Indian Population Groups Research Articles

Common genetic heritage and admixture among Indian population groups as revealed by mtDNA markers

The present study determines the inter- and intra-population affinities or variations among the diverse population groups of India. The major goal of the present study was to understand the peopling of India and its role in the peopling of Southeast Asia using 11 restriction fragment length polymorphism (RFLP) mitochondrial DNA (mtDNA) markers. A total of 950 unrelated individuals be- longing to 19 population groups having varied ethnic, linguistic, and geographic backgrounds were chosen for the present study. All the studied sites, except HpaI 3592, are found to be polymorphic in the data set. High frequencies of M haplogroup are found among the South Indian populations, where- as N haplogroup is found to be high among the North Indian populations. Sub-haplogroups C and D of M are found only in the Tibeto-Burman-speaking Northeast population groups, suggesting their probable migration from Central Asia. Sub-haplogroups A and B of N are shared by both Northeast and North Indian population groups. The sub-haplogroups of M and N are absent among the South Indian and East Indian populations except the Thoti of the South India Dravidian tribe. The Northeast Indian populations exhibit the highest haplotypic diversity, whereas the South and East Indian popu- lations have the lowest haplotypic diversity. The study provides evidence for a common maternal ge- netic substratum of Indian populations with probable differential admixture from Eurasia, i.e Europe and Asia, with a decreasing trend from North to South India. Sub-haplogroups of M and N and 9 bp deletion frequency patterns suggest gene flow from East Asia to India was restricted only to Northeast India and not suggest significant movement of people from India to East Asia through Northeast India.

Association between interleukin-1 gene polymorphism and severity of chronic periodontitis in a south Indian population group

Background:Periodontitis is a bacterial disease modified by multiple factors. Interleukin-1 (IL-1) is a key regulator of the host response and a major modulator of extracellular matrix catabolism and bone resorption. It has been reported that variations in IL-1 gene are associated with increased susceptibility to periodontitis. The aims of the study were 1) to analyze the distribution of single nucleotide polymorphism of IL-1 (IL-1A-+4845 and IL-1B-+3954) and 2) to correlate the association of the composite genotype with the severity of chronic periodontitis.Materials and Methods:Sixty patients aged above 35 years were selected. Following a periodontal examination, using the clinical parameters plaque index, gingival bleeding index, probing depth, and clinical attachment loss (CAL), the selected subjects were categorized into four groups of differing disease severity based on CAL. Five milliliters of venous blood was drawn. DNA was isolated by phenol chloroform method. Amplification of IL-1A+4845 and IL-1B+3954 was done by polymerase chain reaction (PCR). Detection of genotype was done using restriction fragment length polymorphism using the enzymes FnU4HI for IL-1A and TaqI for IL-1B. The results obtained were analyzed statistically.Results:The frequencies of IL-1A-+4845 and IL-1B-+3954were significantly greater in severe periodontitis patients. The distribution of composite genotype (allele 2 of IL-1A+4845and allele 2 of IL-1B+3954) also correlated with the severity of periodontitis. Genotype-positive subjects had a higher mean bleeding index (%) when compared to genotype-negative patients. But no correlation was observed between mean plaque level among genotype-positive and -negative subjects.Conclusion:IL-1 gene polymorphism IL-1A+4845, IL-1B+3954 and composite genotype is an indicator of susceptibility to severe periodontitis in adults.

Haplotype Structures of Common Variants ofCYP2C8,CYP2C9, andADRB1Genes in a South Indian Population

In association with candidate genes, the observed trait may be due to either one of the variant alleles or the interaction of variant alleles at different loci, which are in linkage disequilibrium. The objective of this study was to investigate the baseline allele and genotype frequencies, linkage disequilibrium (LD) patterns, and haplotype structures of common variants of the CYP2C8, CYP2C9, and ADRB1 genes located on chromosome 10. Two hundred and forty-five healthy subjects were recruited from South India and were compared with the HapMap Project's population for LD pattern, allele and genotype frequencies, and haplotype structures. Genotyping was done using polymerase chain reaction-restriction fragment length polymorphism and TaqMan assay on real-time polymerase chain reaction. A significant ethnic difference was found in the LD patterns among the variant alleles between the South Indian population and other major ethnic groups, namely African, European, Chinese, and Japanese. This study established the normative allele and genotype frequencies, haplotype structure, and LD patterns of common variants of the CYP2C8, CYP2C9, and ADRB1 genes in a South Indian population (Tamilian). The data may be helpful to plan candidate gene-trait association studies in this population.

