Multiple mechanisms drive genomic adaptation to extreme O2 levels in Drosophila melanogaster

• Published in: Nature communications 2021-02, Vol.12 (1), p.1-10, Article 997
• Main Authors: Iranmehr, Arya, Stobdan, Tsering, Zhou, Dan, Zhao, Huiwen, Kryazhimskiy, Sergey, Bafna, Vineet, Haddad, Gabriel G.
• Format: Article
• Language: English
• Subjects: 45; 45/23; 631/181/2475; 631/208/182; 64; 64/24; Adaptation; Drosophila melanogaster; Extreme environments; Fruit flies; Gene sequencing; Genomes; Haplotypes; Harsh environments; Humanities and Social Sciences; Insects; multidisciplinary; Mutation; Recombination; Reproduction (biology); Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-21281-6

To detect the genomic mechanisms underlying evolutionary dynamics of adaptation in sexually reproducing organisms, we analyze multigenerational whole genome sequences of Drosophila melanogaster adapting to extreme O 2 conditions over an experiment conducted for nearly two decades. We develop methods to analyze time-series genomics data and predict adaptive mechanisms. Here, we report a remarkable level of synchronicity in both hard and soft selective sweeps in replicate populations as well as the arrival of favorable de novo mutations that constitute a few asynchronized sweeps. We additionally make direct experimental observations of rare recombination events that combine multiple alleles on to a single, better-adapted haplotype. Based on the analyses of the genes in genomic intervals, we provide a deeper insight into the mechanisms of genome adaptation that allow complex organisms to survive harsh environments. The genomic details of adaptation to extreme environments remain challenging to characterize. Using new methods to analyze flies experimentally evolved to survive extreme O 2 conditions, the authors find a surprising level of synchronicity in selective sweeps, de novo mutations and adaptive recombination events.