PopCluster: an algorithm to identify genetic variants with ethnicity-dependent effects

Race and ethnicity dynamics in survival to 100 years in the United States

BACKGROUND

After age 85, the U.S. non-Hispanic Black population mortality rate becomes less than that of the White population (called the Black-White mortality crossover). It is not known how this survival advantage compares to Asian and Hispanic groups, and whether differences persist to age 100+ years.

METHODS

The U.S. period life table data were extracted to obtain life expectancy at birth and at ages 70, 85, and 100 years according to year, sex, and race and ethnicity. Age-specific death rates and adult modal age at death were calculated. We computed period probabilities of survival to age 100, from ages 70, 80, and 90. Pseudo-birth cohort calculations were undertaken to enable comparison with period-based results.

RESULTS

In 2019, the Black-White mortality crossover occurred at 86-88 years and persisted at ages 100 and 100+. Life expectancies at age 100 for non-Hispanic Black, Hispanic, and Asian populations were similar and were significantly greater than the non-Hispanic White population. From 2006 to 2019, the probability of survival from 70 and 80 years to age 100 was highest for the Hispanic population, followed by non-Hispanic Black and then non-Hispanic White populations. Probability of survival from age 90 to 100 years was similar for all but the non-Hispanic White population, which had a comparatively lower probability of survival. When Asian population data became available in 2019, this population had the highest probability of survival to age 100, starting from ages 70, 80, and 90 years. Pseudo-cohort results displayed patterns consistent with those observed over calendar years.

CONCLUSIONS

Race- and ethnicity-based variation in mortality between ages 85 and 100+ years suggests differences in environmental and possibly genetic influences upon risk for exceptional longevity.

Development of a 50K SNP array for whole-genome analysis and its application in the genetic localization of eggplant (Solanum melongena L.) fruit shape

Introduction

Current eggplant variety breeding is still mainly based on conventional methods, and there remains a lack of effective molecular breeding systems for complex traits controlled by multiple genes, such as yield and quality. To accelerate the research progress of eggplant genetics and molecular breeding, it is necessary to implement a genome-based breeding strategy.

Methods

Therefore, in this study, a SNP array containing 50K liquid-phase probes was designed on the basis of the resequencing data of 577 eggplants.

Results

The developed 50K liquid-phase probes were used to perform targeted capture sequencing on 12 eggplant lines, and the efficiency of probe capture exceeded 99.25%. Principal component, phylogenetic, and population structure analyses divided the 577 eggplants into 7 subgroups, and statistical analysis was performed on the fruit shape and color of the materials in the different subgroups. Further analysis of the geographical distribution of 428 Chinese eggplant materials revealed that the geographical regions of different subgroups were similar. The 50K SNP liquid-phase array was used to perform bulked- segregant analysis combined with whole-genome resequencing (BSA-seq) of fruit shape in the F2 population, which consisted of 1435 lines constructed with E421 as the maternal parent and 145 as the paternal parent. The BSA-seq data were located in the 78444173-84449348 interval on chromosome 3, with a size of 6 Mb, which was narrowed to 712.6 kb through fine mapping. Further sequence alignment and expression analysis revealed SmIQD14 as a candidate gene controlling eggplant fruit shape. The 50K SNP liquid-phase array can be widely used in future eggplant molecular breeding research.

Population structure analysis of Phlebotomus papatasi populations using transcriptome microsatellites: possible implications for leishmaniasis control and vaccine development

BACKGROUND

Phlebotomus papatasi is considered the primary vector of Leishmania major parasites that cause zoonotic cutaneous leishmaniasis (ZCL) in the Middle East and North Africa. Phlebotomus papatasi populations have been studied extensively, revealing the existence of different genetic populations and subpopulations over its large distribution range. Genetic diversity and population structure analysis using transcriptome microsatellite markers is important to uncover the vector distribution dynamics, essential for controlling ZCL in endemic areas.

METHODS

In this study, we investigated the level of genetic variation using expressed sequence tag-derived simple sequence repeats (EST-SSRs) among field and colony P. papatasi samples collected from 25 different locations in 11 countries. A total of 302 P. papatasi sand fly individuals were analyzed, including at least 10 flies from each region.

RESULTS

The analysis revealed a high-level population structure expressed by five distinct populations A through E, with moderate genetic differentiation among all populations. These genetic differences in expressed genes may enable P. papatasi to adapt to different environmental conditions along its distribution range and likely affect dispersal.

