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- Götherström, Anders, et al.
(författare)
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Cattle domestication in the Near East was followed by hybridization with aurochs bulls in Europe.
- 2005
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Ingår i: Proc Biol Sci. - 0962-8452. ; 272:1579, s. 2345-50
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Tidskriftsartikel (refereegranskat)abstract
- Domesticated cattle were one of the cornerstones of European Neolithisation and are thought to have been introduced to Europe from areas of aurochs domestication in the Near East. This is consistent with mitochondrial DNA (mtDNA) data, where a clear separation exists between modern European cattle and ancient specimens of British aurochsen. However, we show that Y chromosome haplotypes of north European cattle breeds are more similar to haplotypes from ancient specimens of European aurochsen, than to contemporary cattle breeds from southern Europe and the Near East. There is a sharp north-south gradient across Europe among modern cattle breeds in the frequencies of two distinct Y chromosome haplotypes; the northern haplotype is found in 20 out of 21 European aurochsen or early domestic cattle dated 9500-1000 BC. This indicates that local hybridization with male aurochsen has left a paternal imprint on the genetic composition of modern central and north European breeds. Surreptitious mating between aurochs bulls and domestic cows may have been hard to avoid, or may have occurred intentionally to improve the breeding stock. Rather than originating from a few geographical areas only, as indicated by mtDNA, our data suggest that the origin of domestic cattle may be far more complex than previously thought.
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| 3. |
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| 4. |
- Hellborg, Linda, 1973-
(författare)
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Evolutionary Studies of the Mammalian Y Chromosome
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Sex chromosomes are useful in elucidating the evolutionary factors affecting diversity and divergence. In particular, Y chromosome analyses may complement studies using mitochondrial DNA for inferring sex-specific population genetic processes.Y chromosome studies have been scarce due to limited access to genetic markers and the dynamic evolution of Y. Conserved Y-specific primers that could amplify a diverse set of mammalian species were developed from comparison of gametologous X and Y sequences. Y-specific sequence, generally more than one kb, was amplified for all 20 species examined.Intraspecific diversity on mammalian Y was found to be reduced even when male-biased mutation rate and effective population size were corrected for. A number of factors can cause this low variation on Y of which selection on a haploid chromosome seems most important.The field vole (Microtus agrestis), a common and well-studied small mammal in Eurasia, was examined for X and Y variability. Earlier studies on mtDNA had shown that the field vole is separated in two distinct lineages in Europe. The X and Y chromosome sequences confirmed the deep split and suggested that the two lineages of field vole should be reclassified as two separate species.Two distinct Y chromosome haplogroups were found in modern European cattle, distributed among breeds according to a north-south gradient. Ancient DNA analysis of European aurochsen showed the northern haplogroup to be the most common, possibly indicating local hybridization between domestic cows and wild aurochs bulls in Europe.
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| 6. |
- Lindgren, Gabriella, et al.
(författare)
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Limited number of patrilines in horse domestication.
- 2004
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 36:4
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Tidskriftsartikel (refereegranskat)abstract
- Genetic studies using mitochondrial DNA (mtDNA) have identified extensive matrilinear diversity among domestic horses. Here, we show that this high degree of polymorphism is not matched by a corresponding patrilinear diversity of the male-specific Y chromosome. In fact, a screening for single-nucleotide polymorphisms (SNPs) in 14.3 kb of noncoding Y chromosome sequence among 52 male horses of 15 different breeds did not identify a single segregation site. These observations are consistent with a strong sex-bias in the domestication process, with few stallions contributing genetically to the domestic horse.
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