scientific knowledge. Invoking Hacking's 'looping effects' as a useful conceptual tool, I then demonstrate how sociohistorical forces influence scientific and medical research in producing evidence that favours and legitimises a biological construction of race. I extend the looping framework to consider a parallel 'louping' process whereby applying a socially rooted meaning to race in biomedical research results becomes magnified to influence social norms and ideas about race. As many biomedical researchers are motivated by a desire to eliminate racial disparities in outcomes, I argue that greater social acuity allows scientists to avoid individualising and racialising health, challenge preconceived assumptions about the meaning of racial variation in health and medicine and thus promote and strengthen a socioenvironmental focus on how to best improve individuals' and population health. Concluding with a call for structural competency in biomedical research, I suggest that empowering scientists to more freely discuss sociostructural factors in their work allows for the continued use of race in biological and medical research, while social scientists and medical humanities scholars stand to benefit from seeing their work imbued with the cultural authority currently granted to biomedicine.

A Focus Group Study on African American Living Donors’ Treatment Preferences, Sociocultural Factors, and Health Beliefs About Apolipoprotein L1 Genetic Testing

Introduction:

Because apolipoprotein L1 ( APOL1) risk variants may contribute to live donors’ kidney failure postdonation, professional guidelines suggest informing potential donors with African ancestry about the availability of APOL1 genotyping. This study assessed African American (AA) donors’ perceptions of APOL1 genetic testing and how APOL1 may affect ethnic identity.

Methods/Approach:

Four focus groups were conducted with AA donors about their decision-making for and perceptions of APOL1 genetic testing and donation to inform a new culturally targeted educational brochure on APOL1 genetic testing. Qualitative data were analyzed by thematic analysis.

Findings:

Seventeen donors participated (47% participation rate). Four major themes emerged. (1) In hypothetical scenarios, most participants would have undergone APOL1 testing during donor evaluation to make a more informed decision, but many would have still donated. (2) Participants desired information about how having 2 APOL1 risk variants affects the donor’s and the recipient’s health. (3) Participants referred to diversity of genetic ancestry and cultural constructions of racial/ethnic identity to question the population at risk for APOL1 risk variants and recommended that all potential donors undergo genetic testing and receive education about APOL1. (4) Participants worried that out-of-pocket costs would deter APOL1 testing and that APOL1 could become a preexisting condition and discriminate against AAs.

Discussion:

Our findings suggest that AA donors desire APOL1 testing to foster informed consent. Transplant clinicians should be aware of these responses to APOL1 testing and be sensitive to historical issues of distrust and discrimination.

An Interactive Resource to Probe Genetic Diversity and Estimated Ancestry in Cancer Cell Lines

Recent work points to a lack of diversity in genomics studies from genome-wide association studies to somatic (tumor) genome analyses. Yet, population-specific genetic variation has been shown to contribute to health disparities in cancer risk and outcomes. Immortalized cancer cell lines are widely used in cancer research, from mechanistic studies to drug screening. Larger collections of cancer cell lines better represent the genomic heterogeneity found in primary tumors. Yet, the genetic ancestral origin of cancer cell lines is rarely acknowledged and often unknown. Using genome-wide genotyping data from 1,393 cancer cell lines from the Catalogue of Somatic Mutations in Cancer (COSMIC) and Cancer Cell Line Encyclopedia (CCLE), we estimated the genetic ancestral origin for each cell line. Our data indicate that cancer cell line collections are not representative of the diverse ancestry and admixture characterizing human populations. We discuss the implications of genetic ancestry and diversity of cellular models for cancer research and present an interactive tool, Estimated Cell Line Ancestry (ECLA), where ancestry can be visualized with reference populations of the 1000 Genomes Project. Cancer researchers can use this resource to identify cell line models for their studies by taking ancestral origins into consideration.