Age Estimation Using Third Molars Among Indian Juveniles: A Retrospective Analysis

Aim: To determine the age of Juvenile patients based on Third Molar Development in population belonging to Namakkal district for Forensic application. Methodology: The data was collected from the Orthopantamograms (OPG) which was regularly taken for different purposes in K.S.R institute of Dental Science & Research Outpatient Department. A retrospective analysis of these OPG's was conducted for different developmental stages given by Dimerjian et al. in 1973 for the age group of 14 to 25 years. SPSS version 10.0 was used for statistical analysis. Results: Mean Ages of the juveniles were calculated using the developmental stages of the Third molar and it was found that there was significant variation between the mean ages for different developmental stages. This implies that there exists definite ethnic variation in development of Third Molar and thus their mean ages also. Discussion: The described data may provide the third molar developmental stages and its mean age of the calcification for people belonging to Namakkal district only. Further researches are warranted in other populations as Third molar development shows definite ethnic variations, which is evident from the present study. Hence this could be used as a tool for age identification in forensic odontology for a sub group of Indian Population.

Safety and efficacy of Intacs in Indian eyes with keratoconus: An initial report

Context: In contact lens-intolerant keratoconus patients, intrastromal placement of Intacs is becoming a promising new modality of treatment. Aims: To study the safety and efficacy of implantation of microthin corneal inserts (Intacs) in Asian-Indian keratoconus patients. Settings and Design: Retrospective interventional case series, in the cornea and refractive surgery service, at a tertiary care eye hospital in South India, between May 2006 and July 2007. Materials and Methods: Intacs (Addition Technology, USA) were successfully implanted by mechanically creating tunnels, in 12 eyes of 12 keratoconus patients, who were contact lens-intolerant. The patients (mean age 25.58 years, nine male and three female) had a minimum follow-up of six months. Five patients had severe keratoconus (mean K > 53 D) and nine had central cones. Results: All patients improved or retained visual acuity. The uncorrected visual acuity (UCVA) improved from a mean value of 0.06, (SD ± 0.08) to 0.19 postoperatively (SD± 0.15) ( P = 0.01). The change in mean best corrected visual acuity (BCVA) was from 0.51, (SD ± 0.24), to 0.69, (SD ±0.00) ( P = 0.01) postoperatively. The average central keratometry reading was 52.55 D. The change in mean K from 52.84 to 49.16 and 49.15 at one and six months respectively, was statistically significant. We did not have any major intra- or early postoperative complications. Eight of 12 eyes became contact lens-tolerant post-surgery. Conclusion: The procedure of Intacs implantation appears to be safe and effective in a small group of Indian population at an intermediate follow-up.

Soft tissue cephalometric norms for a North Indian population group using Legan and Burstone analysis

Cephalometric norms are used for providing guidance to clinicians during diagnosis and treatment planning. Most classical norms are not applicable to diverse racial and ethnic population hence the purpose of this study was to establish the soft tissue norms of a North Indian population group using Legan and Burstone soft tissue analysis. The study was conducted on 60 adult subjects with esthetically pleasing profiles aged 18-25 years. Standardized lateral cephalograms were taken in a natural head position and analyzed. North Indians were found to have more convex faces, protrusive lips and acute nasolabial angles compared with Caucasians. Males had more convex faces and protrusive lips than females. This North Indian population group had significant deviations from the Caucasian standards. Considerable diversity was also found for some of the soft tissue variables in males and females.

Anthropometric and anthroposcopic analysis of different shapes of faces in group of Indian population: A pilot study

Focus of facial identification research is to isolate features that can be considered a factor of individualization. Anthropometry and Anthroposcopy have been the most important research tools in the field of forensic anthropology. These two methods of observation and data collection are made both on the living and on skeletonized human remains. Anthropometry is a systematic study of human measurements. Morphological analysis of unmeasurable features usually is the area of anthroposcopy. Hence, this study aims to assess different human faces using anthropometry and anthroposcopy. A total of 100 subjects were included in the study, prosopic index given by Martin and Saller was used to classify facial types. An anthropometric measurement was used to assess the facial proportions and anthroposcopy for facial morphology. A significant number of subjects were of hyperleptoprosopic facial type, and with a significant sexual dimorphism observed among the Indian population. Anthroposopic analysis showed common morphological features in each prosopic indices. The findings in our study may throw light on anthropometric and anthroposcopic features of Indians and help significantly in the field of forensic anthropology.

