Biology subjects

Mustak, M. S.

Publications and source records attributed to Mustak, M. S..

8 recordsLinked to original sources

bioRxiv2026

South Asian Maternal Lineage haplogroup R30 Provides Phylogenetic Evidence of human dispersal across South Asia

South Asia is central to debates on early human dispersals, particularly the Out of Africa model and Eurasian colonization. Studies of M haplogroups have been used to support both Northern and Southern route hypotheses, but current archaeological and genetic evidence in the region remains contradictory. In the present work, we find that in addition to haplogroup M lineages, a few R lineages exhibit ancient, locally rooted variation, with R30 being one of the widespread haplogroup of R lineages across South Asia. To better understand South Asian demographic history, we investigated the phylogeographic distribution of haplogroup R30, an indigenous lineage. We used 190 complete modern and ancient sequences from diverse mainland and island populations including incorporation of 44 newly generated sequences which enabled the refinement of the R30 phylogeny and the identification of a novel basal lineage, R30c. Bayesian and {rho}-based age estimates suggest that R30 originated in the Indian subcontinent ~50 kya. Early diversification likely occurred in Northern India, giving rise to R30b (~44 kya), while R30a and R30c differentiated primarily in Southern India. Several subclades of haplogroup R30 exhibit strong signatures of founder effects, particularly among the language isolate Vedda of Sri Lanka, Uru Kurumban of Southern India, and the populations of the Lakshadweep archipelago. Bayesian skyline analyses indicate long-term demographic stability followed by rapid lineage expansion ~20 kya and more recent declines consistent with localised drift and relatively recent founder events. The presence of early-diverging R30 lineages in Thailand and Indonesia further supports long-term connections between South and Southeast Asia. Overall, archaeological and genetic evidence point towards the multiple migrations for South Asia colonizations.

evolutionary biology↗

bioRxiv2024

Maternal genetic affinities of Konkani population in the southwest coast of India

Ko[n]kan region on the west coast of India is a hotspot of culture, folklore and ethnolinguistic diversity. The genetic landscape of this region remains understudied. The present study features Ko[n]kan[i] population residing along the Ko[n]kan Malabar coast. We have sequenced complete mitogenomes of 85 and the hypervariable region of 210 Ko[n]kan[i] individuals to understand the maternal gene pool of this region. Comparative analysis of the over 5000 mitogenomes revealed that the Ko[n]kan[i] population clustered at a convergence point on the PCA plot, presumably due to a diverse maternal gene pool with both autochthonous and West Eurasian components. A distinct clustering pattern was observed within the subgroups of S[a]rasvata and non-S[a]rasvata Ko[n]kan[i] groups, indicating unique ancestral maternal lineages in them. This distinction is majorly due to the N macrohaplogroup lineages found in this population. We observe low haplotype and nucleotide diversity in Citrapur S[a]rasvata Brahmins (CSB), R[a]j[a]pur S[a]rasvata Brahmins (RSB), Kh[a]rvi and Kudubi compared to Gauda S[a]rasvata Brahmins (GSB) and Roman Catholics. The assimilation of both pre and post Last Glacial Maximum (LGM) haplogroups like M57, M36, M37, M3, M30, R8 and U2 in the Ko[n]kan[i] population suggests active movement and settlement along the Ko[n]kan region on the west coast of India since the Late Pleistocene through the Holocene.

genetics↗

bioRxiv2024

Y chromosome STR variation reveals traditional occupation based population structure in India

Earlier models of grouping Indian populations were based on language families, social stratification and geographical location. Such grouping system has often resulted in oversimplification of ancestry inferences. Moreover, we do not find many studies focused on studying the variation within these groups and the role of past demographic events in shaping them. We analysed the Y-chromosome Short Tandem Repeats haplotypes from 8153 males from India and Eurasia to explore the impact of Holocene migration on the Indian gene pool. We used haplotype variation and date estimates to understand the characteristics of each haplogroup with respect to the different grouping models. Our findings show that the Neolithic agricultural expansion has had a strong influence in shaping the male gene pool of the Indian subcontinent. Haplogroups F, L and R1a contribute greatly towards stratifying Indian populations as hunter-gatherer related, farming-related and priestly groups respectively. Although the caste system enforced endogamy, a traditional occupation based admixture existed since the Neolithic times. Dispersal of haplogroup L from the Near East played a major role in the formation of an agriculturist population that formed an intermediary between the primitive tribes and the R1a-rich priestly group. This study shows that the frequency of R1a in the hunter-gatherer tribes (1.5%) is much lower than previously reported based on other models of population clustering.

genetics↗

bioRxiv2024

Novel 4,400-year-old ancestral component in a tribe speaking a Dravidian language

