Genetic Evolution in South Indian Caste Populations

长期以来，人类学家一直对生物学和文化之间的关系感兴趣。 印度种姓制度在印度人口中建立了首选的交配做法，是社会进程对人类生物学影响的一个很好的例子。 许多研究人员研究了种姓制度对遗传变异的影响。 然而，由于几个原因，从这一系列工作中得出的结论仍然不能令人信服。 首先，许多多态性分析是DNA变异的间接测量，仅从少数位点取样，并且不是选择性中性的。 其次，许多研究没有估计显著性水平或置信区间，使研究结果令人怀疑。 最后，没有与大陆人群进行系统的比较（即，非洲人、亚洲人和欧洲人）使用大量统一的DNA多态性。 迄今为止，还没有人利用分子生物学的最新进展来解决印度人类进化中长期存在的重要问题。 拟议的研究将严格调查南印度种姓人口的遗传进化（1）制定和测试种姓细分对遗传变异的影响的假设;（2）使用各种线粒体和核DNA多态性;（3）与大陆人口进行直接比较。 该研究将分析线粒体DNA、Y染色体DNA和常染色体DNA多态性，这些多态性具有不同的突变率，这些突变来自代表跨种姓等级和2个部落人群的4个种姓中的个体的样本。 将与我们现有的种姓和大陆人口数据进行比较。

Anthropologists have long been interested in the relationship between biology and culture. The Hindu caste system, which established preferred mating practices among the populations of India, is a good example of the impact of social processes on human biology. Numerous investigators have studied the effect of the caste system on genetic variation. Yet the generalizations from this body of work remain unconvincing for several reasons. First, many of the polymorphisms assayed are indirect measurements of DNA variation, are sampled from only a few loci, and are not selectively neutral. Second, many studies do not estimate significance levels or confidence intervals, leaving the findings suspect. Finally, no systematic comparisons have been made with continental populations (i.e., Africans, Asians, and Europeans) using a large, uniform set of DNA polymorphisms. To date, no one has taken advantage of the recent advances in molecular biology to address unresolved questions of long-standing importance to human evolution in India. The proposed research will critically investigate the genetic evolution of South Indian caste populations by (1) formulating and testing hypotheses of the effect of caste subdivision on genetic variation; (2) using a variety of mitochondrial and nuclear DNA polymorphisms; and (3) making direct comparisons to continental populations. The study will analyze mitochondrial DNA, Y-chromosomal DNA, and autosomal DNA polymorphisms with differing rates of mutation from a sample representing individuals in 4 castes spanning the caste hierarchy and 2 tribal populations. Comparisons will be made to our existing data from caste and continental populations.