Distinct positions of genetic and oral histories: Perspectives from India.

Over the past decade, genomic data have contributed to several insights on global human population histories. These studies have been met both with interest and critically, particularly by populations with oral histories that are records of their past and often reference their origins. While several studies have reported concordance between oral and genetic histories, there is potential for tension that may stem from genetic histories being prioritized or used to confirm community-based knowledge and ethnography, especially if they differ. To investigate the interplay between oral and genetic histories, we focused on the southwestern region of India and analyzed whole-genome sequence data from 156 individuals identifying as Bunt, Kodava, Nair, and Kapla. We supplemented limited anthropological records on these populations with oral history accounts from community members and historical literature, focusing on references to non-local origins such as the ancient Scythians in the case of Bunt, Kodava, and Nair, members of Alexander the Great's army for the Kodava, and an African-related source for Kapla. We found these populations to be genetically most similar to other Indian populations, with the Kapla more similar to South Indian tribal populations that maximize a genetic ancestry related to Ancient Ancestral South Indians. We did not find evidence of additional genetic sources in the study populations than those known to have contributed to many other present-day South Asian populations. Our results demonstrate that oral and genetic histories may not always provide consistent accounts of population origins and motivate further community-engaged, multi-disciplinary investigations of non-local origin stories in these communities.

Complete mitochondrial DNA sequence tries to settle hitherto putative history of Kayastha population of India.

OBJECTIVES: Indian caste system is unique as it has an inimitable type of class system where the social ordering is done based on birth. Within the caste system, there is a distinct endogamous population known as the Kayastha, who have had inconclusive stratification records due to unidentified historical records. METHODS: To gain a more inclusive view on the history and genetic affinities of Kayastha people, complete mitochondrial genomes from 15 individuals of a Kayastha population from North-western India have been sequenced. RESULTS: Interestingly, three novel sub-clades (U2b2a, M3d2, and M33a3b) have been identified that represent unique Kayastha motifs. CONCLUSION: The haplotype-based analysis suggests that the Kayastha population shares genetic affinities with the Indo-European and Sino-Tibetan populations found in the trans-Himalayan region. The FST based population comparison and the MDS plot indicates that Kayastha people have close maternal genetic affinity with the available genetic database of Brahmins, Kashmiris, and Tharus. The maternal genetic lineages among Kayastha population shows deep in situ origin that emerged much before settled life developed on this sub-continent. Both mtDNA and Y-chromosome markers, trace the genetic lineages of Kayastha population with Tharus, who regard themselves Kshatriya, corroborated by the oral history of the Kayasthas for their Kshatriya affiliation. It also validates genetic heritage of earliest settlers of India in both indigenous tribal and caste populations.

Glutathione S-transferase M1 and T1 null genotype frequency distribution among four tribal populations of western India.

Glutathione S transferase (GST) family is a key contributor in the detoxification mechanism of our body.Deletion of the genes within this family has been reported in the failure of detoxification system, to some extent leading to various types of cancers and other life threatening diseases. The existing data and reports on the association of null genotype of both GSTM1 and GSTT1 genes for various diseases are inconsistent. But knowledge of the polymorphic distributions of genotypes in different populations is important for investigating the risk factors in different epidemiological studies. The present study thus aims to determine thefrequency of GSTM1 and GSTT1 null genotype frequency among four tribal groups, i.e. Mina, Garasia, Damor and Saharia of western India. A comparative analysis with different tribal as well as world population has also been undertaken to have a view of its worldwide frequency distribution. Our results reveal a frequency distribution varying from 22.6% to 66.9% with respect to GSTM1gene polymorphism and from 19.1% to 33.0% with respect to GSTT1 gene in the studied populations. To the best of our knowledge this is the first report on the GSTM1and GSTT1frequency distribution among the tribal population of western India and our study shows that the Mina tribal population has the highest frequency of GSTM1.

