A history of cattle breeding by the book?

Ancient DNA technology may make it possible to test some very interesting hypotheses about recent evolutionary change in human populations.

Meanwhile, several people are reporting the potential of DNA from museum specimens for testing hypotheses about ancient or extinct populations. Today’s news includes a story introducing the term “museomics” – otherwise known as the metagenomics of museum specimens, including the DNA of taxidermed specimens and their pathogens and commensal bacterial populations:

[Webb] Miller and his team used state-of-the-art DNA sequencing technology to analyze the hair of two preserved specimens: a female thylacine that died at the London Zoo in 1893, and a male brought to the National Zoo in 1902 that died three years later.
Although the two thylacines were continents apart, their mitochondrial DNA a portion of the genome passed on via the maternal line was nearly identical, illustrating the species' ultra-low genetic diversity around the turn of the 20th century.

Brandom Keim of Wired blogs that medieval parchment preserves enough DNA for analysis:

Initial tests showed that the animal skin pages contained enough intact DNA to make analysis worthwhile. So [Tim] Stinson and his brother Mike Stinson, a biologist at Southside Virginia Community College, skin samples taken from five pages of a 15th century French prayer book. Preserved mitochondrial DNA revealed that the pages came from two closely related calves.
Those results, said Stinson, are a proof of principle that it's possible to create a DNA database from manuscripts of known age and origin. Monastic paperwork tended to be dated, so DNA from those works could be cross-indexed with that of literary works from tomes of unknown provenance, producing a taxonomy of manuscript manufacture.

Sourcing manuscripts is pretty exciting to historians, no doubt, who must otherwise rely on indicators such as handwriting style and dialect.

But the results may be equally useful for understanding the processes of animal breeding in medieval Europe. Today’s domesticated breeds are a remnant of a much larger diversity of local breeds that once existed. People bred animals both locally by selection and across large regions by introducing favored animals from long distances. Sometimes they favored diversity – and considering the revival of interest in legacy breeds like Highland cattle.

As an example, today’s European swine include a blend of genes from ancient European domesticates, and hogs introduced from China during the 18th and 19th centuries (Giuffra et al. 2000). That introgression probably caused some substantial improvements in the hog population, but has helped to reduce genetic variation and move the population from its medieval structure to a more homogenized gene pool.

Gregory Cochran and I gave a short description of the history of cattle domestication and ongoing gene flow in our 2006 paper about introgression (Hawks and Cochran 2006). With four original cattle species in different parts of Eurasia, and the possibility of continued gene flow among imported breeds as well as the original progenitor species of European cattle, the aurochs (still known in early medieval times), the population history of European breeds may harbor a lot of complexity during the last 1000 years. Finding the medieval distribution of today’s genes – even if the only result is a mitochondrial DNA distribution – might help us understand the distribution in which favored traits originated and were selected.

References:

Giuffra E, Kijas JMH, Amarger V, Carlborg Ö, Jeon J-T, Andersson L. 2000. The origin of the domestic pig: Independent domestication and subsequent introgression. Genetics 154:1785-1791.

Hawks J, Cochran G. 2006. Dynamics of adaptive introgression from archaic to modern humans. PaleoAnthropology 2006:101-115.