Evolutionary history and palaeoecology of brown bear in North-East Siberia re-examined using ancient DNA and stable isotopes from skeletal remains

Abstract

Over 60% of the modern distribution range of brown bears falls within Russia, yet palaeoecological data from the region remain scarce. Complete modern Russian brown bear mitogenomes are abundant in the published literature, yet examples of their ancient counterparts are absent. Similarly, there is only limited stable isotopic data of prehistoric brown bears from the region. We used ancient DNA and stable carbon (δ13C) and nitrogen (δ15N) isotopes retrieved from five Pleistocene Yakutian brown bears (one Middle Pleistocene and four Late Pleistocene), to elucidate the evolutionary history and palaeoecology of the species in the region. We were able to reconstruct the complete mitogenome of one of the Late Pleistocene specimens, but we were unable to assign it to any of the previously published brown bear mitogenome clades. A subsequent analysis of published mtDNA control region sequences, which included sequences of extinct clades from other geographic regions, assigned the ancient Yakutian bear to the extinct clade 3c; a clade previously identified from Late Quaternary specimens from Eastern Beringia and Northern Spain. Our analyses of stable isotopes showed relatively high δ15N values in the Pleistocene Yakutian brown bears, suggesting a more carnivorous diet than contemporary brown bears from Eastern Beringia.

Ancient DNA reveals multiple origins and migration waves of extinct Japanese brown bear lineages

“…Our results also establish that the stable isotope compositions ( δ 13 C and δ 15 N) of the Honshu brown bear were very similar to those of the extinct North American short-faced bear from the late Pleistocene in terms of the high proportion of δ 15 N. Large carnivores that feed on large herbivorous mammals tend to have relatively high δ 15 N values, as this value tends to be higher for larger mammals in the higher trophic positions (e.g. Rey-Iglesia et al [37]). This result suggests that the Honshu brown bears of the late Pleistocene glacial period were highly carnivorous and highly dependent on large herbivorous mammals, suggesting that they occupied an important trophic position in the middle and late Pleistocene ecosystem.…”

“…The stable isotope compositions ( δ 13 C and δ 15 N) of JBB-32 K and JBB-19 K were measured to be −17.45% and 8.68% and −17.58% and 10.11%, respectively (electronic supplementary material, figure S3). These isotopic values differed from those of current Eurasian and North American brown bears (omnivorous mammals that eat medium- to large-sized mammals and plant material including fruits) yet were very similar to those of the extinct North American short-faced bear ( Arctodus simus ) that has been considered to be more carnivorous, based on the relatively high concentration of δ 15 N [37,45], suggesting that the Honshu brown bears were also highly carnivorous.…”

“…The proportion of endogenous mtDNA (i.e. of all DNA extracted) in these samples was quite low (5.5 × 10 −7 % for JBB-19 K, 1.1 × 10 −3 % for JBB-32 K), while it typically ranges from 6 × 10 −4 % to 1 × 10 −2 % for Pleistocene fossils depending on the degree of sample preservation [37]. The numbers of endogenous reads depend on the preserved portion and the condition of specimen regardless of geological ages.…”

“…The 14 C dates converted to calendar ages were used for the tip-dating analysis. Because the Siberian Pleistocene individual (MH255807, Rey-Iglesia et al [37]) and French Pleistocene individual (EU497665, Bon et al [38]) lack accurate 14 C dating information, the dates of their tip nodes were estimated by Bayesian inference under a wide range of the uniform prior distributions (50 000 ± 50 000 BP). Because every tip date should have prior distributions in this setting of analysis, we arbitrarily provided the uniform prior distributions of 0 ± 10 BP for modern samples, and 14 C dating ± 100 BP for ancient samples reported by previous works.…”

Late Pleistocene palaeoecology and phylogeography of woolly rhinoceroses

“…Stable isotope (δ 13 C and δ 15 N) analyses of bone and tooth collagen have provided important insights into the diet and palaeoecology of Late Pleistocene megafauna, including brown bear (Ursus arctos), cave bear, cave lion, giant rhinoceros (Elasmotherium sibiricum), musk ox, saiga (Saiga tatarica), and woolly mammoth (Szpak et al 2010;Bocherens et al 2011;Raghavan et al 2014;Krajcarz et al 2016;Jürgensen et al 2017;Arppe et al 2019;Kosintsev et al 2019;Rey-Iglesia et al 2019). δ 13 C and δ 15 N have also been used to investigate the paleoecology and paleodiet of the woolly rhinoceros (Bocherens et al 1995(Bocherens et al , 1996(Bocherens et al , 1997(Bocherens et al , 2005(Bocherens et al , 2011Higham et al 2006;Jacobi et al , 2007Jacobi et al , 2009Kirillova et al 2015b;Yates et al 2017;Stefaniak et al 2020).…”