A High-coverage Ancient Genome for Analyzing Arctic Adaptation Mechanisms – the Steller’s Sea Cow Case

点击翻译按钮获取中文摘要

How organisms respond to climatic and environmental changes is a topic of considerable interest, and considerable effort is spent to explore different scenarios about adaptation. While extant Sirenians (dugongs, manatees) are tropical and subtropical animals, who cannot survive for long in cold or cool water, their extinct relative, the Steller’s sea cow (H. gigas) inhabited cold waters from the northern hemisphere. Intriguingly, the protein that allows non-shivering heat production, UCP1, is missing in all Sirenians, including H. gigas. The mechanism, how H. gigas regulated its body temperature, is unknown. We propose to use the ancient genome of H. gigas for investigating specific traits of Pleistocene arctic adaptation. Recent advances in molecular biology and sequencing technologies made it possible to build an ancient DNA library and already sequence the H. gigas genome to 7.8 times. To have a close reference genome, we will sequence and de novo assemble the dugong genome. By deeper sequencing the H. gigas ancient genome (30 times), we will be able to perform comparative analyses between sea cow, dugong, and manatee and reveal the genetic basis of species-specific traits in H. gigas (e.g. body temperature regulation, lack of digits, increased body size, jaw morphology). Using the diploid genome, we have enough information to model the demographic history and measure the genetic influence of extinct H. gigas on recent Sirenians or vice versa. By sequencing the genome of a species, whose extinction was directly or indirectly driven by wasteful hunting, and assembling the genome of extant endangered relatives, this project will raise awareness on preserving resources, which are mistakenly perceived as "infinite".