The genetic relationship among Iranian ethnic groups: an anthropological view based on HLA class II gene polymorphism

Narrating ethnicity and diversity in Middle Eastern national genome projects

Most Middle Eastern populations outside Israel have not been represented in Western-based international human genome sequencing efforts. In response, national-level projects have emerged throughout the Middle East to decode the Arab, Turkish and Iranian genomes. The discourses surrounding the 'national genome' that shape scientists' representation of their work to local and international audiences evoke three intersecting analytics of nationalism: methodological, postcolonial and diasporic. Methodologically, ongoing human genome projects in Turkey and Iran follow the population logics of other national and international genome projects, for example justifying research with reference to projected health benefits to their fellow citizens. Meanwhile, assumptions about and representations of ethnicity and diversity are deeply inflected by local histories of scientific development and nationalist politics. While Iranian geneticists have transformed this paradigm to catalog national genetic diversity through a discourse of 'Iranian ethnicities', Turkish geneticists remain politically constrained from acknowledging ethnic diversity and struggle to distance their work from racialized narratives of Turkish national identity. Such nationally-framed narratives of genomic diversity are not confined to their original contexts, but travel abroad, as demonstrated by a US-based genome project that articulates a form of Iranian-American diasporic nationalism.

High-Resolution HLA-A Typing in Normal Iranian Population

Background:

Human leukocyte antigen (HLA) gene is a highly polymorphic region. HLA typing is required to match patients and donors for transplantation; therefore, development of HLA registries is necessary for finding HLA match donors. HLA system is highly informative, and numerous studies have been conducted on HLA allele distribution in different populations.

Methods:

In this study, 100 unrelated Iranian individuals were typed for HLA-A locus using sequence-based typing method. Samples were subjected to the PCR, followed by Sanger sequencing and software analysis.

Results:

A*02:01 (13%) and A*24:02 (12%) were the two most frequent alleles, while A*01:14, A*02:05, A*02:11, A*02:34, A*02:50, A*11:04, A*23:02, A*24:34, A*25:01, A*26:09, A*26:43, A*29:67, A*30:54, A*31:02, A*31:66, A*32:03, A*32:04, A*33:03, and A*66:15 alleles had the least frequencies (1%).

Conclusion:

This is the first report of HLA-A allele level typing in a randomized population of Iran and can be useful for development of national registries of HLA-typed volunteer marrow donors and local cord blood banks.

Impact of CYP2C19 Polymorphisms on Serum Concentration of Voriconazole in Iranian Hematological Patients

OBJECTIVE

This study aimed to determine the portion of Iranian patients who attain therapeutic serum concentrations of voriconazole (VRCZ) following administration of fixed doses. In addition, the effect of CYP2C19 polymorphism on serum levels of VRCZ was also investigated.

METHODS

Forty-eight adult patients of Iranian origin with hematologic malignancies, who received VRCZ for treatment of invasive aspergillosis, were recruited into the study. Blood samples were drawn at day 4 of treatment to measure trough drug concentrations and determine genotyping of CYP2C19 polymorphisms of each patient. High-performance liquid chromatography method was used for measuring VRCZ serum level and CYP2C19 polymorphisms were conducted by Sanger sequencing. Demographic and clinical characteristics of patients alongside with CYP2C19 polymorphisms were assessed to determine the effective factor/s on VRCZ serum concentration.

FINDINGS

Seventy-three percent of patients achieved therapeutic serum concentrations of VRCZ with administration of usual fixed doses in clinical practice. There was no correlation between weight-adjusted dose and serum concentrations of VRCZ. Mean serum levels were significantly different neither in genders nor in routes of administrations. Extensive and ultrarapid metabolizers (URMs) comprised 48.7% and 21.6% study population, respectively. CYP2C19 polymorphism dramatically influenced the trough levels of VRCZ, so that all patients with subtherapeutic levels expressed URM phenotype.

CONCLUSION

With respect to high incidence of URM phenotype in Iranian population, and observed association of this phenotype with sub-therapeutic levels in our study, performing therapeutic drug monitoring is strongly recommended for all patients.

