Biotechnology and Food Research, MTT Agrifood Research Finland, Jokioinen, Finland.
Genet Sel Evol. 2013 Jan 22;45(1):2. doi: 10.1186/1297-9686-45-2.
Several molecular and population genetic studies have focused on the native sheep breeds of Finland. In this work, we investigated their ancestral sheep populations from Iron Age, Medieval and Post-Medieval periods by sequencing a partial mitochondrial DNA D-loop and the 5'-promoter region of the SRY gene. We compared the maternal (mitochondrial DNA haplotypes) and paternal (SNP oY1) genetic diversity of ancient sheep in Finland with modern domestic sheep populations in Europe and Asia to study temporal changes in genetic variation and affinities between ancient and modern populations.
A 523-bp mitochondrial DNA sequence was successfully amplified for 26 of 36 sheep ancient samples i.e. five, seven and 14 samples representative of Iron Age, Medieval and Post-Medieval sheep, respectively. Genetic diversity was analyzed within the cohorts. This ancient dataset was compared with present-day data consisting of 94 animals from 10 contemporary European breeds and with GenBank DNA sequence data to carry out a haplotype sharing analysis. Among the 18 ancient mitochondrial DNA haplotypes identified, 14 were present in the modern breeds. Ancient haplotypes were assigned to the highly divergent ovine haplogroups A and B, haplogroup B being the major lineage within the cohorts. Only two haplotypes were detected in the Iron Age samples, while the genetic diversity of the Medieval and Post-Medieval cohorts was higher. For three of the ancient DNA samples, Y-chromosome SRY gene sequences were amplified indicating that they originated from rams. The SRY gene of these three ancient ram samples contained SNP G-oY1, which is frequent in modern north-European sheep breeds.
Our study did not reveal any sign of major population replacement of native sheep in Finland since the Iron Age. Variations in the availability of archaeological remains may explain differences in genetic diversity estimates and patterns within the cohorts rather than demographic events that occurred in the past. Our ancient DNA results fit well with the genetic context of domestic sheep as determined by analyses of modern north-European sheep breeds.
已有多项分子和群体遗传学研究集中于芬兰的本地绵羊品种。在这项工作中，我们通过对部分线粒体 DNA D-环和 SRY 基因 5'-启动子区域进行测序，研究了来自铁器时代、中世纪和后中世纪时期的祖先绵羊群体。我们比较了芬兰古代绵羊的母系（线粒体 DNA 单倍型）和父系（SNP oY1）遗传多样性与欧洲和亚洲现代家绵羊群体，以研究遗传变异和古代与现代群体之间的亲缘关系随时间的变化。
成功扩增了 36 个绵羊古代样本中的 26 个样本的 523bp 线粒体 DNA 序列，分别代表铁器时代、中世纪和后中世纪的 5、7 和 14 个样本。在队列内分析了遗传多样性。将这个古代数据集与包括 10 个现代欧洲品种的 94 只动物的当代数据和 GenBank DNA 序列数据进行比较，以进行单倍型共享分析。在鉴定的 18 个古代线粒体 DNA 单倍型中，有 14 个存在于现代品种中。古代单倍型被分配到高度分化的绵羊单倍群 A 和 B，B 单倍群是队列中的主要谱系。在铁器时代的样本中仅检测到两个单倍型，而中世纪和后中世纪的遗传多样性更高。对三个古代 DNA 样本进行了扩增 Y 染色体 SRY 基因序列，表明它们来自公羊。这三个古代公羊样本的 SRY 基因含有 SNP G-oY1，这在现代北欧绵羊品种中很常见。
我们的研究没有发现自铁器时代以来芬兰本地绵羊种群发生重大更替的迹象。考古遗存的可利用性的变化可能解释了队列内遗传多样性估计值和模式的差异，而不是过去发生的人口事件。我们的古代 DNA 结果与通过分析北欧现代绵羊品种确定的家绵羊的遗传背景非常吻合。