Racial and Ethnic Differences in Presentation and Outcomes of Hepatocellular Carcinoma

BACKGROUND & AIMS

Racial and ethnic minorities are reported to have higher mortality related to hepatocellular carcinoma (HCC) than non-Hispanic whites. However, it is not clear whether differences in tumor characteristics or liver dysfunction among racial or ethnic groups affect characterization of causes for this disparity. We aimed to characterize racial and ethnic differences in HCC presentation, treatment, and survival.

METHODS

We performed a retrospective study of patients diagnosed with HCC from January 2008 through July 2017 at 2 large health systems in the United States. We used multivariable logistic regression and Cox proportional hazard models to identify factors associated with receipt of curative therapy and overall survival.

RESULTS

Among 1117 patients with HCC (35.9% white, 34.3% black, 29.7% Hispanic), 463 (41.5%) were diagnosed with early stage HCC (Barcelona Clinic Liver Cancer stage 0/A) and 322 (28.8%) underwent curative treatment. Hispanic (odds ratio [OR], 0.75; 95% CI, 0.55-1.00) and black patients (OR, 0.74; 95% CI, 0.56-0.98) were less likely to be diagnosed with early stage HCC than white patients. Among patients with early stage HCC, Hispanics were less likely to undergo curative treatment than whites (OR, 0.58; 95% CI, 0.36-0.91). Black patients with early stage HCC were also less likely to undergo curative treatment than white patients, but this difference was not statistically significant (OR, 0.66; 95% CI, 0.43-1.03). Black and Hispanic patients had shorter median survival times than white patients (10.6 and 14.4 mo vs 16.3 mo). After adjusting for type of medical insurance, Child-Pugh class, Barcelona Clinic Liver Cancer stage, and receipt of HCC treatment, black patients had significantly higher mortality (hazard ratio, 1.12; 95% CI, 1.10-1.14) and Hispanic patients had lower mortality (hazard ratio, 0.83; 95% CI, 0.74-0.94) than white patients.

CONCLUSIONS

In a retrospective study of patients diagnosed with HCC, we found racial/ethnic differences in outcomes of HCC to be associated with differences in detection of tumors at early stages and receipt of curative treatment. These factors are intervention targets for improving patient outcomes and reducing disparities.

Genetic polymorphisms in very important pharmacogenomic variants in the Zhuang ethnic group of Southwestern China: A cohort study in the Zhuang population

Pharmacogenomics, the study of the role of genetics in drug response, has recently become a focal point of research. Previous studies showed that genes associated with drug detoxification vary among different populations. However, pharmacogenomic information of the Zhuang ethnic group is scarce. The aim of the present study was to screen members of the Zhuang ethnicity in southwestern China for genotype frequencies of very important pharmacogenomic (VIP) variants and to determine the differences between the Zhuang ethnicity and other human populations.We genotyped 80 variants of VIP genes in 100 unrelated healthy Zhuang adults from the Yunnan province of China. Next, we analyzed the genotyping data with Structure and F-statistics (Fst).We compared our data with those of other populations using the HapMap data set, and observed that the frequency distribution of Zhuang population in Yunnan closely resembles that of JPT. Furthermore, population structure and Fst analysis showed that the Zhuang population is closely related to the Shaanxi Han population with respect to genetic background.Our study supplements existing information on Zhuang population pharmacogenomics and provides an extensive overview for developing personalized medicine.

The role of race in clinical decision making

Is race/ethnicity useful in clinical decision making? This article uses a case example to discuss the role of race/ethnicity in clinical decision making, how racial/ethnic categories were developed, potential problems of using racial/ethnic categories, and the difference between risk factors and risk markers. The authors make the argument that using a patient's race/ethnicity in clinical decision making often results in a missed or incorrect diagnosis.