A genomic study on distribution of human leukocyte antigen (HLA)-A and HLA-B alleles in Lak population of Iran

Anthropological studies based on the highly polymorphic gene, human leukocyte antigen (HLA), provide useful information for bone marrow donor registry, forensic medicine, disease association studies, as well as infertility treatment, designing peptide vaccines against tumors, and infectious or autoimmune diseases. The aim of this study was to determine HLA-A and HLA-B allele frequencies in 100 unrelated Lak/lᴂk/individuals from Lorestan province of Iran. Finally, we compared the results with that previously described in Iranian population. Commercial HLA-Type kits from BAG (Lich, Germany) company were used for determination of the HLA-A and HLA-B allele frequencies in genomic DNA, based on polymerase chain reaction with sequence specific primer (PCR-SSP) assay. The differences between the populations in distribution of HLA-A and HLA-B alleles were estimated by chi-squared test with Yate's correction. The most frequent HLA-A alleles were *24 (20%), *02 (18%), *03 (12%) and *11 (10%), and the most frequent HLA-B alleles were *35 (24%), *51 (16%), *18 (6%) and *38 (6%) in Lak population. HLA-A*66 (1%), *74(1%) and HLA-B*48 (1%), *55(1%) were the least observed frequencies in Lak population. Our results based on HLA-A and HLA-B allele frequencies showed that Lak population possesses the previously reported general features of Iranians but still with unique.

HLA class I variation in Iranian Lur and Kurd populations: high haplotype and allotype diversity with an abundance of KIR ligands

HLA-A, -B and -C alleles of 285 individuals, representing three Iranian Lur populations and one Iranian Kurd population were sequenced completely, yielding human leukocyte antigen (HLA) class I genotypes at high resolution and filling four fields of the official HLA nomenclature. Each population has 87-99 alleles, evenly distributed between the three HLA class I genes, 145 alleles being identified in total. These alleles were already known, named and deposited in the HLA database. The alleles form 316 different HLA A-B-C haplotypes, with each population having between 80 and 112 haplotypes. The four Iranian populations form a related group that is distinguished from other populations, including other Iranians. All four KIR ligands - the A3/11, Bw4, C1 and C2 epitopes - are well represented, particularly Bw4, which is carried by three high-frequency allotypes: HLA-A*24:02, HLA-A*32:01 and HLA-B*51:01. In the Lur and Kurd populations, between 82% and 94% of individuals have the Bw4 epitope, the ligand for KIR3DL1. HLA-B*51:01 is likely of Neandertal origin and associated with Behcet's disease, also known as the Silk Road disease. The Lordegan Lur have the highest frequency of HLA-B*51:01 in the world. This allele is present on 46 Lur and Kurd haplotypes. Present at lower frequency is HLA-B*51:08, which is also associated with Behcet's disease. In the four Iranian populations, 31 haplotypes encode both Bw4(+) HLA-A and Bw4(+) HLA-B, a dual combination of Bw4 epitopes that is relatively rare in other populations, worldwide. This study both demonstrates and emphasizes the value of studying HLA class I polymorphism at highest resolution in anthropologically well-defined populations.

Distribution of HLA-DRB1 and HLA-DQB1 alleles in Lak population of Iran

Human leukocyte antigen (HLA) genes are the most polymorphic loci in the human genome and encode the highly polymorphic molecules critically involved in immune responses. Anthropological studies based on highly polymorphic HLA genes provide useful information for bone marrow donor registry, forensic medicine, disease association studies, as well as designing peptide vaccines against tumors, and infectious or autoimmune diseases. The aim of this study was to determine the HLA-DRB1 and HLA-DQB1 allele frequencies in 100 unrelated Lak individuals from Lorestan province of Iran. Finally, we compared the results with those previously described in four other Iranian populations. Commercial HLA-Type kits were used for determination of the HLA-DRB1 and HLA-DQB1 allele frequencies. Differences between populations in the distribution of HLA-DRB1 and HLA-DQB1 alleles were estimated by χ2 test with Yate's correction and Fisher's exact test. The most frequent HLA-DRB1 alleles were (*)1103=4 (23%), (*)1502 (9.5%), (*)0701 (9%), (*)0301 (8.5%), (*)1101 (7.5%) and (*)1501 (6%) while HLA-DQB1(*)0301 (40%), (*)0201 (15%), (*)0502 (10.5%), (*)0303 (10%), (*)0602=3 (9.5%), and (*)0501 (7.5%) were the most frequent alleles in Lak population. HLA-DRB1(*)0409, (*)0804, (*)1102, (*)1112, (*)1405, and HLA-DQB1(*)0503, (*)0604 were the least observed frequencies in Lak population. Our results based on HLA-DRB1 and HLA-DQB1 allele frequencies showed that the Lak population possesses the previously reported general features of the Lur and Kurd populations but still with unique, decreased or increased frequencies of several alleles. In other words, the Lak population is close to Lurs Khorramabadi and Kurd but far from Lurs Kohkiloyeh/Boyerahmad and Bakhtiari.