Research has shown that the present-day population on the Indian subcontinent derives its ancestry from at least three components identified with pre-Indo-Iranian agriculturalists once inhabiting the Iranian plateau, pastoralists originating from the Pontic-Caspian steppe and ancient hunter-gatherer related to the Andamanese Islanders. The present-day Indian gene pool represents a gradient of mixtures from these three sources. However, with more sequences of ancient and modern genomes and fine structure analyses, we can expect a more complex picture of ancestry to emerge. In this study, we focus on Dravidian linguistic groups to propose a fourth putative source which may have branched out from the basal Middle Eastern component that gave rise to the Iranian plateau farmer related ancestry. The Elamo-Dravidian theory and the linguistic phylogeny of the Dravidian family tree provide chronological fits for the genetic findings presented here. Our findings show a correlation between the linguistic and genetic lineages in language communities speaking Dravidian languages when they are modelled together. We suggest that this source, which we shall call Proto-Dravidian ancestry, emerged around the dawn of the Indus Valley civilisation. This ancestry is distinct from all other sources described so far, and its plausible origin not later than 4,400 years ago on the region between the Iranian plateau and the Indus valley supports a Dravidian heartland before the arrival of Indo-European languages on the Indian subcontinent. Admixture analysis shows that this Proto-Dravidian ancestry is still carried by most modern inhabitants of the Indian subcontinent other than the tribal populations. This momentous finding underscores the importance of population-specific fine structure studies. We also recommend informed sampling strategies for biobanks and to avoid oversimplification of ancestral reconstruction. Achieving this requires interdisciplinary collaboration.

evolutionary biology↗

bioRxiv2022

Integrating genetic and oral histories of Southwest Indian populations

Over the past decade, genomic data has 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 158 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 Greats 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 Andaman Islanders. 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.

genetics↗

bioRxiv2022

Genetic affinities and adaptation of the South West coast populations of India

Evolutionary event has not only transformed the genetic structure of human populations but also associated with social and cultural transformation. South Asian populations were formed as a result of such evolutionary events of migration and admixture of genetically and culturally distinct groups. Most of the genetic studies pointed to large-scale admixture event between Ancestral North Indian (ANI) and Ancestral South Indian (ASI) groups, also additional layers of recent admixture. In the present study we have analyzed 213 individuals inhabited in South West coast India with traditional warriors and feudal lord status and historically associated with recent migrations events and possible admixture with Indo-Scythians, Saka, Huns and Kushans, whose genetic links are still missing. Analysis of autosomal SNP markers suggests that these groups possibly derived their ancestry from some groups of North West India having additional Middle Eastern genetic component and also their separation history suggests very early separation from North West Indian and Gangetic plain Indo-Europeans during late bronze or Iron age, most probably following central India and Godavari basin to South West coast. Higher distribution of west Eurasian mitochondrial haplogroups also points to admixture through maternal lineage. Selection screen using genome wide genealogy approach revealed genetic signatures related to their long-term coastal food habits. Thus, our study suggests that the South West coastal groups with traditional warriors and feudal lords status are of a distinct lineage compared to Dravidian and Gangetic plain Indo-Europeans and are remnants of very early migrations from North West India following Godavari basin to Karnataka and Kerala.

genetics↗

bioRxiv2022

Seasonal dynamics and polyphenism of butterfly communities in the coastal plains of central Western Ghats, India

Long-term socioeconomic progress requires a healthy environment/ecosystem, but anthropogenic activities cause environmental degradation and biodiversity loss. Constant ecological monitoring is therefore necessary to assess the state of biodiversity and ecological health. However, baseline data is lacking even for ecologically sensitive regions such as the Western Ghats. We looked at the seasonality and polyphenism of butterflies of the central Western Ghats to get baseline population patterns on these charismatic taxa. We recorded 43118 individuals (175 species) using fortnightly time-constrained counts for two consecutive years, and found the peak abundance (49% of the total individuals) in post-monsoon period (Oct to Jan). The seasonal abundance was correlated with the overall increase in species richness. Habitat differences were stronger than seasonality as samples clustered based on sites. Several species also displayed polyphenism with distinct distributions of wet and dry season forms. Seasonal equitability and indicator species analysis showed distinct inter-species differences in seasonality patterns. This work provides key baseline data on the seasonal dynamics of butterflies of the Western Ghats in the context of climate change and conservation, and will help in future monitoring of this ecologically sensitive region using butterflies.

ecology↗

bioRxiv2021

Ecological interactions: Patterns of host utilization by tropical butterflies

Structural complexity of ecological networks facilitate the functional robustness of natural ecosystems. Threatened by the human actions such as habitat destruction and climate change, species may be more or less prone to ecological perturbations depending on the nature of their interactions. We examined the host network of tropical butterflies from the Indian region to see their level of interconnectedness. We manually curated larval host utilization data for 1053 butterflies of India. About 98.8% of species that occur pan-India and 90.6% of species exclusive to the Western Ghats had known hosts whereas it was only 25.9% for species exclusive to north-east India. There were 2589 unique butterfly-host interactions comprising 519 butterfly species and their 1091 known hosts. However, nearly 30% of the species had only single hosts. The Fabaceae and Poaceae were the key host families that accounted for 32.8% of the interactions. There were clear host preferences and monocots hosted disproportionately more butterfly species and interactions. Vanessa cardui had at least 39 known hosts while Ochlandra travancorica supported 19 butterfly species. There were 2693 species-pairs and 4226 interactions among 469 butterflies due to shared hosts. Many butterfly species that have relatively few/unique hosts might be vulnerable in the context of habitat destruction and climate change. This work has great relevance to the ecology and conservation of butterflies in India.

ecology↗