CIBIO/InBIO: Research Center in Biodiversity and Genetic Resources, 4485-661, Vairão, Portugal.
Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, 4169-007, Porto, Portugal.
Eur J Hum Genet. 2019 Mar;27(3):475-483. doi: 10.1038/s41431-018-0304-2. Epub 2018 Nov 22.
Southwestern Angola is a region characterized by contact between indigenous foragers and incoming food-producers, involving genetic and cultural exchanges between peoples speaking Kx'a, Khoe-Kwadi, and Bantu languages. Although present-day Bantu speakers share a patrilocal residence pattern and matrilineal principle of clan and group membership, a highly stratified social setting divides dominant pastoralists from marginalized groups that subsist on alternative strategies and have previously been thought to have pre-Bantu origins. Here, we compare new high-resolution sequence data from 2.3 Mb of the male-specific region of the Y chromosome (MSY) from 170 individuals with previously reported mitochondrial DNA (mtDNA) genomes, to investigate the population history of seven representative southwestern Angolan groups (Himba, Kuvale, Kwisi, Kwepe, Twa, Tjimba, !Xun), and to study the causes and consequences of sex-biased processes in their genetic variation. We found no clear link between the formerly Kwadi-speaking Kwepe and pre-Bantu eastern African migrants, and no pre-Bantu MSY lineages among Bantu-speaking groups, except for small amounts of "Khoisan" introgression. We therefore propose that irrespective of their subsistence strategies, all Bantu-speaking groups of the area share a male Bantu origin. Additionally, we show that in Bantu-speaking groups, the levels of among-group and between-group variation are higher for mtDNA than for MSY. These results, together with our previous demonstration that the matriclanic systems of southwestern Angolan Bantu groups are genealogically consistent, suggest that matrilineality strongly enhances both female population sizes and interpopulation mtDNA variation.
西南安哥拉地区的特点是原住民觅食者与外来食物生产者之间的接触，这涉及到讲 Kx'a、Khoe-Kwadi 和班图语等语言的民族之间的基因和文化交流。尽管当今的班图语使用者具有父系居住模式和母系氏族和群体成员的原则，但高度分层的社会环境将占主导地位的牧民与依赖替代策略生存的边缘化群体区分开来，而这些边缘化群体以前被认为具有前班图语起源。在这里，我们比较了来自 170 个人的 Y 染色体（MSY）男性特异性区域的 2.3 Mb 的新的高分辨率序列数据，以及先前报道的线粒体 DNA（mtDNA）基因组，以调查七个具有代表性的西南安哥拉群体（辛巴、夸韦尔、奎西、克威佩、图瓦、津巴、!Xun）的人口历史，并研究其遗传变异中性别偏向过程的原因和后果。我们没有发现以前讲 Kwadi 语的克威佩人与来自东非的前班图语移民之间有明显的联系，也没有在讲班图语的群体中发现前班图语的 MSY 谱系，除了少量的“科伊桑”渗入。因此，我们提出，无论其生存策略如何，该地区所有讲班图语的群体都具有男性班图语起源。此外，我们表明，在讲班图语的群体中，mtDNA 的群体内和群体间变异水平高于 MSY。这些结果，加上我们之前的研究表明，西南安哥拉班图语群体的母系氏族系统在系谱上是一致的，表明母系制强烈增强了女性群体规模和群体间 mtDNA 变异。