Racial/ethnic representation in lifestyle weight loss intervention studies in the United States: A systematic review

Obesity remains a persistent public health and health disparity concern in the United States. Eliminating health disparities, particularly among racial/ethnic minority groups, is a major health priority in the US. The primary aim of this review was to evaluate representation of racial/ethnic sub-group members in behavioral weight loss interventions conducted among adults in the United States. The secondary aims were to assess recruitment and study design approaches to include racial/ethnic groups and the extent of racial/ethnic sub-group analyses conducted in these studies. PubMed, PsycInfo, Medline, and CINAHL were searched for behavioral weight loss intervention trials conducted in 2009–2015 using keywords: weight, loss, overweight, obese, intervention and trial. Most of the 94 studies included a majority of White participants compared to any other racial/ethnic group. Across the included studies, 58.9% of participants were White, 18.2% were African American, 8.7% were Hispanic/Latino, 5.0% were Asian and 1.0% were Native Americans. An additional 8.2% were categorized as “Other”. Nine of the 94 studies exclusively included minority samples. Lack of adequate representation of racial and ethnic minority populations in behavioral trials limits the generalizability and potential public health impact of these interventions to groups that might most benefit from weight loss. Given racial/ethnic disparities in obesity rates and the burden of obesity and obesity-related diseases among minority groups in the United States, greater inclusion in weight loss intervention studies is warranted.

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Describes racial/ethnic minority inclusion in behavioral weight loss studies

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Majority of studies continue to include a majority white sample.

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Modest increases in the representation of some racial/ethnic minority groups.

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Lack of adequate representation of minority groups limits generalizability.

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Greater racial/ethnic inclusion in weight loss intervention studies is warranted.

A Qualitative Analysis of How Anthropologists Interpret the Race Construct

This article assesses anthropological thinking about the race concept and its applications. Drawn from a broader national survey of geneticists' and anthropologists' views on race, in this analysis, we provide a qualitative account of anthropologists' perspectives. We delve deeper than simply asserting that "race is a social construct." Instead, we explore the differential ways in which anthropologists describe and interpret how race is constructed. Utilizing the heuristic of constructors, shifters, and reconcilers, we also illustrate the ways in which anthropologists conceptualize their interpretations of race along a broad spectrum as well as what these differential approaches reveal about the ideological and biological consequences of socially defined races, such as racism in general and racialized health disparities in particular. [race concept, social construction, racism, health disparities].

Primary Care Physicians' Collection, Comfort, and Use of Race and Ethnicity in Clinical Practice in the United States

Purpose: The clinical utility of race and ethnicity has been debated. It is important to understand if and how race and ethnicity are communicated and collected in clinical settings. We investigated physicians' self-reported methods of collecting a patient's race and ethnicity in the clinical encounter, their comfort with collecting race and ethnicity, and associations with use of race in clinical decision-making.

Methods: A national cross-sectional study of 787 clinically active general internists in the United States. Physicians' self-reported comfort with collecting patient race and ethnicity, their collection practices, and use of race in clinical care were assessed. Bivariate and multivariable regression analyses were conducted to examine associations between comfort, collection practices, and use of race.

Results: Most physicians asked patients to self-report their race or ethnicity (26.5%) on an intake form or collected this information directly from patients (26.2%). Most physicians were comfortable collecting patient race and ethnicity (84.3%). Physicians who were more comfortable collecting patient race and ethnicity (β=1.65; [95% confidence interval; CI 0.03–3.28]) or who directly collected patients' race and ethnicity (β=1.24 [95% CI 0.07–2.41]) were more likely to use race in clinical decision-making than physicians who were uncomfortable.

Conclusions: This study documents variation in physician comfort level and practice patterns regarding patient race and ethnicity data collection. As the U.S. population becomes more diverse, future work should examine how physicians speak about race and ethnicity with patients and their use of race and ethnicity data impact patient–physician relationships, clinical decision-making, and patient outcomes.

Measurement invariance of the Eating Disorder Examination in black and white children and adolescents

OBJECTIVE

The Eating Disorder Examination (EDE) was originally developed and validated in primarily white female samples. Since data indicate that eating pathology impacts black youth, elucidating the psychometric appropriateness of the EDE for black youth is crucial.