Association involving serotonin transporter gene linked polymorphic region and bipolar disorder type 1 in Iranian population

INTRODUCTION

Serotonin transporter gene linked polymorphic region, also called 5HTTLPR, is a candidate in the genetics of bipolar disorder; however, the results of previous association studies are inconsistent. Several explanations have been proposed for that inconsistency; among them are the existing differences both in the genetic basis of bipolar disorder subtypes and the genetic backgrounds of the studied populations. We aimed to investigate the association of 5HTTLPR with bipolar disorder type I (BP-1) in Iranian population.

METHODS

In this case-control study, 146 patients with BP-1 and 165 controls were recruited. The patients were selected through the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, 4th edition. It was required that the patients do not have any present history of general medical conditions, substance abuse, and concurrent major psychiatric disorders. The polymorphism was evaluated by blood sampling and subsequent DNA extraction, polymerase chain reaction, and agarose gel electrophoresis. Chi-square test was used for analyzing allelic and genotype frequencies and two-tailed P values were obtained.

RESULTS

The S allele was significantly more frequent in the BP-1 patients compared with the controls (P = 0.02, S allele odds ratio = 1.5, confidence interval 95% = 1.06-2.11).

DISCUSSION

Our statistically significant results suggest that the role of 5HTTLPR in the pathogenesis of BP-1 needs to be clarified by further scrutiny in Iranian population and other populations of Near East.

Gorgan (Turkmen in Iran) HLA genetics: transplantation, pharmacogenomics and anthropology

HLA class I and II alleles have been studied in a population from Gorgan (North East Iranian city bordering Turkmenistan). This population is composed of mainly Turkmen who speak Oghuz Turkish language. Comparison of Gorgan people HLA profile has been carried out with about 7984 HLA chromosomes from other worldwide populations; extended haplotypes and three dimension genetic distances have been calculated by using neighbor-joining and correspondence relatedness analyses. Most frequent extended HLA haplotypes show a Siberian/Mediterranean admixture and closest populations are Chuvashians (North Caspian Sea, Russia) and other geographically close populations like Siberian Mansi, Buryats and other Iranians. New extended HLA haplotypes have been found, such as: A*31:01-B*35:01-DRB1*15:01-DQB1*03:01, A*01:01-B*35:01-DRB1*03:01-DQB1*02:01. Relationships of Turkmen with Kurgan (Gorgan) archaeological mounds, Scythians and Sarmatians are discussed. This study is also useful for a future transplantation Gorgan waiting list, Gorgan HLA and disease epidemiology and HLA pharmacogenomics.

The Royan Public Umbilical Cord Blood Bank: Does It Cover All Ethnic Groups in Iran Based on HLA Diversity?

BACKGROUND

Umbilical cord blood (UCB) stem cells allow the transplantation of partially human leukocyte antigen (HLA)-matched grafts and are a valuable resource for the treatment of hematologic malignancies and heritable hematologic, immunologic and metabolic diseases, especially when a compatible bone marrow donor is unavailable. The aim of this study was to determine how many ethnic groups in Iran are covered by the available UCB units based on HLA diversity.

METHODS

From 2009 until mid-2013, 4,981 (30.3%) of the 16,437 UCB samples collected met the storage criteria and were cryopreserved at a public cord blood bank (CBB) in Tehran, Iran. HLA-A, -B and -DRB1 were typed in 1,793 samples.

RESULTS

The mean volume of the cryopreserved samples was 81.25 ± 20.3 ml. The range of total nucleated cells per unit was 51 × 10(7)-107 × 10(7). The most common HLA alleles were HLA-A*2 (17%) and HLA-A*24 (15.6%), HLA-B*35 (16.8%) and HLA-B*51 (13.9%), and HLA-DRB1*11 (20%) and HLA-DRB1*15 (14%). The predominant haplotypes were HLA-A*24-B*35-DRB1*11 (2%), HLA-A*02-B*50-DR*07 (1.8%), and HLA-A*02-B*51-DRB1*11 (1.5%).

CONCLUSIONS

Based on the HLA-DRB1 profiles, the UCB units available at the Royan public UCB bank are a potentially adequate resource for hematopoietic stem cell transplantation for Iranian recipients belonging to particular ethnic groups. Regular educational programs to improve the public knowledge of UCB for transplantation can enhance the public CBB stocks for all Iranian ethnic groups in the future.

