Genomic signatures of recombination in a natural population of the bdelloid rotifer Adineta vaga

• Published in: Nature communications Vol. 11; no. 1; p. 6421
• Main Authors: Vakhrusheva, Olga A., Mnatsakanova, Elena A., Galimov, Yan R., Neretina, Tatiana V., Gerasimov, Evgeny S., Naumenko, Sergey A., Ozerova, Svetlana G., Zalevsky, Arthur O., Yushenova, Irina A., Rodriguez, Fernando, Arkhipova, Irina R., Penin, Aleksey A., Logacheva, Maria D., Bazykin, Georgii A., Kondrashov, Alexey S.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 18.12.2020; Nature Publishing Group; Nature Portfolio
• Subjects: 45/22; 45/23; 631/181/2474; 631/181/457/649; 631/181/735; 631/208; 631/208/182; Adineta vaga; Alleles; Animals; Asexuality; Divergence; Eukaryotes; Exchanging; Freshwater invertebrates; Genetic diversity; Genetics, Population; Genome; Genomes; Genotypes; Germ Cells - metabolism; Haplotypes; Haplotypes - genetics; Humanities and Social Sciences; Hybridization; Invertebrates; Linkage disequilibrium; Linkage Disequilibrium - genetics; Loci; multidisciplinary; Phylogeny; Recombination; Recombination, Genetic - genetics; Reproduction; Reproduction (biology); Rotifera; Rotifera - genetics; Science; Science (multidisciplinary); Sexual reproduction; Whole Genome Sequencing
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-19614-y

Sexual reproduction is almost ubiquitous among extant eukaryotes. As most asexual lineages are short-lived, abandoning sex is commonly regarded as an evolutionary dead end. Still, putative anciently asexual lineages challenge this view. One of the most striking examples are bdelloid rotifers, microscopic freshwater invertebrates believed to have completely abandoned sexual reproduction tens of Myr ago. Here, we compare whole genomes of 11 wild-caught individuals of the bdelloid rotifer Adineta vaga and present evidence that some patterns in its genetic variation are incompatible with strict clonality and lack of genetic exchange. These patterns include genotype proportions close to Hardy-Weinberg expectations within loci, lack of linkage disequilibrium between distant loci, incongruent haplotype phylogenies across the genome, and evidence for hybridization between divergent lineages. Analysis of triallelic sites independently corroborates these findings. Our results provide evidence for interindividual genetic exchange and recombination in A. vaga , a species previously thought to be anciently asexual. Ancient, asexual lineages are rare as a lack of recombination is usually an evolutionary dead end. Here, authors compare complete genomes of 11 individual bdelloid rotifers that suggest evidence of regular genetic exchange between individuals in a species that was previously thought to be asexual.