5-HTTLPR Polymorphism: Analysis in South African Autistic Individuals

The serotonin transporter promoter length polymorphism (5-hydroxytryptamine transporter length polymorphism; 5-HTTLPR) has long been implicated in autism and other psychiatric disorders. The use of selective serotonin reuptake inhibitors (SSRIs) has a positive effect on treating some symptoms of autism. The effects of these drugs vary in individuals because of the presence of the S or L allele of 5-HTTLPR. Studies performed on various autistic populations have found different allele frequencies for the L and S alleles. Allele frequencies and genotypes of the South African autistic populations (African, mixed, and Caucasian) were compared with matching South African ethnic control populations. The *S/*S genotype was found to be highly significantly associated with all the South African autistic ethnic populations. In the South African African population the *S/*S genotype was present in 7 (33%) of the autistic individuals but in none of the control subjects, yielding infinitely large odds of developing autism. The odds of developing autism with the *S/*S genotype compared to the *L /*L genotype increased 10.15-fold in the South African mixed group and 2.74-fold in the South African Caucasian population. The allele frequency of the South African autistic population was also compared with studies of other autistic populations around the world, and highly significant differences were found with the Japanese, Korean, and Indian population groups. The difference was not significant for the French, German, Israeli, Portuguese, and American groups. This is the first South African study of autistic individuals of different ethnic backgrounds that shows significant differences in allele and genotype frequencies of 5-HTTLPR. The results of this study open new avenues for investigating the role of transmission of the L and S alleles in families with autism in South Africa.

5-HTTLPR Polymorphism: Analysis in South African Autistic Individuals

The serotonin transporter promoter length polymorphism (5-hydroxytryptamine transporter length polymorphism; 5-HTTLPR) has long been implicated in autism and other psychiatric disorders. The use of selective serotonin reuptake inhibitors (SSRIs) has a positive effect on treating some symptoms of autism. The effects of these drugs vary in individuals because of the presence of the S or L allele of 5-HTTLPR. Studies performed on various autistic populations have found different allele frequencies for the L and S alleles. Allele frequencies and genotypes of the South African autistic populations (African, mixed, and Caucasian) were compared with matching South African ethnic control populations. The *S/*S genotype was found to be highly significantly associated with all the South African autistic ethnic populations. In the South African African population the *S/*S genotype was present in 7 (33%) of the autistic individuals but in none of the control subjects, yielding infinitely large odds of developing autism. The odds of developing autism with the *S/*S genotype compared to the *L/*L genotype increased 10.15-fold in the South African mixed group and 2.74-fold in the South African Caucasian population. The allele frequency of the South African autistic population was also compared with studies of other autistic populations around the world, and highly significant differences were found with the Japanese, Korean, and Indian population groups. The difference was not significant for the French, German, Israeli, Portuguese, and American groups. This is the first South African study of autistic individuals of different ethnic backgrounds that shows significant differences in allele and genotype frequencies of 5-HTTLPR. The results of this study open new avenues for investigating the role of transmission of the L and S alleles in families with autism in South Africa.