Multiple sclerosis in the Iranian immigrant population of BC, Canada: prevalence and risk factors

Background:

There is a well-documented increase in the risk of multiple sclerosis (MS) when migrating from a region of low prevalence to one of high prevalence.

Objective:

We present here an investigation of MS prevalence and candidate environmental and genetic risk factors among Iranian immigrants to British Columbia (BC), Canada.

Methods:

MS cases of Iranian ancestry were ascertained from a population-based Canadian study. We collected blood samples for genetic and serological analyses, and administered a personal history questionnaire to the cases.

Results:

The crude prevalence of MS in this population of Iranian ancestry was 287/100,000 (95% CI: 229 – 356/100,000). MS cases were more likely to have a history of infectious mononucleosis (odds ratio (OR) = 7.5; p = 0.005) and smoking (OR = 17.0; p < 0.0001), as compared to healthy controls from previous studies in Iran. Cases were also more likely than controls to have been born between April and September (OR = 2.1; p = 0.019).

Conclusion:

The prevalence of MS among Iranian immigrants to Canada is greater than the overall prevalence of MS in Iran by a factor of at least four, and is similar to that recently observed among Iranian immigrants in other western nations. No major genetic susceptibility variants were identified, suggesting the environment in Canada may be what is increasing the risk of MS in this population.

Serotonin transporter gene polymorphisms in Southwestern Iranian patients with irritable bowel syndrome

BACKGROUND AND STUDY AIMS

Irritable bowel syndrome is a common chronic functional gastrointestinal disorder of unknown etiology. Serotonin is an important factor in sensory signaling in the brain-gut axis, which plays a key role in intestinal motility and secretion. Serotonin clearance is mediated by a specific protein called the serotonin reuptake transporter. Transcription activity of the serotonin transporter gene is affected by some polymorphisms in this gene. The aim of this study was to investigate the relationship between serotonin transporter gene polymorphisms and irritable bowel syndrome.

PATIENTS/MATERIAL AND METHODS

The 5-HTTLPR, rs25531 and STin2VNTR polymorphisms of the serotonin transporter gene were analyzed by PCR-based methods in 50 patients with irritable bowel syndrome and 100 healthy controls.

RESULTS

Serotonin transporter polymorphisms were similar in patients and healthy controls. There were no significant differences in allele or genotype frequencies between the two groups.

CONCLUSION

Our findings suggest that polymorphisms in the gene encoding for the serotonin transporter are not associated with irritable bowel syndrome. Interactions between environmental factors and predisposing genetic factors are important in the pathophysiology of irritable bowel syndrome, and further genetic and epigenetic research may provide novel insights into the mechanisms contributing to this disease.

The association between a single nucleotide polymorphism rs11966200 in MHC region and clinical features of generalized vitiligo in Chinese Han population

Vitiligo is an acquired pigmentary disorder characterized by loss of epidermal melanocytes. A strong association at a single nucleotide polymorphism (SNP) rs11966200 within MHC region had been identified in a recent genome-wide association study of generalized vitiligo in Chinese Han population. This study aims to investigate the relationships between SNP rs11966200 and the clinical features of generalized vitiligo in Chinese Han population. We compared the allele and genotype frequency among different vitiligo subphenotypes including age onset, extent of disease, clinical subtypes, family history of vitiligo and history of autoimmune disease. Our data showed SNP rs11966200 was associated with early-onset vitiligo (onset age ≤ 20 years) (odds ratio [OR], 1.54; p = 2.01 × 10(-13)), moderate-severe vitiligo (involved body surface ≥ 5 %) (OR, 1.17; p = 0.025), vitiligo vulgaris (OR, 1.13; p = 0.043), and focal vitiligo (OR, 0.86; p = 0.018). The study suggested that the underlying risk causal allele tagged by SNP rs11966200 might not only play important roles in the development of vitiligo, but also contribute to the diverse clinical characteristics of generalized vitiligo at least in Chinese Han population.

Human leukocyte antigen variation among Iranian renal transplant recipients

BACKGROUND

HLA typing analysis is important in renal transplant patients.

OBJECTIVES

We made a plan to determine the most frequent HLA antigens in Iranian kidney transplant patients.

PATIENTS AND METHODS

In a retrospective cross sectional study, HLA patterns were defined in 512 kidney transplant recipients (67% male and 33% female) from different transplant centers of Tehran, Iran between 2008 and 2011 by microcytotoxicity assay.