METHODS

A convenience sample was assembled from seven pediatric obesity studies. The EDE was administered to all youth. Confirmatory factor analyses (CFA) were conducted to examine the original four-factor model fit and two alternative factor structures for black and white youth. With acceptable fit, multiple-group CFAs were conducted. For measurement invariant structures, the interactive effects of race with sex, BMIz, adiposity, and age were explored (all significance levels p < .05).

RESULTS

For both black and white youth (N = 820; 41% black; 37% male; 6-18 years; BMIz -3.11 to 3.40), the original four-factor EDE structure and alternative eight-item one-factor structure had mixed fit via CFA. However, a seven-item, three-factor structure reflecting Dietary Restraint, Shape/Weight Overvaluation, and Body Dissatisfaction had good fit and held at the level of strict invariance. Girls reported higher factor scores than boys. BMIz and adiposity were positively associated with each subscale. Age was associated with Dietary Restraint and Body Dissatisfaction. The interactional effects between sex, BMIz, and age with race were not significant; however, the interaction between adiposity and race was significant. At higher adiposity, white youth reported greater pathology than black youth.

CONCLUSION

An abbreviated seven-item, three-factor version of the EDE captures eating pathology equivalently across black and white youth. Full psychometric testing of the modified EDE factor structure in black youth is warranted.

Challenges and Considerations Related to Studying Dementia in Blacks/African Americans

Blacks/African Americans have been reported to be ∼2-4 times more likely to develop clinical Alzheimer's disease (AD) compared to Whites. Unfortunately, study design challenges (e.g., recruitment bias), racism, mistrust of healthcare providers and biomedical researchers, confounders related to socioeconomic status, and other sources of bias are often ignored when interpreting differences in human subjects categorized by race. Failure to account for these factors can lead to misinterpretation of results, reification of race as biology, discrimination, and missed or delayed diagnoses. Here we provide a selected historical background, discuss challenges, present opportunities, and suggest considerations for studying health outcomes among racial/ethnic groups. We encourage neuroscientists to consider shifting away from using biologic determination to interpret data, and work instead toward a paradigm of incorporating both biological and socio-environmental factors known to affect health outcomes with the goal of understanding and improving dementia treatments for Blacks/African Americans and other underserved populations.

Radical contextualization: contributions to an anthropology of racial/ethnic health disparities

There is indisputable evidence of deep and persistent racial/ethnic inequalities in health status and health care in the USA. Growing awareness of these disparities has fueled a cross-disciplinary debate about appropriate approaches to racial/ethnic disparities in public health research and policy discourse, yet anthropologists have been marginalized in this discourse. What does the current work of anthropologists have to offer that is most useful in the crucial work of understanding and eliminating health disparities? We examine anthropological research and practice that constitute core contributions to an anthropology of racial/ethnic health disparities. We identify the following themes: (1) using ethnography as a tool for new inequality knowledge; (2) studying up; and (3) formulating alternative models of biosocial pathogenesis. These elements of anthropological methods, theory and practice can contribute to a better understanding of the social processes that underpin racial/ethnic health disparities and help identify opportunities for interrupting them.

Genomic research, publics and experts in Latin America: Nation, race and body

The articles in this issue highlight contributions that studies of Latin America can make to wider debates about the effects of genomic science on public ideas about race and nation. We argue that current ideas about the power of genomics to transfigure and transform existing ways of thinking about human diversity are often overstated. If a range of social contexts are examined, the effects are uneven. Our data show that genomic knowledge can unsettle and reinforce ideas of nation and race; it can be both banal and highly politicized. In this introduction, we outline concepts of genetic knowledge in society; theories of genetics, nation and race; approaches to public understandings of science; and the Latin American contexts of transnational ideas of nation and race.

