Niemi Marianna, Bläuer Auli, Iso-Touru Terhi, Harjula Janne, Nyström Edmark Veronica, Rannamäe Eve, Lõugas Lembi, Sajantila Antti, Lidén Kerstin, Taavitsainen Jussi-Pekka
Biotechnology and Food Research, MTT Agrifood Research Finland, Jokioinen, Finland; University of Helsinki, Department of Forensic Medicine, Helsinki, Finland.
Biotechnology and Food Research, MTT Agrifood Research Finland, Jokioinen, Finland; Department of Archaeology, University of Turku, Turku, Finland.
PLoS One. 2015 May 20;10(5):e0123821. doi: 10.1371/journal.pone.0123821. eCollection 2015.
Ancient DNA analysis offers a way to detect changes in populations over time. To date, most studies of ancient cattle have focused on their domestication in prehistory, while only a limited number of studies have analysed later periods. Conversely, the genetic structure of modern cattle populations is well known given the undertaking of several molecular and population genetic studies.
Bones and teeth from ancient cattle populations from the North-East Baltic Sea region dated to the Prehistoric (Late Bronze and Iron Age, 5 samples), Medieval (14), and Post-Medieval (26) periods were investigated by sequencing 667 base pairs (bp) from the mitochondrial DNA (mtDNA) and 155 bp of intron 19 in the Y-chromosomal UTY gene. Comparison of maternal (mtDNA haplotypes) genetic diversity in ancient cattle (45 samples) with modern cattle populations in Europe and Asia (2094 samples) revealed 30 ancient mtDNA haplotypes, 24 of which were shared with modern breeds, while 6 were unique to the ancient samples. Of seven Y-chromosomal sequences determined from ancient samples, six were Y2 and one Y1 haplotype. Combined data including Swedish samples from the same periods (64 samples) was compared with the occurrence of Y-chromosomal haplotypes in modern cattle (1614 samples).
The diversity of haplogroups was highest in the Prehistoric samples, where many haplotypes were unique. The Medieval and Post-Medieval samples also show a high diversity with new haplotypes. Some of these haplotypes have become frequent in modern breeds in the Nordic Countries and North-Western Russia while other haplotypes have remained in only a few local breeds or seem to have been lost. A temporal shift in Y-chromosomal haplotypes from Y2 to Y1 was detected that corresponds with the appearance of new mtDNA haplotypes in the Medieval and Post-Medieval period. This suggests a replacement of the Prehistoric mtDNA and Y chromosomal haplotypes by new types of cattle.
古代DNA分析提供了一种检测种群随时间变化的方法。迄今为止，大多数关于古代牛的研究都集中在它们史前时期的驯化，而只有少数研究分析了后期阶段。相反，鉴于进行了多项分子和群体遗传学研究，现代牛种群的遗传结构是众所周知的。
对来自波罗的海东北部地区史前时期（青铜时代晚期和铁器时代，5个样本）、中世纪时期（14个样本）和后中世纪时期（26个样本）的古代牛种群的骨骼和牙齿进行了研究，对线粒体DNA（mtDNA）的667个碱基对（bp）和Y染色体UTY基因内含子19的155bp进行了测序。将古代牛（45个样本）的母系（mtDNA单倍型）遗传多样性与欧洲和亚洲的现代牛种群（2094个样本）进行比较，发现了30种古代mtDNA单倍型，其中24种与现代品种共有，而6种是古代样本所特有的。从古代样本中确定的7个Y染色体序列中，6个是Y2单倍型，1个是Y1单倍型。将包括同一时期瑞典样本（64个样本）的综合数据与现代牛（1614个样本）中Y染色体单倍型的出现情况进行了比较。
单倍群的多样性在史前样本中最高，其中许多单倍型是独特的。中世纪和后中世纪样本也显示出高多样性，有新的单倍型。其中一些单倍型在北欧国家和俄罗斯西北部的现代品种中变得常见，而其他单倍型仅保留在少数地方品种中或似乎已经消失。检测到Y染色体单倍型从Y2到Y1的时间变化，这与中世纪和后中世纪时期新的mtDNA单倍型的出现相对应。这表明史前的mtDNA和Y染色体单倍型被新型牛所取代。
