Evolutionary Biology Group
Evolutionary Biology Group
Chaubey G.,Evolutionary Biology Group
European Journal of Human Genetics | Year: 2017
The Gond comprise the largest tribal group of India with a population exceeding 12 million. Linguistically, the Gond belong to the Gondi–Manda subgroup of the South Central branch of the Dravidian language family. Ethnographers, anthropologists and linguists entertain mutually incompatible hypotheses on their origin. Genetic studies of these people have thus far suffered from the low resolution of the genetic data or the limited number of samples. Therefore, to gain a more comprehensive view on ancient ancestry and genetic affinities of the Gond with the neighbouring populations speaking Indo-European, Dravidian and Austroasiatic languages, we have studied four geographically distinct groups of Gond using high-resolution data. All the Gond groups share a common ancestry with a certain degree of isolation and differentiation. Our allele frequency and haplotype-based analyses reveal that the Gond share substantial genetic ancestry with the Indian Austroasiatic (ie, Munda) groups, rather than with the other Dravidian groups to whom they are most closely related linguistically.European Journal of Human Genetics advance online publication, 1 February 2017; doi:10.1038/ejhg.2016.198. © 2017 Macmillan Publishers Limited, part of Springer Nature.
Metspalu M.,Evolutionary Biology Group |
Metspalu M.,University of Tartu |
Romero I.G.,University of Cambridge |
Yunusbayev B.,Evolutionary Biology Group |
And 22 more authors.
American Journal of Human Genetics | Year: 2011
South Asia harbors one of the highest levels genetic diversity in Eurasia, which could be interpreted as a result of its long-term large effective population size and of admixture during its complex demographic history. In contrast to Pakistani populations, populations of Indian origin have been underrepresented in previous genomic scans of positive selection and population structure. Here we report data for more than 600,000 SNP markers genotyped in 142 samples from 30 ethnic groups in India. Combining our results with other available genome-wide data, we show that Indian populations are characterized by two major ancestry components, one of which is spread at comparable frequency and haplotype diversity in populations of South and West Asia and the Caucasus. The second component is more restricted to South Asia and accounts for more than 50% of the ancestry in Indian populations. Haplotype diversity associated with these South Asian ancestry components is significantly higher than that of the components dominating the West Eurasian ancestry palette. Modeling of the observed haplotype diversities suggests that both Indian ancestry components are older than the purported Indo-Aryan invasion 3,500 YBP. Consistent with the results of pairwise genetic distances among world regions, Indians share more ancestry signals with West than with East Eurasians. However, compared to Pakistani populations, a higher proportion of their genes show regionally specific signals of high haplotype homozygosity. Among such candidates of positive selection in India are MSTN and DOK5, both of which have potential implications in lipid metabolism and the etiology of type 2 diabetes. © 2011 The American Society of Human Genetics.
PubMed | Evolutionary Biology Group, National Cancer Center, RIPAS Hospital, University of Cambridge and 3 more.
Type: Journal Article | Journal: European journal of human genetics : EJHG | Year: 2016
The history of human settlement in Southeast Asia has been complex and involved several distinct dispersal events. Here, we report the analyses of 1825 individuals from Southeast Asia including new genome-wide genotype data for 146 individuals from three Mainland Southeast Asian (Burmese, Malay and Vietnamese) and four Island Southeast Asian (Dusun, Filipino, Kankanaey and Murut) populations. While confirming the presence of previously recognised major ancestry components in the Southeast Asian population structure, we highlight the Kankanaey Igorots from the highlands of the Philippine Mountain Province as likely the closest living representatives of the source population that may have given rise to the Austronesian expansion. This conclusion rests on independent evidence from various analyses of autosomal data and uniparental markers. Given the extensive presence of trade goods, cultural and linguistic evidence of Indian influence in Southeast Asia starting from 2.5kya, we also detect traces of a South Asian signature in different populations in the region dating to the last couple of thousand years.
PubMed | Armenian National Academy of Sciences, CSIR - Central Electrochemical Research Institute, RIPAS Hospital, Gladstone and 34 more.