Genetic association meta-analysis: a new classification to assess ethnicity using the association of MCP-1 -2518 polymorphism and tuberculosis susceptibility as a model

Background

In meta-analyses of genetic association studies, ancestry and ethnicity are not accurately investigated. Ethnicity is usually classified using conventional race/ethnic categories or continental groupings even though they could introduce bias increasing heterogeneity between and within studies; thus decreasing the external validity of the results. In this study, we performed a meta-analysis using a novel ethnic classification system to test the association between MCP-1 -2518 polymorphism and pulmonary tuberculosis. Our new classification considers genetic distance, migration and linguistic origins, which will increase homogeneity within ethnic groups.

Methods

We included thirteen studies from three continents (Asia, Africa and Latin America) and considered seven ethnic groups (West Africa, South Africa, Saharan Africa, East Asia, South Asia, Persia and Latin America).

Results

The results were compared to the continental group classification. We found a significant association between MCP-1 -2518 polymorphism and TB susceptibility only in the East Asian and Latin American groups (OR 3.47, P = 0.08; OR 2.73, P = 0.02). This association is not observed in other ethnic groups that are usually considered in the Asian group, such as India and Persia, or in the African group.

Conclusions

There is an association between MCP-1 -2518 polymorphism and TB susceptibility only in the East Asian and Latin American groups. We suggest the use of our new ethnic classification in future meta-analysis of genetic association studies when ancestry markers are not available. This new classification increases homogeneity for certain ethnic groups compared to the continental classification. We recommend considering previous data about migration, linguistics and genetic distance when classifying ethnicity in further studies.

Distribution of the most Common Genetic Variants Associated with a Variable Drug Response in the Population of the Republic of Macedonia

Genetic variation in the regulation, expression and activity of genes coding for Phase I, Phase II drug metabolizing enzymes (DMEs) and drug targets, can be defining factors for the variability in both the effectiveness and occurrence of drug therapy side effects. Information regarding the geographic structure and multi-ethnic distribution of clinically relevant genetic variations is becoming increasingly useful for improving drug therapy and explaining inter-individual and inter-ethnic differences in drug response.

This study summarizes our current knowledge about the frequency distribution of the most common allelic variants in three broad gene categories: the Phase I oxidation-cytochrome P450 (CYP450) family (CYP2C9, CYP2C19, CYP3A5, CYP2D6); the Phase II conjugation (GSTT1, SULT1A1; UGT1A1) and drug target (TYMS-TSER, MTHFR and VKORC1) in the population of the Republic of Macedonia and compares the information obtained with data published for other indigenous European populations.

Our findings define the population of the Republic of Macedonia as an ethnic group with a highly polymorphic genetic profile. These results add to the evidence regarding the distribution of clinically important variant alleles in DME and drug target genes in populations of European ancestry.

Correlation between microsatellite discrepancy scores and transplant outcome after haemopoietic SCT for pediatric ALL

Microsatellite analyses show that self-reported ethnicity often correlates poorly with true genetic ancestry. As unknown ancestral differences could potentially have an impact on transplant outcome, we developed an average allele length discrepancy (AALD) score to assess allele length discrepancy between donor/recipient (D/R) using microsatellites analysed routinely in post-transplant chimeric assessment. This was then compared with outcome in a homogeneously treated cohort of pediatric patients undergoing high-resolution sibling or matched unrelated donor transplantation for acute lymphoblastic leukemia (ALL). AALD scores formed a numeric continuum ranging from 0 to 1.4 (median 0.76) for sibling pairs and 0.8-2.17 (median 1.6) for high-resolution matched unrelated donor (HR-MUD) pairs. There was a trend for worse OS with increasing AALD score, which reached statistical significance above a threshold of 1.7 for OS. Patients whose transplants had an AALD score of ⩾1.8 had a risk of non-relapse mortality 4.9 times greater (P=0.025) and relapse risk three times greater (P=0.058) than those scoring <1.8. This approach will now be explored in a Centre International for Blood and Marrow Transplantation Research (CIBMTR) study of 750 D/R pairs across all disease groups; if confirmed, it has the potential to improve donor selection for patients with multiple prospective donors.

