Temporal fluctuation in North East Baltic Sea region cattle population revealed by mitochondrial and Y-chromosomal DNA analyses.

Marianna Niemi,Eve Rannamäe,Veronica Nyström Edmark,Janne Harjula,Lembi Lõugas,Terhi Iso-Touru,Auli Bläuer,Kerstin Lidén,Antti Sajantila,Jussi-Pekka Taavitsainen,Yong-Gang Yao

doi:10.1371/journal.pone.0123821

Abstract

BackgroundAncient 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.ResultsBones 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).ConclusionsThe 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.

Highlights

Archaeological and mitochondrial DNA evidence indicate that cattle were domesticated from the auroch (Bos primigenius) [1,2,3,4,5], about 10,000 years ago in the Fertile Crescent [6]
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 PostMedieval (26) periods were investigated by sequencing 667 base pairs from the mitochondrial DNA and 155 bp of intron 19 in the Y-chromosomal UTY gene
Comparison of maternal genetic diversity in ancient cattle (45 samples) with modern cattle populations in Europe and Asia (2094 samples) revealed 30 ancient mitochondrial DNA (mtDNA) haplotypes, 24 of which were shared with modern breeds, while 6 were unique to the ancient samples

Summary

Introduction

Archaeological and mitochondrial DNA evidence indicate that cattle were domesticated from the auroch (Bos primigenius) [1,2,3,4,5], about 10,000 years ago in the Fertile Crescent [6]. Variation in the hypervariable region of the mithochondrial D-loop defines the majority of taurine cattle, as well as some mitochondrial lineages of Near Eastern aurochs and many Italian aurochs [12], to belong to the T mega-haplogroup, including the haplogroups T, T1, T2, T3, and T4 [1,5,13,14,15]. The oldest diverging branch in the mtDNA phylogeny is the very rare haplogroup R that has only been identified in local Italian cattle breeds [16]. The genetic structure of modern cattle populations is well known given the undertaking of several molecular and population genetic studies

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