CONCLUSIONS

Elucidating the population structuring of P. papatasi is essential to L. major containment efforts in endemic countries. Moreover, the level of genetic variation among these populations may improve our understanding of Leishmania-sand fly interactions and contribute to the efforts of vaccine development based on P. papatasi salivary proteins.

Leveraging human-mouse studies to advance the genetics of hearing impairment in Africa

Mouse models are used extensively to understand human pathobiology and mechanistic functions of disease-associated loci. However, in this review, we investigate the potential of using genetic mouse models to identify genetic markers that can disrupt hearing thresholds in mice and then target the hearing-enriched orthologues and loci in humans. Currently, little is known about the real prevalence of genes that cause hearing impairment (HI) in Africa. Pre-screening mouse cell lines to identify orthologues of interest has the potential to improve the genetic diagnosis for HI in Africa to a significant percentage, for example, 10-20%. Furthermore, the functionality of a candidate gene derived from mouse screening with heterogeneous genetic backgrounds and multi-omic approaches can shed light on the molecular, genetic heterogeneity and plausible mode of inheritance of a gene in hearing-impaired individuals especially in the absence of large families to investigate.

A Genome-Wide Association Study of 2304 Extreme Longevity Cases Identifies Novel Longevity Variants

We performed a genome-wide association study (GWAS) of human extreme longevity (EL), defined as surviving past the 99th survival percentile, by aggregating data from four centenarian studies. The combined data included 2304 EL cases and 5879 controls. The analysis identified a locus in CDKN2B-AS1 (rs6475609, p = 7.13 × 10-8) that almost reached genome-wide significance and four additional loci that were suggestively significant. Among these, a novel rare variant (rs145265196) on chromosome 11 had much higher longevity allele frequencies in cases of Ashkenazi Jewish and Southern Italian ancestry compared to cases of other European ancestries. We also correlated EL-associated SNPs with serum proteins to link our findings to potential biological mechanisms that may be related to EL and are under genetic regulation. The findings from the proteomic analyses suggested that longevity-promoting alleles of significant genetic variants either provided EL cases with more youthful molecular profiles compared to controls or provided some form of protection from other illnesses, such as Alzheimer's disease, and disease progressions.

Varying Effects of APOE Alleles on Extreme Longevity in European Ethnicities

APOE is a well-studied gene with multiple effects on aging and longevity. The gene has three alleles: e2, e3, and e4, whose frequencies vary by ethnicity. While the e2 is associated with healthy cognitive aging, the e4 allele is associated with Alzheimer's disease and early mortality and therefore its prevalence among people with extreme longevity (EL) is low. Using the PopCluster algorithm, we identified several ethnically different clusters in which the effect of the e2 and e4 alleles on EL changed substantially. For example, PopCluster discovered a large group of 1,309 subjects enriched of Southern Italian genetic ancestry with weaker protective effect of e2 (odds ratio [OR] = 1.27, p = .14) and weaker damaging effect of e4 (OR = 0.82, p = .31) on the phenotype of EL compared to other European ethnicities. Further analysis of this cluster suggests that the odds for EL in carriers of the e4 allele with Southern Italian genetic ancestry differ depending on whether they live in the United States (OR = 0.29, p = .009) or Italy (OR = 1.21, p = .38). PopCluster also found clusters enriched of subjects with Danish ancestry with varying effect of e2 on EL. The country of residence (Denmark or United States) appears to change the odds for EL in the e2 carriers.

Bioarchaeological perspective on the expansion of Transeurasian languages in Neolithic Amur River basin

Owing to the development of sequencing technology, paleogenomics has become an important source of information on human migration and admixture, complementing findings from archaeology and linguistics. In this study, we retrieved the whole genome and Y chromosome lineage from late Neolithic Honghe individuals in the Middle Amur region in order to provide a bioarchaeological perspective on the origin and expansion of Transeurasian languages in the Amur River basin. Our genetic analysis reveals that the population of the Amur River basin has a stable and continuous genetic structure from the Mesolithic Age up to date. Integrating linguistic and archaeological evidence, we support the hypothesis that the expansion of the Transeurasian language system in the Amur River basin is related to the agricultural development and expansion of the southern Hongshan culture. The spread of agricultural technology resulted in the addition of millet cultivation to the original subsistence mode of fishing and hunting. It played a vital role in the expansion of the population of the region, which in its turn has contributed to the spread of language.