Lower Dorsal and Lumbar Pedicle Morphometry in Indian Population

STUDY DESIGN.: Prospective, computer aided pedicle morphometric data measurements obtained from computed tomography (CT) scan of lower thoracic (T9-T12) and lumber vertebrae in a large group of Indian population. OBJECTIVES.: Measurement on CT scan of the surgically relevant parameters of transverse pedicle isthmus width, transverse pedicle angle, and depth to anterior cortex along the midline axis and the pedicle axis by Computer software aid in a large sample of Indian population. To compare the results with those of similar studies of Western and Indian population in literature by other methods and to deduce safety parameters for pedicular screw placements in these areas. SUMMARY OF BACKGROUND DATA.: Although differences have been reported in literature between various ethnic groups, most studies reported are for white populations and Indian studies are few. The Indian studies have had small sample size, and been done on patients with preexisting spinal disorder or cadavers and by manual data measurements. To the authors' knowledge, the present study is the largest published for patients from the Indian subcontinent and only using computer software aided measurements. METHODS.: CT scans of the lower thoracic and lumbosacral spine of patients free from spinal disorders from the Indian subcontinent were reviewed. We analyzed a total of 450 vertebrae in 50 consecutive patients. Parameters recorded were transverse pedicle isthmus width, transverse pedicle angle, and depth to anterior cortex along the midline axis and the pedicle axis with help of computer software. RESULTS.: The mean transverse pedicle isthmus width was least at the T9 level (5.65 mm). Majority of pedicles at thoracic level had diameter over 5 mm T9 (94%), T10 (100%), T11 (96%), T12 (100%). At lumber all had diameters over 7 mm with wide range at upper levels. The mean transverse pedicle angle faced laterally at thoracic vertebrae with exception of T9. In lumber area, all were medially directed with maximum at L5 and least at L1. The depth to the anterior cortex was more along the pedicle axis at all levels except T11 and T12. CONCLUSION.: Significant differences exist between the pedicles of Indian and white populations. It is suggested that preoperative software-based morphometric data should be collected if possible for preoperative planning of pedicle implant placement and sizes to avoid inadvertent complications. Further, data from study can be used as a guide for implant size, intraoperative placement trajectory at lower thoracic and lumber vertebrae pedicles.

Significance of Genome-Wide Association Studies in Molecular Anthropology

The successful advent of a genome-wide approach in association studies raises the hopes of human geneticists for solving a genetic maze of complex traits especially the disorders. This approach, which is replete with the application of cutting-edge technology and supported by big science projects (like Human Genome Project; and even more importantly the International HapMap Project) and various important databases (SNP database, CNV database, etc.), has had unprecedented success in rapidly uncovering many of the genetic determinants of complex disorders. The magnitude of this approach in the genetics of classical anthropological variables like height, skin color, eye color, and other genome diversity projects has certainly expanded the horizons of molecular anthropology. Therefore, in this article we have proposed a genome-wide association approach in molecular anthropological studies by providing lessons from the exemplary study of the Wellcome Trust Case Control Consortium. We have also highlighted the importance and uniqueness of Indian population groups in facilitating the design and finding optimum solutions for other genome-wide association-related challenges.

Health-related quality of life of elderly living in the rural community and homes for the elderly in a district of India

The present investigation aimed to assess the health-related QoL (HRQoL) of elderly people living in two settings: (i) rural community and (ii) homes for the elderly in a district of South India. The data are drawn from elderly (>60 years of age) sampled from both settings. The short form 36-item health survey (SF-36) was administered to all respondents. The average scores for several domains, including total physical health, total mental health and overall health (total SF-36 score) were around 50, which can be interpreted as a moderate level of health-related QoL. Residents living in a home for the elderly scored better in all domains except for role-physical and role-emotional. Though univariate analysis revealed some associations between characteristics of elderly SF-36 scores, the multiple regression analysis indicated that working status yields a significant but negative coefficient for total SF-36 score among community dwelling elderly. The elderly report that their lives are better when they are staying in homes for the elderly. Hence, despite the socio-economic conditions, provision of a better and conducive environment by setting up more charity-based homes for the elderly may be one of the options for relative betterment of the QoL of the elderly, particularly those who are socially and economically deprived. Finally, the study warrants the need of normative values of SF-36 for various population groups in India.

Evaluation of 21 Y-STRs for population and forensic studies

In the present study we evaluated the applicability for forensic and evolutionary studies of 21 Y-STR loci (DYS437, DYS447, DYS448, DYS449, DYS456, DYS481, DYS504, DYS510, DYS518, DYS532, DYS536, DYS542, DYS552, DYS562, DYS576, DYS587, DYS612, DYS626, DYS644, DYS710, and Y-GATA-H4). Allele sequence analysis, allele diversity, gene diversity, allele frequency spectrum, discrimination capacity and informativeness for assignment were studied in European English, Asian Indian and Xhosa population groups sampled in South Africa. Seven loci showed size homoplasy. Individuals with mixed ancestry were identified using a statistical method for population assignment and a phylogenetic network. In comparison to our previous minimal haplotype data for the same population groups these loci showed significant increase in discrimination capacity (overall, from 0.773 to 0.958).