Type: Journal Article | Journal: Nature | Year: 2016
Here we report the Simons Genome Diversity Project data set: high quality genomes from 300 individuals from 142 diverse populations. These genomes include at least 5.8 million base pairs that are not present in the human reference genome. Our analysis reveals key features of the landscape of human genome variation, including that the rate of accumulation of mutations has accelerated by about 5% in non-Africans compared to Africans since divergence. We show that the ancestors of some pairs of present-day human populations were substantially separated by 100,000 years ago, well before the archaeologically attested onset of behavioural modernity. We also demonstrate that indigenous Australians, New Guineans and Andamanese do not derive substantial ancestry from an early dispersal of modern humans; instead, their modern human ancestry is consistent with coming from the same source as that of other non-Africans.
News Article | December 16, 2015
A life reconstruction of Morelladon is shown in this illustration provided by Carlos de Miguel Chaves. Scientists on December 16, 2015 announced the discovery near the town of Morella in Spain's Castellon Province of the fossil remains of a medium-sized dinosaur they named Morelladon, a four-legged herbivore that measured 6 meters (20 feet) long. Protruding from its back was a series of bony spines that formed the sail-like structure that stood about two feet (60 cm) tall. REUTERS/Carlos de Miguel Chaves/Handout via Reuters More WASHINGTON (Reuters) - Along a lush river delta in what is now northeastern Spain, a herd of dinosaurs munched on ferns and conifers similar to modern-day cypresses 125 million years ago. These creatures stood out from the others in this Cretaceous Period landscape by virtue of the unusual sail-like structure on their backs, and experts today can only hypothesize about its function. Scientists announced on Wednesday the discovery near the town of Morella in Spain's Castellón Province of the fossil remains of a medium-sized dinosaur they named Morelladon, a four-legged herbivore that measured 6 meters (20 feet) long. Protruding from its back was a series of bony spines that formed the sail-like structure that stood about 2 feet (60 cm) tall. "The sail could help in heat exchange - thermoregulation - focused on releasing excess body heat into the environment, like the ears of the modern-day elephants, or as a storage place for fat to be used during periods of low food supply," said paleontologist Fernando Escaso of the National University of Distance Education's Evolutionary Biology Group in Spain. The structure also could have served a display role in attracting mates, Escaso added. Escaso noted that sail-like structures appeared periodically in the evolutionary history of vertebrates, often in animal groups not closely related to one another. Another plant-eating dinosaur called Ouranosaurus with similarities to Morelladon lived about the same time in Africa. The biggest sail-backed creature was Spinosaurus, which lived a semi-aquatic lifestyle 95 million years ago in Africa. At 50 feet long (15 metres) and 7 tons, it was the biggest dinosaur predator on record, larger even than Tyrannosaurus rex. Millions of years before the rise of the dinosaurs, there were other sail-backed creatures including the carnivorous reptile Arizonasaurus, the amphibian Platyhystrix and the distant mammal relatives Dimetrodon and Edaphosaurus. Morelladon is known from a partial skeleton including the spines, other vertebrae, pelvic bones, a thigh bone and teeth. Northeastern Spain during Morelladon's time alternated between wet and dry periods, with strong temperature variations ranging from 40 degrees Fahrenheit (4 Celsius) to about 104 F (40 C). Escaso said the main predator in the area was Baryonyx, a relative of Spinosaurus, and there were other plant-eating dinosaurs around as well as crocodilians and the flying reptiles called pterosaurs. The research was published in the journal PLOS ONE.
Raghavan M.,Copenhagen University |
Skoglund P.,Uppsala University |
Graf K.E.,Texas A&M University |
Metspalu M.,Evolutionary Biology Group |
And 36 more authors.
