Majumder Partha P, Basu Analabha
National Institute of Biomedical Genomics, Kalyani 741251, India.
Cold Spring Harb Perspect Biol. 2014 Aug 21;7(4):a008540. doi: 10.1101/cshperspect.a008540.
Recent advances in molecular and statistical genetics have enabled the reconstruction of human history by studying living humans. The ability to sequence and study DNA by calibrating the rate of accumulation of changes with evolutionary time has enabled robust inferences about how humans have evolved. These data indicate that modern humans evolved in Africa about 150,000 years ago and, consistent with paleontological evidence, migrated out of Africa. And through a series of settlements, demographic expansions, and further migrations, they populated the entire world. One of the first waves of migration from Africa was into India. Subsequent, more recent, waves of migration from other parts of the world have resulted in India being a genetic melting pot. Contemporary India has a rich tapestry of cultures and ecologies. There are about 400 tribal groups and more than 4000 groups of castes and subcastes, speaking dialects of 22 recognized languages belonging to four major language families. The contemporary social structure of Indian populations is characterized by endogamy with different degrees of porosity. The social structure, possibly coupled with large ecological heterogeneity, has resulted in considerable genetic diversity and local genetic differences within India. In this essay, we provide genetic evidence of how India may have been peopled, the nature and extent of its genetic diversity, and genetic structure among the extant populations of India.
分子遗传学和统计遗传学的最新进展使得通过研究现存人类来重建人类历史成为可能。通过校准进化时间内变化积累的速率来对DNA进行测序和研究的能力，使得人们能够对人类的进化方式做出可靠的推断。这些数据表明，现代人类大约在15万年前在非洲进化，并且与古生物学证据一致，他们迁出了非洲。通过一系列的定居、人口扩张和进一步的迁徙，他们遍布了整个世界。从非洲的第一波迁徙浪潮之一就是进入印度。随后，来自世界其他地区的更近一波的迁徙浪潮使得印度成为了一个基因熔炉。当代印度有着丰富多样的文化和生态。大约有400个部落群体以及4000多个种姓和亚种姓群体，说着属于四大语系的22种公认语言的方言。印度人群体的当代社会结构以不同程度的封闭性内婚制为特征。这种社会结构，可能再加上巨大的生态异质性，导致了印度境内相当大的遗传多样性和局部遗传差异。在本文中，我们提供了关于印度可能是如何被人类定居的遗传证据、其遗传多样性的性质和程度，以及印度现存人群之间的遗传结构。