Singapore Genome Variation Project: A haplotype map of three Southeast Asian populations

The Singapore Genome Variation Project (SGVP) provides a publicly available resource of 1.6 million single nucleotide polymorphisms (SNPs) genotyped in 268 individuals from the Chinese, Malay, and Indian population groups in Southeast Asia. This online database catalogs information and summaries on genotype and phased haplotype data, including allele frequencies, assessment of linkage disequilibrium (LD), and recombination rates in a format similar to the International HapMap Project. Here, we introduce this resource and describe the analysis of human genomic variation upon agglomerating data from the HapMap and the Human Genome Diversity Project, providing useful insights into the population structure of the three major population groups in Asia. In addition, this resource also surveyed across the genome for variation in regional patterns of LD between the HapMap and SGVP populations, and for signatures of positive natural selection using two well-established metrics: iHS and XP-EHH. The raw and processed genetic data, together with all population genetic summaries, are publicly available for download and browsing through a web browser modeled with the Generic Genome Browser.

Characterization of the highly discriminatory loci DYS449, DYS481, DYS518, DYS612, DYS626, DYS644 and DYS710

During the study of genetic diversity at non-core Y-STRs in South African population groups, we identified loci with high discrimination capacity. In this study we present a detailed account of the allele diversity, allele sequence data, gene diversity, allele frequency spectrum and informativeness for assignment in the European English, Asian Indian and Xhosa population groups at loci DYS449, DYS481, DYS518, DYS612, DYS626, DYS644 and DYS710. The suitability of these loci for forensic, genealogical and evolutionary studies is discussed, and nomenclature for loci DYS518, DYS612, DYS626 and DYS644 is suggested.

Obesity and Blood Pressure Variations among the Bengali Kayastha Population of North Bengal, India

Obesity is defined either by increased waist circumference (WC), waist-height ratio (WHtR), conicity index (CI) waist-hip ratio (WHR) and/or body mass index (BMI). As individuals from the developing countries consume more quantities of high-energy food and have less physical activity, the number of overweight and obese individuals increase. Obesity has a detrimental effect on blood pressure and increases cardiovascular events. One important issue that is currently assuming relevance in studies involving blood pressure and anthropometric parameters is the mean arterial pressure (MAP). There exists limited data on such issues among different Indian population and caste groups. This cross sectional study was carried out during the period October-December 2007 in four localities of Alipurduar town (Alipurduar sub-division, Jalpaiguri district, West Bengal, India). A total of 150 individuals (75 males and 75 females) agreed to take part in the same. Blood pressure (SBP and DBP) was measured on left arm by auscultatory method using a mercury sphygmomanometer. The anthropometric measurements have been recorded using standard procedures. The male individuals show higher means with respect to the anthropometric measurements and the blood pressure values, as compared to the females. The prevalence of hypertension was almost 50.00%. Obesity accounted for 80.00% of the individuals. Using step-wise regression analysis, it has been observed that all the anthropometric parameters play a role in blood pressure. It can be observed that the Bengali Kayastha population of Alipurduar town has a high prevalence of obesity. Moreover, BMI, WC and WHtR have strong correlations with DBP and MAP.

Genetic variation of polymorphic NOS STR locus in ten Indian population groups

The genotyping of 313 random individuals belonging to ten different population groups from three different states of India was performed for polymorphic pentanucleotide repeat present in the 5'-flanking region of nitric oxide synthase gene (NOS2A) to study the effect of geographical and linguistic affiliations on the genetic affinities among these groups. Likelihood ratio tests showed that all the ten populations for this locus were in Hardy Weinberg equilibrium. Eleven different alleles ranging from 7 repeat to 17 repeats and 46 different genotypes were observed. The observed and the expected heterozygosity ranged from 0.72-0.94 and 0.84-0.89, respectively. The discriminating power of this locus is > or = 0.86 and the polymorphism information content of this locus in ten population groups ranged from 0.80 to 0.85. High PIC, PD and PE value of this STR showed this marker to be informative and can be used for DNA typing and population studies. The eight populations from Kerala showed a lower GST value of 0.016 compared to the GST of ten populations (G(ST) = 0.019), thereby showing that the populations from the same state showed higher genetic proximity probably due to linguistic and geographical proximity between them.

