Collabortive Research: Genetic Variation Among Linguistically Diverse Tanzanian Populations: Implications for East African History and Modern Human Origins

人类线粒体、常染色体和性染色体在撒哈拉以南非洲地区表现出相对较高的遗传多样性水平，反映了该地区人口历史、迁移和细分的复杂模式，并可能是现代人类的起源。 目前的挑战是更好地描述撒哈拉以南非洲的遗传多样性，并重建该区域复杂的人口历史。 特别是东非，被认为是过去10万年内人类迁出非洲的可能来源。 然而，这一地区在遗传变异研究中仍然高度采样不足和代表性不足。 坦桑尼亚位于非洲的一个地区，在语言、文化、社会学和遗传学上都很复杂。 非洲所有四个超语系的语言使用者都彼此邻近。此外，这些人口还采用各种谋生方法。 虽然他们一直是许多人种学，语言学和考古学研究的重点，坦桑尼亚人口在遗传水平上的研究很少。 Hadzabe和Sandawe是两个目前（或最近已经）以狩猎采集为主的生活方式的人群，是语言孤立的语言，其语言包含点击辅音，并且一直是分类的挑战。 关于他们彼此之间的关系，以及与说不同语言和实行不同生存方式的相邻民族的关系，或者与南部非洲说科伊桑语的民族的关系，这些民族也说包含点击辅音的语言，并被假设起源于东非。该研究项目的具体目标是描述Hadzabe，Sandawe和邻近人群的遗传变异;重建这些东非人群彼此之间以及与南部非洲科伊桑语人群的关系;并测试有关东非现代人类可能起源的假设。 这一拟议项目分为三个相互重叠的阶段。 第一阶段包括从坦桑尼亚中部的Hadzabe、Sandawe和邻近人群收集血液和/或口腔细胞。 第二阶段包括对第一阶段收集的样本进行DNA分离和分子分型。 将对样本进行常染色体、X染色体和Y染色体上标记物的基因分型，并对mtDNA进行独立分析和单倍型分析。 第三阶段包括探索性数据分析和假设检验，给出了第二阶段产生的数据。 收集的数据将在现有的更广泛的非洲和全球数据集的范围内进行分析，预计将有助于对撒哈拉以南非洲的遗传多样性的一般了解，并有助于了解东非人口之间的古代和历史关系。 此外，由于东非可能是迁出非洲的人口来源地，这些数据将为非洲现代人类的起源和进化提供重要的新见解，并将使测试有关现代人类全球传播的广泛假设成为可能。非洲。

Human mitochondrial, autosomal, and sex chromosomes exhibit relatively high levels of genetic diversity within sub-Saharan Africa, reflecting complex patterns of population history, migration, and subdivision and possibly the origin of modern humans within this region. The current challenge is to better characterize the genetic diversity within sub-Saharan Africa and to reconstruct the complex demographic history of the region. East Africa, in particular, is thought to be a likely source of a human migration out of Africa within the last 100,000 years. This region, however, remains highly under-sampled and under-represented in studies of genetic variation. Tanzania occupies a region of Africa which is linguistically, culturally, sociologically, and genetically complex. Populations speaking languages representing all four of the linguistic super-families present in Africa are located in close proximity to one another. In addition, these populations practice a variety of subsistence methods. Although they have been the focus of many ethnographic, linguistic, and archaeological studies, Tanzanian populations have been studied very little at the genetic level. The Hadzabe and Sandawe, two populations that currently practice (or in the recent past have practiced) a predominantly hunter-gatherer lifestyle, are linguistic isolates whose languages contain click consonants and have been a challenge to classify. Little is known about their relationship to one another, to neighboring peoples who speak distinct languages and practice different subsistence methods, or to southern African Khoisan-speaking peoples who also speak languages containing click consonants and are hypothesized to have originated in East Africa. The specific goals of this research project are to characterize genetic variation in the Hadzabe, Sandawe, and neighboring populations; to reconstruct the relationship of these East African populations to one another and to southern African Khoisan-speaking populations; and to test hypotheses regarding the possible origin of modern humans in East Africa. This proposed project is divided into three overlapping phases. Phase I includes the collection of blood and/or buccal cells from the Hadzabe, Sandawe and neighboring populations in central Tanzania. Phase II consists of DNA isolation and molecular typing of the samples collected in Phase I. Samples will be genotyped for markers on autosomes, X- and Y-chromosomes, and mtDNA analyzed both independently and as haplotypes. Phase III includes exploratory data analysis and hypothesis testing given the data generated in phase II. The data collected will be analyzed within the context of a broader African and global data set that currently exists and is expected to contribute both to the general knowledge of genetic diversity within sub-Saharan Africa and to the understanding of ancient and historical relationships among East African populations. In addition, because East Africa is the likely source of populations migrating out of Africa, these data will provide important new insights into the origin and evolution of modern humans in Africa and will make possible the testing of a wide range of hypotheses concerning the global spread of modern humans out of Africa.