Faunal record identifies Bering isthmus conditions as constraint to end-Pleistocene migration to the New World

Abstract

Human colonization of the New World is generally believed to have entailed migrations from Siberia across the Bering isthmus. However, the limited archaeological record of these migrations means that details of the timing, cause and rate remain cryptic. Here, we have used a combination of ancient DNA, 14C dating, hydrogen and oxygen isotopes, and collagen sequencing to explore the colonization history of one of the few other large mammals to have successfully migrated into the Americas at this time: the North American elk ( Cervus elaphus canadensis ), also known as wapiti. We identify a long-term occupation of northeast Siberia, far beyond the species’s current Old World distribution. Migration into North America occurred at the end of the last glaciation, while the northeast Siberian source population became extinct only within the last 500 years. This finding is congruent with a similar proposed delay in human colonization, inferred from modern human mitochondrial DNA, and suggestions that the Bering isthmus was not traversable during parts of the Late Pleistocene. Our data imply a fundamental constraint in crossing Beringia, placing limits on the age and mode of human settlement in the Americas, and further establish the utility of ancient DNA in palaeontological investigations of species histories.

Mitochondrial genome diversity at the Bering Strait area highlights prehistoric human migrations from Siberia to northern North America

“…2 A significant environmental shift was driven by the warming, which occurred in the High Arctic~17-15 kya. 3 It appears that some Siberian groups may have reached western Alaskã 14.5 kya, whereas others were stuck in the lowlands of central Beringia (the Bering Isthmus proper) until the last flooding of the Bering Strait,~11.5 kya. 4 The northern rim of the Pacific, offering a wealth of resources, may have led coastal migrants deep into the interior from marine and estuarine habitats to riverine, lake, and marsh ecosystems all the way down the Pacific Coast of North America.…”

Genetic signature of natural selection in first Americans

“…Around 25,000 yBP, the Last Glacial Maximum (LGM) drastically reduced sea levels. In the region where we currently find the Bering Strait, this drop in sea level exposed an unglaciated land extension known as the Bering land bridge, which joined Northeast Asia and North America, forming Beringia (3)(4)(5). Most of the studies on the peopling of the Americas agree that the genetic differentiation of the current Native American populations probably occurred in this area during a standstill in Beringia (6)(7)(8)(9), where migrants from different regions in Asia had arrived about 23,000 yBP, inhabiting it for a few thousand years (5,000-8,000 y) (1).…”

Underwater faunal assemblages: radiocarbon dates and late Quaternary vertebrates from Cold Lake, Alberta and Saskatchewan, Canada

“…In Alces alces, 519 the elongate facet continues farther medially across the posterior portion of the proximal metatarsal. 520 521 DISCUSSION: Elk, like moose, are known only from the Holocene record of Alberta (e.g., Burns 1986) 522 and are probably a recent immigrant to North America (Burns 2010;Meiri et al 2013). Although the 523 specimens reported here do not clarify current interpretations of population dynamics based on historic 524 elk records (e.g., Speller et al 2014), they may present the opportunity for additional testing, assuming 525 any preserve ancient DNA.…”