The influence of natural barriers in shaping the genetic structure of Maharashtra populations.

BACKGROUND: The geographical position of Maharashtra state makes it rather essential to study the dispersal of modern humans in South Asia. Several hypotheses have been proposed to explain the cultural, linguistic and geographical affinity of the populations living in Maharashtra state with other South Asian populations. The genetic origin of populations living in this state is poorly understood and hitherto been described at low molecular resolution level. METHODOLOGY/PRINCIPAL FINDINGS: To address this issue, we have analyzed the mitochondrial DNA (mtDNA) of 185 individuals and NRY (non-recombining region of Y chromosome) of 98 individuals belonging to two major tribal populations of Maharashtra, and compared their molecular variations with that of 54 South Asian contemporary populations of adjacent states. Inter and intra population comparisons reveal that the maternal gene pool of Maharashtra state populations is composed of mainly South Asian haplogroups with traces of east and west Eurasian haplogroups, while the paternal haplogroups comprise the South Asian as well as signature of near eastern specific haplogroup J2a. CONCLUSIONS/SIGNIFICANCE: Our analysis suggests that Indian populations, including Maharashtra state, are largely derived from Paleolithic ancient settlers; however, a more recent (∼10 Ky older) detectable paternal gene flow from west Asia is well reflected in the present study. These findings reveal movement of populations to Maharashtra through the western coast rather than mainland where Western Ghats-Vindhya Mountains and Narmada-Tapti rivers might have acted as a natural barrier. Comparing the Maharastrian populations with other South Asian populations reveals that they have a closer affinity with the South Indian than with the Central Indian populations.

Deciduous dental morphology and the biological affinities of a late Chalcolithic skeletal series from western India.

Morphological variations of the dental crown and roots provide valuable data for determining the genetic affinities and evolutionary adaptedness of prehistoric human skeletal populations. This paper documents morphological variations of a sample of deciduous teeth from the late Chalcolithic farming village of Inamgaon (1600-700 B.C.) in western India. Hanihara's (1963) grading system of deciduous dental traits was employed in assessing the degree of expression of shovel-shape of incisors, cusp number of upper and lower first molars, hypocone variation, Carabelli's trait, cusp number of lower second molars and the protostylid. Turner's (1970) classification was used to determine presence and size of accessory cusps: entoconulid (C-6) and metaconulid (C-7). Comparative evaluation of the Inamgaon deciduous dental data is hampered by the absence of data for dental features of living and prehistoric South Asian populations. Many of the traits observed in the Inamgaon series exhibit a frequency of occurrence intermediate between figures characteristic of the "Mongoloid" dental complex and the "Caucasoid" dental complex.

Epidemiology of enamel hypoplasia in deciduous teeth: explaining variation in prevalence in western India.

This study is based on seven samples of school children (n = 516) from rural (five groups) and urban (two groups) settings in western Maharashtra, India. Height and weight were recorded for each subject. Intra-oral observation of the labial surface of maxillary and mandibular anterior teeth was conducted with a low power (3x) illuminated hand lens. Presence of enamel hypoplasia was recorded on a dental chart by drawing the size and location of the defect on the affected tooth. Data analysis was conducted in two stages: 1) Enamel hypoplasia (EH) prevalence was analyzed by percentage of teeth and by percentage of individuals affected for the composite sample and independently for each study group and 2) an assessment of the relationship between anthropometric variables (height and weight), socio-economic status (SES), and localized hypoplasia of primary canines (LHPC; Skinner, 1986) was evaluated using multiple linear regression analysis. EH was observed less often in deciduous incisors (0.2% in di(2) to 2.5% in di(2)) than in deciduous canines (dc). Mandibular dc were affected with the greatest frequency (23.1%, tooth count). The overall individual count prevalence of dc hypoplasia (LHPC) is 26.2% (134/511) for all village samples and sexes combined. Difference in LHPC frequency by sex is non-significant, with males (24.7%, 70/284) and females (28.2%, 64/227) exhibiting nearly equal values. Significant inter-group variation in LHPC prevalence was documented among the seven groups, and the range of LHPC prevalence the among living groups exceeds variability in LHPC among four prehistoric Chalcolithic skeletal series of the Deccan Plateau. Multiple regression analysis revealed no significant relationship between height-for-age or weight-for-age in four school samples (two urban/two rural), but a significant association between stature and LHPC was found for three rural endogamous groups. Children with LHPC were significantly shorter by 1.5 cm than children who lacked the defect after controlling for differences in age. While the association between low birth weight and EH is strong and well documented clinically, the association between childhood stature and LHPC is more variable across groups and may reflect inter-group variation in the duration and intensity of environmental stress.