A key role for sex chromosomes in the regulation of parthenogenesis in the brown alga Ectocarpus

• DOI: 10.1371/journal.pgen.1008211
• Publication Date: 2019-06-13T17:29:29Z
• Authors: Laure Mignerot; Komlan Avia; Remy Luthringer; Agnieszka P. Lipi...; Akira F. Peters; J. Mark Cock; Susana M. Coelho
• Keywords: 0301 basic medicine; Quantitative trait loci; Algae; Phaeophyceae; Genetic loci; [SDV]Life Sciences [q-bio]; Parthenogenesis; Quantitative Trait Loci; fluctuating selection;read alignment ;apomixis ;loci ;evolution; reproduction; genome ;establishment; polymorphism ;maintenance; QH426-470; Haploidy; 03 medical and health sciences; Reproduction, Asexual; Genetics; [SDV.BV]Life Sciences [q-bio]/Vegetal Biology; Gene mapping; Alleles; [SDV.GEN]Life Sciences [q-bio]/Genetics; Life Cycle Stages; 0303 health sciences; Genome; Polymorphism, Genetic; Sex Chromosomes; Sequence assembly tools; Sex chromosomes; Biological Evolution; [SDE]Environmental Sciences; Research Article

AbstractAlthough evolutionary transitions from sexual to asexual reproduction are frequent in eukaryotes, the genetic bases of these shifts remain largely elusive. Here, we used classic quantitative trait analysis, combined with genomic and transcriptomic information to dissect the genetic basis of asexual, parthenogenetic reproduction in the brown algaEctocarpus. We found that parthenogenesis is controlled by the sex locus, together with two additional autosomal loci, highlight the key role of the sex chromosome as a major regulator of asexual reproduction. Importantly, we identify several negative effects of parthenogenesis on male fitness, but also different fitness effects between parthenogenesis and life cycle generations, supporting the idea that parthenogenesis may be under both sexual selection and generation/ploidally-antagonistic selection. Overall, our data provide the first empirical illustration, to our knowledge, of a trade-off between the haploid and diploid stages of the life cycle, where distinct parthenogenesis alleles have opposing effects on sexual and asexual reproduction and may contribute to the maintenance of genetic variation. These types of fitness trade-offs have profound evolutionary implications in natural populations and may structure life history evolution in organisms with haploid-diploid life cycles.