Self-reported race/ethnicity in the age of genomic research: its potential impact on understanding health disparities

This review explores the limitations of self-reported race, ethnicity, and genetic ancestry in biomedical research. Various terminologies are used to classify human differences in genomic research including race, ethnicity, and ancestry. Although race and ethnicity are related, race refers to a person's physical appearance, such as skin color and eye color. Ethnicity, on the other hand, refers to communality in cultural heritage, language, social practice, traditions, and geopolitical factors. Genetic ancestry inferred using ancestry informative markers (AIMs) is based on genetic/genomic data. Phenotype-based race/ethnicity information and data computed using AIMs often disagree. For example, self-reporting African Americans can have drastically different levels of African or European ancestry. Genetic analysis of individual ancestry shows that some self-identified African Americans have up to 99% of European ancestry, whereas some self-identified European Americans have substantial admixture from African ancestry. Similarly, African ancestry in the Latino population varies between 3% in Mexican Americans to 16% in Puerto Ricans. The implication of this is that, in African American or Latino populations, self-reported ancestry may not be as accurate as direct assessment of individual genomic information in predicting treatment outcomes. To better understand human genetic variation in the context of health disparities, we suggest using "ancestry" (or biogeographical ancestry) to describe actual genetic variation, "race" to describe health disparity in societies characterized by racial categories, and "ethnicity" to describe traditions, lifestyle, diet, and values. We also suggest using ancestry informative markers for precise characterization of individuals' biological ancestry. Understanding the sources of human genetic variation and the causes of health disparities could lead to interventions that would improve the health of all individuals.

Blood politics, ethnic identity, and racial misclassification among American Indians and Alaska Natives

Misclassification of race in medical and mortality records has long been documented as an issue in American Indian/Alaska Native data. Yet, little has been shared in a cohesive narrative which outlines why misclassification of American Indian/Alaska Native identity occurs. The purpose of this paper is to provide a summary of the current state of the science in racial misclassification among American Indians and Alaska Natives. We also provide a historical context on the importance of this problem and describe the ongoing political processes that both affect racial misclassification and contribute to the context of American Indian and Alaska Native identity.

Disaggregating race and ethnicity in chronic health conditions: implications for public health social work

This study examines the ethnic subgroup variation in chronic health by comparing self-reports of chronic conditions across diverse ethnic subgroups of Asian American (Vietnamese, Filipino, Chinese), Latino American (Cuban, Portuguese, Mexican), and African Caribbean (Haitian, Jamaican, Trinidadian/Tobagonian) respondents. This analysis utilizes linked data from the Collaborative Psychiatric Epidemiology Surveys (CPES). Logistic regression revealed significant subgroup differences in reports of chronic respiratory, cardiovascular, and pain conditions across nine ethnic subgroups masked by racial categorization. Findings suggest that precautions must be taken by public health social workers as there may be far more ethnic heterogeneity than is apparent among broad racial categories.

Population genetic structure of Anopheles arabiensis and Anopheles gambiae in a malaria endemic region of southern Tanzania

BACKGROUND

Genetic diversity is a key factor that enables adaptation and persistence of natural populations towards environmental conditions. It is influenced by the interaction of a natural population's dynamics and the environment it inhabits. Anopheles gambiae s.s. and Anopheles arabiensis are the two major and widespread malaria vectors in sub-Saharan Africa. Several studies have examined the ecology and population dynamics of these vectors. Ecological conditions along the Kilombero valley in Tanzania influence the distribution and population density of these two vector species. It remains unclear whether the ecological diversity within the Kilombero valley has affected the population structure of An. gambiae s.l. populations. The goal of this study was to characterise the genetic structure of sympatric An. gambiae s.s and An. arabiensis populations along the Kilombero valley.

METHODOLOGY

Mosquitoes were collected from seven locations in Tanzania: six from the Kilombero valley and one outside the valley (-700 km away) as an out-group. To archive a genome-wide coverage, 13 microsatellite markers from chromosomes X, 2 and 3 were used.