Safety and efficacy of Intacs in Indian eyes with keratoconus: An initial report

ContextIn contact lens-intolerant keratoconus patients, intrastromal placement of Intacs is becoming a promising new modality of treatment.AimsTo study the safety and efficacy of implantation of microthin corneal inserts (Intacs) in Asian-Indian keratoconus patients.Settings and DesignRetrospective interventional case series, in the cornea and refractive surgery service, at a tertiary care eye hospital in South India, between May 2006 and July 2007.Materials and MethodsIntacs (Addition Technology, USA) were successfully implanted by mechanically creating tunnels, in 12 eyes of 12 keratoconus patients, who were contact lens-intolerant. The patients (mean age 25.58 years, nine male and three female) had a minimum follow-up of six months. Five patients had severe keratoconus (mean K > 53 D) and nine had central cones.ResultsAll patients improved or retained visual acuity. The uncorrected visual acuity (UCVA) improved from a mean value of 0.06, (SD ± 0.08) to 0.19 postoperatively (SD± 0.15) (P= 0.01). The change in mean best corrected visual acuity (BCVA) was from 0.51, (SD ± 0.24), to 0.69, (SD ±0.00) (P = 0.01) postoperatively. The average central keratometry reading was 52.55 D. The change in mean K from 52.84 to 49.16 and 49.15 at one and six months respectively, was statistically significant. We did not have any major intra- or early postoperative complications. Eight of 12 eyes became contact lens-tolerant post-surgery.ConclusionThe procedure of Intacs implantation appears to be safe and effective in a small group of Indian population at an intermediate follow-up.

Comparison of observed body retention of uranium in natural condition in an average Indian adult with the values predicted by the ICRP biokinetic model

The daily intake of natural uranium and its contents in the lungs, skeleton, liver and kidney of an Indian adult population group was estimated using radiochemical neutron activation analysis (RNAA). These data on daily intake (through inhalation and ingestion) were used to compute the uranium contents in the lungs and other systemic organs such as the skeleton, liver and kidney, using the new human respiratory tract model (HRTM) and the new biokinetic model of uranium. The theoretically computed uranium contents in the lungs, skeleton, liver and kidney of an average Indian adult are 1.16, 1.96, 0.07 and 0.04 microg, respectively, and the corresponding experimentally measured values are 1.23 (1.76), 2.92 (2.5), 0.07 (1.76) and 0.19 (1.47) microg in an urban population group living in Mumbai. The values given in parentheses are geometric standard deviation (GSD). It is seen that the measured uranium contents in the lungs, skeleton and liver agree very well with the corresponding computed values, but the measured value for the kidney is observed to be on the higher side of the computed value. However, in view of many uncertainties, the overall agreement between the measured and the computed values can be considered to be good. Therefore, the result from this study can be taken as a validation of the new biokinetic model of uranium in Indian conditions.

Genetic Affinities of the Siddis of South India: An Emigrant Population of East Africa

Historical records indicate that the Portuguese brought the African Siddis to Goa, India, as slaves about 500 years ago. Subsequently, the Siddis moved into the interior regions of the state of Karnataka, India, and have remained there ever since. Over time the Siddis have experienced considerable cultural changes because of their proximity to neighboring population groups. To understand the biological consequences of these changes, we studied the Siddis to determine the extent of genetic variation and the contributions from the African, European, and Indian ancestral populations. In the present study we typed the Siddis for 20 polymorphic serological, red cell, and Alu insertion-deletion loci. The overall pattern of phenotype (and genotype) distribution is in accordance with Hardy-Weinberg expectations. Considering the ethnohistorical records and the availability of secondary-source genetic data, we used two data sets in the analysis: one comprising eight serological and red cell enzyme markers with eight population groups and another comprising six Alu insertion-deletion markers with seven tribal groups of South India. The dendrograms generated from these two data sets on the basis of genetic distance analysis between the selected populations of African, European, and Indian descent reveals that the Siddis are closer to the Africans than they are to the South Indian populations. Genetic admixture analysis using a dihybrid model (19 loci) and a trihybrid model (10 loci and 8 loci) shows that the predominant influence comes from the Africans, a lesser contribution from the South Indians, and a slight contribution from the Portuguese. Thus the original composition of the African genes among the Siddis has been diluted to some extent by the contribution from southern Indian population groups. There is no nonrandom association of alleles among a set of 10 genetic marker systems considered in the present study. The demonstration of genetic homogeneity of the Siddis, despite their admixed origin, suggests the utility of this population for genetic and epidemiological studies.