RESULTS

The studies samples were of different ethnic groups of the Iranian kidney transplants. Considerable variations were observed in each HLA sub class. A2, A1, A3, A24 and A26 were the most frequent HLA-A antigens. Among HLA-B, the predominant antigens were B35; B13, B15, B13 and B18. The most frequent HLA-DR antigens were DR 4, DR11, DR1, DR3 and DR15. DQ1 showed the highest frequency and followed by DQ3 and DQ2.

CONCLUSIONS

These results showed considerable heterogeneity in both HLA class I and class II antigens, which reflects recent admixture of this group with neighboring Middle East populations.

High variability of TLR4 gene in different ethnic groups in Iran

Infectious diseases exert a constant evolutionary pressure on the innate immunity genes. TLR4, an important member of the TLR family, specifically recognizes conserved structures of various infectious pathogens. Two functional TLR4 polymorphisms, Asp299Gly and Thr399Ile, modulate innate host defense against infections, and their prevalence between various populations has been proposed to be influenced by local infectious pressures. If this assumption is true, strong local infectious pressures would lead to a homogeneous pattern of these ancient TLR4 polymorphisms in geographically-close populations, while a weak selection or genetic drift may result in a diverse pattern. We evaluated TLR4 polymorphisms in 15 ethnic groups in Iran, to assess whether infections exerted selective pressures on different haplotypes containing these variants. The Iranian subpopulations displayed a heterogeneous pattern of TLR4 polymorphisms, comprising various percentages of Asp299Gly and Thr399Ile, alone or in combination. The Iranian sample, as a whole, showed an intermediate mixed pattern when compared with commonly-found patterns in Africa, Europe, Eastern Asia and the Americas. These findings suggest a weak, or absent, selection pressure on TLR4 polymorphisms in the Middle-East that does not support the assumption of an important role of these polymorphisms in the host defense against local pathogens.

The frequency and distribution of thiopurine S-methyltransferase alleles in south Iranian population

Thiopurine methyltransferase (TPMT) catalyzes the S-methylation of thiopurine drugs such as 6-mercaptopurine, 6-thioguanine, and azathiopurine. Variability in TPMT activity is mainly due to genetic polymorphism. The frequency of the four allelic variants of the TPMT gene, TPMT*2 (G238C), TPMT*3A (G460A and A719G), TPMT*3B (G460A) and TPMT*3C (A719G) were determined in an Iranian population from south of Iran (n = 500), using polymerase chain reaction (PCR)-RFLP and allele-specific PCR-based assays. Four hundred seventy four persons (94.8%) were homozygous for the wild type allele (TPMT*1/*1) and twenty five people were TPMT*1/*3C (5%). One patient was found to be heterozygous in terms TPMT*1 and *2 alleles with genotype of TPMT*1/*2 (0.2%). None of the participants had both defective alleles. The TPMT*3C and *2 were the only variant alleles observed in this population. The total frequency of variant alleles was 2.6% and the wild type allele frequency was 97.4%. The TPMT*3B and *3A alleles were not detected. Distributions of TPMT genotype and allele frequency in Iranian populations are different from the genetic profile found among Caucasian or Asian populations. Our findings also revealed inter-ethnic differences in TPMT frequencies between different parts of Iran. This view may help clinicians to choose an appropriate strategy for thiopurine drugs and reduce adverse drug reactions such as bone marrow suppression.

Discordant patterns of mtDNA and ethno-linguistic variation in 14 Iranian Ethnic groups

BACKGROUND/AIMS

Present-day Iran has long represented a natural hub for the expansion of human genes and cultures. That being so, the overlapping of prehistoric and more recent demographic events interacting at different time scales with geographical and cultural barriers has yielded a tangled patchwork of anthropological types within this narrow area. This study aims to comprehensively evaluate this ethnic mosaic by depicting a fine-grained picture of the Iranian mitochondrial landscape.

METHODS

mtDNA variability at both HVS-I and coding regions was surveyed in 718 unrelated individuals belonging to 14 Iranian ethnic groups characterized by different languages, religions and patterns of subsistence.

RESULTS

A discordant pattern of high ethno-linguistic and low mtDNA heterogeneity was observed for the whole examined Iranian sample. Geographical factors and cultural/linguistic differences actually represented barriers to matrilineal gene flow only for the Baloch, Lur from Yasouj, Zoroastrian and Jewish groups, for which unusual reduced levels of mtDNA variability and high inter-population distances were found.

