Mitochondrial Ewe - application of ancient DNA typing to the study of domestic sheep (Ovis aries) in mediaeval Norway

Around 11000 years ago the first domesticated mammals emerged in the Fertile Crescent. Over time, these animals spread to fertile regions both to the east and west of their domestic centre of origin. By 6000 BP, animal husbandry had reached Northern Europe, and it had become established in Norway by circa 4100 BP. Domestic sheep (Ovis aries) was probably among the first domestic species to be introduced to Norway and by the Middle Ages (476- 1453 AD) animal husbandry and sheep herding was well established here. Not much is known about the composition of domestic sheep in mediaeval Norway, but it has been suggested that new breeds were introduced from other countries as this was a time of increasing trade. Four different mitochondrial DNA (mtDNA) haplogroups, known as A, B, C and D, have been observed in domestic sheep, of which mtDNA haplogroup A and B are found in Europe. In this study I analysed genetic data obtained from sheep bones excavated from archaeological sites (Oslo, Bergen and Trondheim) in Norway dated to the Middle Ages (476- 1453 AD). I also included a bone sample dated to the Viking Age (800-1066 AD) to see if any genetic variation could be obtained from an older sample. I implemented methods for extracting ancient mtDNA from bones, and aimed to produce reliable extracts that could be authenticated as mediaeval sheep DNA. Authentic mtDNA sequences of mediaeval domestic sheep could provide information that would help answer questions regarding the trading history and composition of breeds at different geographical regions in mediaeval Norway. Sheep extracts were amplified with sheep specific primers and cytochrome b primers simultaneously. Negative and positive controls, as well as samples of different species were included in the amplifications. PCR amplifications visualised on electrophoresis agarose gels could exclude human and cross-contamination of sheep by the nature of the controls. This suggested that the genetic data were authentic. Of 70 domestic sheep samples, 16 were successfully sequenced, including one from the Viking Age. Two mtDNA haplogroups were observed: A and B. One specimen from Trondheim was allocated to haplogroup A, whereas the remaining samples were haplogroup B. The 16 sequences used in the phylogenetic analyses were short (88 bp), and thus not informative enough to settle questions regarding the trade and composition of breeds in mediaeval Norway. However, it could be concluded that the sheep sequences were authentic, and that two mtDNA sheep lineages were present in Norway in the Middle Ages