Prevalence of malnutrition among the mising children of northeast India: a comparison between four different sets of criteria.

BACKGROUND: Prevalence of malnutrition among the children from developing countries has reached unprecedented level which can be evaluated by body mass index. AIM: This study was designed to determine the prevalence of malnutrition among the Mising children of Northeast India using four different sets of Body Mass Index references. MATERIALS AND METHODS: A cross-sectional study was performed on a population representative sample of 511 Mising children. Four different sets of Body Mass Index reference were used to define thinness as well as overweight cases. RESULTS: With the use of different references the prevalence of thinness varies from 17.18% to 27.73% among the boys and from 19.21% to 28.23% among the girls. On the other hand the prevalence of overweight varies from 1.95% to 7.81% among the boys and 1.96% to 9.41% among the girls. Reference based on United States (1971-74) survey detects sex difference in overweight. The calculated kappa values indicated a fair to almost perfect agreement between various references. CONCLUSION: Considerable prevalence of overweight despite a persistently high burden of thinness suggests existence of nutrition transition among the Mising population. Prevalence of malnutrition differs with the application of different references which warrants application of international references carefully for any potential misclassification of children.

Socioeconomic covariates and their impact on the opportunity for natural selection in a riparian tribe of Northeast India.

The intensity of natural selection correlates with various bio-social variables which influence the genetic structure of a population. In this paper it has been sought to find out the influence of variable environmental setting and economic condition on selection intensity among the Mising tribal population of Assam, Northeast India. Detailed reproductive pattern of 309 post menopausal women is obtained and a comparison has been made between different environmental as well as economic backgrounds. The impact of secular change on selection intensity has been assessed. For this study I have proposed a modified formula of Johnston & Kensinger's (1971) index for selection intensity. Crow's index of selection intensity has also been used for comparative analyses. After considering standard statistical procedure, a clear disparity of selection intensity has been noticed in terms of varying socioeconomic condition as well as habitational background. It can be concluded from the study that environmental factors act more in terms of selection pressure on infants rather than the other post natal stages.

Influence of socio-economic transition on genetic structure: a case study in Upper Assam, India.

BACKGROUND: Socio-economic transition with time offers us a way to understand the dynamics of evolution by studying the change in selection pressure. AIM: The present study aimed to explore the effect of temporal change in socio-economic conditions on the selection pattern of Sonowal Kachari, a major tribal population of Assam, north-east India, over a period of 31 years (from 1975 to 2006). It also attempts to locate the present position of the tribe in the demographic transition model on the basis of the prevalent selection pattern. SUBJECTS AND METHODS: Data on differential fertility and differential pre-reproductive mortality were collected from 155 unrelated Sonowal Kachari post-menopausal women from Dibrugarh, Upper Assam. Opportunity for natural selection was calculated on the basis of the indices put forward by Crow (I(c)) and Johnston and Kensinger (I(j)). To compute the opportunity for natural selection, different parameters such as index of selection due to infant mortality (I(m)), index of selection due to fertility (I(f)) and index of selection due to embryonic mortality (I(me)) were taken into consideration. Standard statistical techniques were applied wherever relevant. RESULTS: The different components of selection were found to be higher among the rural population than those in the urban one. Without considering the effect of regional variability, the Crow's index (I(c)) of opportunity for natural selection was found to decrease with time from 0.364 in 1975 to 0.244 in 2006. The Johnston and Kensinger index (I(j)) also decreased from 0.541 in 1975 to 0.284 in 2006. Irrespective of the methodology, the mortality component was found to decrease considerably with time without marked reduction in the fertility component. CONCLUSION: The study, within its limitations, suggests that at present the Sonowal population is experiencing a selection relaxation due to the temporal improvement of socio-economic conditions. By comparing the fertility and pre-reproductive mortality components it can be argued that the population may have been passing through the initial period of post-transitional stage, which may increase the segregation load in the population.