RESULTS

High levels of genetic differentiation among An. arabiensis populations was observed, as opposed to An. gambiae s.s., which was genetically undifferentiated across the 6,650 km2 of the Kilombero valley landscape. It appears that genetic differentiation is not attributed to physical barriers or distance, but possibly by ecological diversification within the Kilombero valley. Genetic divergence among An. arabiensis populations (FST = 0.066) was higher than that of the well-known M and S forms of An. gambiae s. s. in West and Central Africa (FST = 0.035), suggesting that these populations are maintained by some level of reproductive isolation.

CONCLUSION

It was hypothesized that ecological diversification across the valley may be a driving force for observed An. arabiensis genetic divergence. The impact of the observed An. arabiensis substructure to the prospects for new vector control approaches is discussed.

Informed consent in the context of pharmacogenomic research: ethical considerations

Although the scientific research surrounding pharmacogenomics (PGx) has been relatively plentiful, the ethical research concerning this discipline has developed rather conservatively. Following investigation of the ethical, legal and social issues (ELSI) of PGx research, as well as consulting with key stakeholders, we identified six outstanding ethical issues raised by the informed consent process in PGx research: (1) scope of consent; (2) consent to 'add-on' studies; (3) protection of personal information; (4) commercialization; (5) data sharing; and (6) potential risks stemming from population-based research. In discussing these six areas as well as offering specific considerations, this article offers a solid base from which future practical guidelines for informed consent in PGx research can be constructed. As such, this effort works toward filling the ELSI gap and provides ethical support to the numerous PGx projects undertaken by researchers every year.

Caspase 8 gene variants in healthy North Indian population and comparison with worldwide ethnic group variations

BACKGROUND:

Many strategies are being used for the quest for the disease causing genes. Inter-individual variations in several genes exist. Thus, even if they share the same disease-associated allele, the genomic backgrounds – and hence potential interacting alleles at other loci – of people with different regional ancestries may differ, with a consequent variation in the severity of their disease.

MATERIALS AND METHOD:

The present study was conducted to determine the distribution of Caspase 8 IVS12-19G/A, Caspase 8D302H, Caspase 8 -652del and Caspase 8 -678del polymorphisms (as frequency distribution of caspases in Indians generally is not yet known), which was then compared with different populations globally. Polymerase chain reaction (PCR)-based analysis was conducted in 205 normal healthy individuals of similar ethnicity.

RESULTS:

The variant allele frequencies were 17.6% (A) in Caspase 8 IVS12-19G/A, 13.2% (H) in Caspase 8D302H, 23.2% (Del) in Caspase 8 -652del and 24.6% (Del) in Caspase 8 -678del. Further, comparison of frequency distribution of these genes was done with various published studies of different ethnic groups globally.

CONCLUSION:

It is anticipated from our results that the frequency of these caspase genes exhibits distinctive patterns in India, which could perhaps be attributed to ethnic variation. This study is important as it can form a baseline for screening individuals who are at high risk due to exposure to environmental carcinogens and cancer predisposition, and therefore, might help in investigating linked polymorphisms in a way that will not obscure potential associations between genotype and phenotype.

Human genome diversity: frequently asked questions

Despite our relatively large population size, humans are genetically less variable than other primates. Many allele frequencies and statistical descriptors of genome diversity form broad gradients, tracing the main expansion from Africa, local migrations, and sometimes adaptation. However, this continuous variation is discordant across loci, and principally seems to reflect different blends of common and often cosmopolitan alleles rather than the presence of distinct gene pools in different regions of the world. The elusive structure of human populations could lead to spurious associations if the effects of shared ancestry are not properly dealt with; indeed, this is among the causes (although not the only one) of the difficulties encountered in discovering the loci responsible for quantitative traits and complex diseases. However, the rapidly growing body of data on our genomic diversity has already cast new light on human population history and is now revealing intricate biological relationships among individuals and populations of our species.