Spotted phenotypes in horses lost attractiveness in the Middle Ages

Horses have been valued for their diversity of coat colour since prehistoric times; this is especially the case since their domestication in the Caspian steppe in ~3,500 BC. Although we can assume that human preferences were not constant, we have only anecdotal information about how domestic horses were influenced by humans. Our results from genotype analyses show a significant increase in spotted coats in early domestic horses (Copper Age to Iron Age). In contrast, medieval horses carried significantly fewer alleles for these phenotypes, whereas solid phenotypes (i.e., chestnut) became dominant. This shift may have been supported because of (i) pleiotropic disadvantages, (ii) a reduced need to separate domestic horses from their wild counterparts, (iii) a lower religious prestige, or (iv) novel developments in weaponry. These scenarios may have acted alone or in combination. However, the dominance of chestnut is a remarkable feature of the medieval horse population.Peer Reviewe

Ritual responses to catastrophic volcanism in Viking Age Iceland: Reconsidering Surtshellir Cave through Bayesian analyses of AMS dates, tephrochronology, and texts.

Surtshellir, a 1600-m-long lava cave in the interior of Iceland, contains a unique Viking Age archaeological site located nearly 300 m from its entrance and more than 10 m below the surface of the Hallmundarhraun lava field. Since the 1750s, the site has been interpreted as an outlaw shelter, yet in the 12th-13th centuries it was associated with actions directed towards an elemental being – Surtr – for whom the site was named and who, according to medieval Icelandic accounts of Viking Age mythology, was present at the world's creation and would destroy it after the battle of Ragnarök. Archaeological fieldwork inside Surtshellir in 2001, 2012, and 2013 produced 20 new AMS dates that, combined with three earlier radiocarbon and tephrochronological dates, provide the basis for Bayesian analyses which suggest (1) that the cave formed in the first major volcanic eruption directly witnessed by northern Europeans since the Late Pleistocene; (2) that this took place shortly after the Norse colonization of Iceland began; (3) that people entered the cave soon afterwards; (4) that for 80–120 years they deposited the fragmented bones of slaughtered domestic animals in piles stretching 120 m through the cave's “dark zone”, burning others at high temperatures in a dry-stone structure built deep inside a raised side passage; and (5) that these activities ended shortly after Iceland's conversion to Christianity. Surtshellir provides important new insights into Viking Age ritual practice, Iceland's settlement and conversion, and the cultural responses of Iceland's newly arrived settlers to the existential challenges posed by previously unimagined catastrophic volcanism

The preservation of ancient DNA in archaeological fish bone

The field of ancient DNA is dominated by studies focusing on terrestrial vertebrates. This taxonomic bias limits our understanding of endogenous DNA preservation for species with different bone physiology, such as teleost fish. Teleost bone is typically brittle, porous, lightweight, and is characterized by a lack of bone remodeling during growth. All of these factors potentially affect DNA preservation. Using high-throughput shotgun sequencing, we here investigate the preservation of DNA in a range of different bone elements from over 200 archaeological Atlantic cod (Gadus morhua) specimens from 38 sites in northern Europe, dating up to 8000 years before present. We observe that the majority of archaeological sites (79%) yield endogenous DNA, with 40% of sites providing samples containing high levels (>20%). Library preparation success and levels of endogenous DNA depend mainly on excavation site and pre-extraction laboratory treatment. The use of pre-extraction treatments lowers the rate of libraries that can be sequenced, although — if successful — the fraction of endogenous DNA can be improved by several orders of magnitude. This trade-off between library preparation success and levels of endogenous DNA allows for alternative extraction strategies depending on the requirements of down-stream analyses and research questions. Finally, we do not find particular bone elements to yield higher levels of endogenous DNA, as is the case for denser bones in mammals. Our results highlight the potential of archaeological fish bone as a source for ancient DNA and suggest a possible role of bone remodeling in the preservation of endogenous DNA