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Loog, L.

Publications and source records attributed to Loog, L..

2 recordsLinked to original sources

Modern wolves trace their origin to a late Pleistocene expansion from Beringia

Grey wolves (Canis lupus) are one of the few large terrestrial carnivores that maintained a wide geographic distribution across the Northern Hemisphere throughout the Pleistocene and Holocene. Recent genetic studies have suggested that, despite this continuous presence, major demographic changes occurred in wolf populations between the late Pleistocene and early Holocene, and that extant wolves trace their ancestry to a single late Pleistocene population. Both the geographic origin of this ancestral population and how it became widespread remain a mystery. Here we analyzed a large dataset of novel modern and ancient mitochondrial wolf genomes, spanning the last 50,000 years, using a spatially and temporally explicit modeling framework to show that contemporary wolf populations across the globe trace their ancestry to an expansion from Beringia at the end of the Last Glacial Maximum - a process most likely driven by the significant ecological changes that occurred across the Northern Hemisphere during this period. This study provides direct ancient genetic evidence that long-range migration has played an important role in the population history of a large carnivore and provides an insight into how wolves survived the wave of megafaunal extinctions at the end of the last glaciation. Moreover, because late Pleistocene grey wolves were the likely source from which all modern dogs trace their origins, the demographic history described in this study has fundamental implications for understanding the geographical origin of the dog.

evolutionary biology

Predicting the viability of archaic human hybrids using a mitochondrial proxy

Ancient DNA evidence has confirmed hybridization between humans and Neanderthals and revealed a complex pattern of admixture between hominin lineages. Many segments of the modern human genome are devoid of Neanderthal ancestry, however, and this non-random distribution has raised questions regarding the frequency and success of hybridisation between ancient human lineages. Here, we examine the hypothesis that hominin hybrid offspring suffered a reduction in fertility by comparing patterns of sequence divergence of mitochondrial and nuclear DNA from numerous hybridising pairs of mammals. Our results reveal a threshold separating species pairs whose divergence values fall within two categories: those whose hybrid offspring can successfully reproduce without backcrossing with their parent species, and those whose hybrid offspring cannot. Using this framework, we predict that the potential hybrid offspring of Neanderthals, Denisovans, the ancient individuals from the Sima de los Huesos and anatomically modern humans would not have suffered a reduction in fertility.

evolutionary biology