Nature | Year: 2014
The origins of the First Americans remain contentious. Although Native Americans seem to be genetically most closely related to east Asians, there is no consensus with regard to which specific Old World populations they are closest to. Here we sequence the draft genome of an approximately 24,000-year-old individual (MA-1), from Mal'ta in south-central Siberia, to an average depth of 1×. To our knowledge this is the oldest anatomically modern human genome reported to date. The MA-1 mitochondrial genome belongs to haplogroup U, which has also been found at high frequency among Upper Palaeolithic and Mesolithic European hunter-gatherers, and the Y chromosome of MA-1 is basal to modern-day western Eurasians and near the root of most Native American lineages. Similarly, we find autosomal evidence that MA-1 is basal to modern-day western Eurasians and genetically closely related to modern-day Native Americans, with no close affinity to east Asians. This suggests that populations related to contemporary western Eurasians had a more north-easterly distribution 24,000 years ago than commonly thought. Furthermore, we estimate that 14 to 38% of Native American ancestry may originate through gene flow from this ancient population. This is likely to have occurred after the divergence of Native American ancestors from east Asian ancestors, but before the diversification of Native American populations in the New World. Gene flow from the MA-1 lineage into Native American ancestors could explain why several crania from the First Americans have been reported as bearing morphological characteristics that do not resemble those of east Asians. Sequencing of another south-central Siberian, Afontova Gora-2 dating to approximately 17,000 years ago, revealed similar autosomal genetic signatures as MA-1, suggesting that the region was continuously occupied by humans throughout the Last Glacial Maximum. Our findings reveal that western Eurasian genetic signatures in modern-day Native Americans derive not only from post-Columbian admixture, as commonly thought, but also from a mixed ancestry of the First Americans. © 2014 Macmillan Publishers Limited.
Hudjashov G.,Evolutionary Biology Group
PloS one | Year: 2013
Global variation in skin pigmentation is one of the most striking examples of environmental adaptation in humans. More than two hundred loci have been identified as candidate genes in model organisms and a few tens of these have been found to be significantly associated with human skin pigmentation in genome-wide association studies. However, the evolutionary history of different pigmentation genes is rather complex: some loci have been subjected to strong positive selection, while others evolved under the relaxation of functional constraints in low UV environment. Here we report the results of a global study of the human tyrosinase gene, which is one of the key enzymes in melanin production, to assess the role of its variation in the evolution of skin pigmentation differences among human populations. We observe a higher rate of non-synonymous polymorphisms in the European sample consistent with the relaxation of selective constraints. A similar pattern was previously observed in the MC1R gene and concurs with UV radiation-driven model of skin color evolution by which mutations leading to lower melanin levels and decreased photoprotection are subject to purifying selection at low latitudes while being tolerated or even favored at higher latitudes because they facilitate UV-dependent vitamin D production. Our coalescent date estimates suggest that the non-synonymous variants, which are frequent in Europe and North Africa, are recent and have emerged after the separation of East and West Eurasian populations.
PubMed | University Utrecht, CSIR - Central Electrochemical Research Institute and Evolutionary Biology Group
Type: | Journal: Scientific reports | Year: 2016
The global distribution of J2-M172 sub-haplogroups has been associated with Neolithic demic diffusion. Two branches of J2-M172, J2a-M410 and J2b-M102 make a considerable part of Y chromosome gene pool of the Indian subcontinent. We investigated the Neolithic contribution of demic dispersal from West to Indian paternal lineages, which majorly consists of haplogroups of Late Pleistocene ancestry. To accomplish this, we have analysed 3023 Y-chromosomes from different ethnic populations, of which 355 belonged to J2-M172. Comparison of our data with worldwide data, including Y-STRs of 1157 individuals and haplogroup frequencies of 6966 individuals, suggested a complex scenario that cannot be explained by a single wave of agricultural expansion from Near East to South Asia. Contrary to the widely accepted elite dominance model, we found a substantial presence of J2a-M410 and J2b-M102 haplogroups in both caste and tribal populations of India. Unlike demic spread in Eurasia, our results advocate a unique, complex and ancient arrival of J2a-M410 and J2b-M102 haplogroups into Indian subcontinent.
