LTR Retroelements and Bird Adaptation to Arid Environments

Abstract

TEs are known to be among the main drivers in genome evolution, leading to the generation of evolutionary advantages that favor the success of organisms. The aim of this work was to investigate the TE landscape in bird genomes to look for a possible relationship between the amount of specific TE types and environmental changes that characterized the Oligocene era in Australia. Therefore, the mobilome of 29 bird species, belonging to a total of 11 orders, was analyzed. Our results confirmed that LINE retroelements are not predominant in all species of this evolutionary lineage and highlighted an LTR retroelement dominance in species with an Australian-related evolutionary history. The bird LTR retroelement expansion might have happened in response to the Earth’s dramatic climate changes that occurred about 30 Mya, followed by a progressive aridification across most of Australian landmasses. Therefore, in birds, LTR retroelement burst might have represented an evolutionary advantage in the adaptation to arid/drought environments.

Nine high-quality Anas genomes provide new insights into Anas evolution and domestication

“…Thirdly, our study highlighted an LTR-RT burst in the wild ancestors of domestic ducks, and the evolutionary signatures, such as SNP density, around intact-LTR regions. Previous studies have shown that LTR-RT burst was related to the environment adaption in birds (45), and here we found that LTR-RT burst might be involved in duck domestication. For example, some Pekin or domestic specific intact-LTRs potentially regulate the expression of their neighbor genes associated with animal domestication, including IGF2BP1 for increasing body size (13), MITF for feather color changing (13), PCDH15 for adapting environment (35) and ANXA5 for enhancing productive ability (33).…”