A 14,000-year-old genome sheds light on the evolution and extinction of a Pleistocene vulture
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Loading... - Andrea Ross
- 19 Sep 2022
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Abstract
The New World Vulture [Coragyps] occidentalis (L. Miller, 1909) is one of many species that were extinct by the end of the Pleistocene. To understand its evolutionary history we sequenced the genome of a 14,000 year old [Coragyps] occidentalis found associated with megaherbivores in the Peruvian Andes. occidentalis has been viewed as the ancestor, or possibly sister, to the extant Black Vulture Coragyps atratus, but genomic data shows occidentalis to be deeply nested within the South American clade of atratus. Coragyps atratus inhabits lowlands, but the fossil record indicates that occidentalis mostly occupied high elevations. Our results suggest that occidentalis evolved from a population of atratus in southwestern South America that colonized the High Andes 300 to 400 kya. The morphological and morphometric differences between occidentalis and atratus may thus be explained by ecological diversification following from the natural selection imposed by this new and extreme, high elevation environment. The sudden evolution of a population with significantly larger body size and different anatomical proportions than atratus thus constitutes an example of punctuated evolution.
Introduction
Paleogenomics, i.e., the genome-scale sequencing of specimens that are many thousands of years old, has facilitated the study of evolutionary processes at the genetic level in populations that are long gone and has become a valuable complement to the fossil record. Through genetic data, we can clarify phylogenetic relationships of extinct species, test biogeographic and evolutionary hypotheses, and study factors that have led to the extinction of ancient populations and species. Much paleogenomic work of the last decades (e.g., refs. ) has focused on the dynamics and demography of the many species and populations that went extinct at the end of the Pleistocene as a consequence of drastic environmental change and increased hunting pressure. These studies have benefitted from the fact that many extinctions took place in temperate regions where the chance of finding fossils with preserved DNA is particularly good.
The Pliocene and Pleistocene evolution of large herbivores megafauna, such as proboscideans, edentates, camelids, and horses, sparked the co-evolution of various specialized predators, scavengers, parasites, etc., many of which went extinct along with the megaherbivores at the end of the Pleistocene. In the Americas alone, this was the fate of more than thirty species of mammalian and avian predators and scavengers. For example, among the New World Vultures (Cathartidae), only 5 out of 11 genera survived into the Holocene. Herein, we combine genetic and paleontological data to gain insights into the evolution and extinction of one of these fossil birds, the New World Vulture [Coragyps] occidentalis (Miller 1909). We argue that this bird co-evolved with the mammalian megaherbivores during the ice age and that its extinction at the end of the Pleistocene coincides with the extinction of these large herbivores. Read More…