News Article | December 17, 2015
The fossil of a newly discovered dinosaur shows it possessed a strange, rigid "sail" on its back that may have helped it survive ancient episodes of climate change, paleontologists suggest. Around 125 million years ago its home region in what is now modern Spain had alternating periods of wet and dry climates, and the dinosaur's sail may have helped it regulate it body temperature, they theorize. Modern elephants do something similar, the point out, using their large ears to radiate excess body heat away. Or, perhaps like a camel's hump, the bony sail on the plant-eating dino Morelladon beltrani may have been a place to store fat to keep the animals alive during times of food scarcity, they say. That could have come in especially handy if the species was a migratory one, they suggest. Although there's no direct evidence M. beltrani migrated, fossil evidence from other dinosaur types found in the region showed they lived in herds that may have periodically migrated with changes in the local environment. Large modern herbivores, such as elephants or many other species of animals, commonly migrate, the researchers point out. Morelladon beltrani was named after a quarry near the northeastern Spanish city of Morella where the fossil was unearthed in 2013, and in honor of Victor Beltrán, who assisted at the dig sites around the quarry. As an herbivore, 14 large teeth in the creature's mouth would have helped it graze on and process tough plant materials, the paleonotologists note. Fossil evidence for the animal's sail was a row of bony spines, some a foot tall, which would have extended upward from the dinosaur's back. In life the creature was around 20 feet long and would have stood about 8 feet tall at the shoulder, the researchers say in their study published in PLOS One. M. beltrani was probably related to plant-eating Iguanodons, one of the most successful dinosaur groups ever, which colonized many regions of the world, the researchers say. The finding is yet more evidence that Europe in the Early Cretaceous period was host to a large number of different iguanodontian dinosaurs, says study co-author Fernando Escaso of the Evolutionary Biology Group at the National Distance Education University in Madrid. "We knew the dinosaur fauna from Morella was similar to those of other contemporary European sites," he says. "However, this discovery shows an interesting rise of the iguanodontoid diversity in southern Europe around 125 million years ago."
News Article | December 21, 2015
The bizarre rigid "sail" on the back of a newfound species of herbivorous dinosaur may have helped the paleo-beast survive in a variety of climates, a new study finds. The dinosaur lived during the Early Cretaceous period about 125 million years ago in ancient Spain, the researchers said. During that time, some areas of Iberia had alternating wet and dry periods. Perhaps the dinosaur used its sail to regulate its body temperature, much like an elephant uses its large ears to release excess body heat, the researchers said. Or, the dinosaur could have used the sail as a place to store fat to use when resources were scarce, the scientists said. [Paleo-Art: Dinosaurs Come to Life in Stunning Illustrations] The dinosaur remains were discovered in May 2013 in a quarry near the city of Morella in northeastern Spain, said study co-author Fernando Escaso, an assistant professor for the Evolutionary Biology Group at the National Distance Education University in Madrid, Spain. Since then, Escaso and his colleagues have been excavating and examining the bones. The researchers named the new species Morelladon beltrani, for the city where it was discovered and "odon," the Greek word for "tooth." (The dinosaur's teeth are similar in shape, but not size, to those of modern iguanas, Escaso said.) The species name honors Vi?ctor Beltra?n, for his help uncovering other fossils at the Mas de la Parreta quarry, the researchers said. An analysis showed that M. beltrani measured 20 feet (6 meters) long from head to tail, and stood 8.2 feet (2.5 m) high at its shouldersThat makes the beast similar in size to its relative Mantellisaurus atherfieldensis, also known from the Early Cretaceous of ancient Europe, the researchers said. M. beltrani's most defining feature is the sail, formed by tall, boney spines that attach to the vertebrae on the animal's back. The spikes were tall, measuring up to 12 inches (31 centimeters) long, according to the fossils. If the dinosaur migrated, using the sail as a storage place for fat would have come in handy, Escaso said. There is no direct evidence that M. beltrani migrated, but fossil discoveries show that other dinosaurs from the Mas de la Parreta quarry lived in herds. Moreover, large modern herbivores such as elephants that live in herds also migrate, Escaso said. The study was published online today (Dec. 16) in the journal PLOS ONE. Copyright 2015 LiveScience, a Purch company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.