CONCLUSION

Deep rooting genealogies and endogamy in a few of the examined ethnic groups might have preserved ancestral lineages that can be representative of Proto-Indo-Iranian or prehistoric mitochondrial profiles which survived relatively recent external contributions to the Iranian gene pool.

Endothelial nitric oxide synthase VNTR (intron 4 a/b) polymorphism association with type 2 diabetes and its chronic complications

SUBJECT AND AIMS: Endothelial derived nitric oxide (eNOS) is involved in several functions playing important role in development of type 2 diabetes and insulin resistance. The aim of this study was to examine the association between eNOS intron 4 VNTR polymorphism and type 2 diabetes in an Iranian population.

METHODS

A total of 220 patients with type 2 diabetes and 96 healthy control subjects were recruited from the same area. Genotyping was performed using PCR.

RESULTS

A significant difference was found in genotype frequencies of eNOS polymorphism between patients and controls (aa+ab vs. bb p=0.02, OR 2.0 95% CI; 1.05-3.96). Also allele a frequency was significantly increased in patients with diabetes compared with controls (p=0.007, OR 2.1 95% CI; 1.19-4.08). We found that in patients with diabetic neuropathy the frequency of 'a' allele was significantly increased compared to the controls p=0.03, OR=1.8 95% CI (1.00-3.7). Both genotype and allele frequencies were significantly different between patients who were complication free compared to the controls [aa+ab vs. bb p=0.007, OR=2.6 95% CI (1.2-5.8) and p=0.001, OR=2.8 95% CI (1.4-5.9)] respectively with the a allele conferring the risk.

CONCLUSION

The association between eNOS VNTR polymorphism and T2DM seems to be stronger in patients without diabetic complications indicating diverse effect of eNOS polymorphism on diabetes and diabetic microvascular complications.

Mitochondrial DNA and Y-chromosomal stratification in Iran: relationship between Iran and the Arabian Peninsula

Modern day Iran is strategically located in the tri-continental corridor uniting Africa, Europe and Asia. Several ethnic groups belonging to distinct religions, speaking different languages and claiming divergent ancestries inhabit the region, generating a potentially diverse genetic reservoir. In addition, past pre-historical and historical events such as the out-of-Africa migrations, the Neolithic expansion from the Fertile Crescent, the Indo-Aryan treks from the Central Asian steppes, the westward Mongol expansions and the Muslim invasions may have chiseled their genetic fingerprints within the genealogical substrata of the Persians. On the other hand, the Iranian perimeter is bounded by the Zagros and Albrez mountain ranges, and the Dasht-e Kavir and Dash-e Lut deserts, which may have restricted gene flow from neighboring regions. By utilizing high-resolution mitochondrial DNA (mtDNA) markers and reanalyzing our previously published Y-chromosomal data, we have found a previously unexplored, genetic connection between Iranian populations and the Arabian Peninsula, likely the result of both ancient and recent gene flow. Furthermore, the regional distribution of mtDNA haplogroups J, I, U2 and U7 also provides evidence of barriers to gene flow posed by the two major Iranian deserts and the Zagros mountain range.

KIR gene content diversity in four Iranian populations

Killer cell immunoglobulin-like receptors (KIR) regulate natural killer cell response against infection and malignancy. KIR genes are variable in the number and type, thereby discriminating individuals and populations. Herein, we analyzed the KIR gene content diversity in four native populations of Iran. The KIR genomic diversity was comparable between Bakhtiari and Persian and displayed a balance of A and B KIR haplotypes, a trend reported in Caucasian and African populations. The KIR gene content profiles of Arab and Azeri were comparable and displayed a preponderance of B haplotypes, a scenario reported in the natives of America, India, and Australia. A majority of the B haplotype carriers of Azeri and Arab had a centromeric gene-cluster (KIR2DS2-2DL2-2DS3-2DL5). Remarkably, this cluster was totally absent from the American natives but occurred at highest frequencies in the natives of India and Australia in combination with another gene cluster at the telomeric region (KIR3DS1-2DL5-2DS5-2DS1). Therefore, despite having similar frequencies of B haplotypes, the occurrence of B haplotype-specific KIR genes, such as 2DL2, 2DL5, 3DS1, 2DS1, 2DS2, 2DS3, and 2DS5 in Azeri and Arab were substantially different from the natives of America, India, and Australia. In conclusion, each Iranian population exhibits distinct KIR gene content diversity, and the Indo-European KIR genetic signatures of the Iranians concur with geographic proximity, linguistic affinity, and human migrations.