Sophia Ahmed1, J Mark Cock2, Eugenie Pessia3, Remy Luthringer2, Alexandre Cormier2, Marine Robuchon4, Lieven Sterck5, Akira F Peters6, Simon M Dittami2, Erwan Corre7, Myriam Valero8, Jean-Marc Aury9, Denis Roze8, Yves Van de Peer10, John Bothwell11, Gabriel A B Marais3, Susana M Coelho12. 1. Integrative Biology of Marine Models, CNRS UMR 8227, Sorbonne Universités, UPMC Université Paris 6, Station Biologique de Roscoff, CS 90074, 29688 Roscoff, France; Medical Biology Centre, Queens University Belfast, Belfast BT9 7BL, Northern Ireland, UK. 2. Integrative Biology of Marine Models, CNRS UMR 8227, Sorbonne Universités, UPMC Université Paris 6, Station Biologique de Roscoff, CS 90074, 29688 Roscoff, France. 3. Laboratoire de Biométrie et Biologie Évolutive, UMR 5558, Centre National de la Recherche Scientifique, Université Lyon 1, 69622 Villeurbanne, France. 4. Integrative Biology of Marine Models, CNRS UMR 8227, Sorbonne Universités, UPMC Université Paris 6, Station Biologique de Roscoff, CS 90074, 29688 Roscoff, France; Evolutionary Biology and Ecology of Algae, CNRS UMI 3604, Sorbonne Université, UPMC, PUCCh, UACH, Station Biologique de Roscoff, CS 90074, 29688 Roscoff, France. 5. Department of Plant Systems Biology (VIB) and Department of Plant Biotechnology and Bioinformatics (Ghent University), Technologiepark 927, 9052 Gent, Belgium. 6. Bezhin Rosko, 29250 Santec, France. 7. ABiMS Platform, FR2424, Station Biologique de Roscoff, CS 90074, 29688 Roscoff, France. 8. Evolutionary Biology and Ecology of Algae, CNRS UMI 3604, Sorbonne Université, UPMC, PUCCh, UACH, Station Biologique de Roscoff, CS 90074, 29688 Roscoff, France. 9. Commissariat à l'Energie Atomique (CEA), Institut de Génomique (IG), Genoscope, 91000 Evry, France. 10. Department of Plant Systems Biology (VIB) and Department of Plant Biotechnology and Bioinformatics (Ghent University), Technologiepark 927, 9052 Gent, Belgium; Genomics Research Institute, University of Pretoria, Hatfield Campus, Pretoria 0028, South Africa. 11. Medical Biology Centre, Queens University Belfast, Belfast BT9 7BL, Northern Ireland, UK. 12. Integrative Biology of Marine Models, CNRS UMR 8227, Sorbonne Universités, UPMC Université Paris 6, Station Biologique de Roscoff, CS 90074, 29688 Roscoff, France. Electronic address: coelho@sb-roscoff.fr.
Abstract
BACKGROUND: A common feature of most genetic sex-determination systems studied so far is that sex is determined by nonrecombining genomic regions, which can be of various sizes depending on the species. These regions have evolved independently and repeatedly across diverse groups. A number of such sex-determining regions (SDRs) have been studied in animals, plants, and fungi, but very little is known about the evolution of sexes in other eukaryotic lineages. RESULTS: We report here the sequencing and genomic analysis of the SDR of Ectocarpus, a brown alga that has been evolving independently from plants, animals, and fungi for over one giga-annum. In Ectocarpus, sex is expressed during the haploid phase of the life cycle, and both the female (U) and the male (V) sex chromosomes contain nonrecombining regions. The U and V of this species have been diverging for more than 70 mega-annum, yet gene degeneration has been modest, and the SDR is relatively small, with no evidence for evolutionary strata. These features may be explained by the occurrence of strong purifying selection during the haploid phase of the life cycle and the low level of sexual dimorphism. V is dominant over U, suggesting that femaleness may be the default state, adopted when the male haplotype is absent. CONCLUSIONS: The Ectocarpus UV system has clearly had a distinct evolutionary trajectory not only to the well-studied XY and ZW systems but also to the UV systems described so far. Nonetheless, some striking similarities exist, indicating remarkable universality of the underlying processes shaping sex chromosome evolution across distant lineages.
BACKGROUND: A common feature of most genetic sex-determination systems studied so far is that sex is determined by nonrecombining genomic regions, which can be of various sizes depending on the species. These regions have evolved independently and repeatedly across diverse groups. A number of such sex-determining regions (SDRs) have been studied in animals, plants, and fungi, but very little is known about the evolution of sexes in other eukaryotic lineages. RESULTS: We report here the sequencing and genomic analysis of the SDR of Ectocarpus, a brown alga that has been evolving independently from plants, animals, and fungi for over one giga-annum. In Ectocarpus, sex is expressed during the haploid phase of the life cycle, and both the female (U) and the male (V) sex chromosomes contain nonrecombining regions. The U and V of this species have been diverging for more than 70 mega-annum, yet gene degeneration has been modest, and the SDR is relatively small, with no evidence for evolutionary strata. These features may be explained by the occurrence of strong purifying selection during the haploid phase of the life cycle and the low level of sexual dimorphism. V is dominant over U, suggesting that femaleness may be the default state, adopted when the male haplotype is absent. CONCLUSIONS: The Ectocarpus UV system has clearly had a distinct evolutionary trajectory not only to the well-studied XY and ZW systems but also to the UV systems described so far. Nonetheless, some striking similarities exist, indicating remarkable universality of the underlying processes shaping sex chromosome evolution across distant lineages.
Authors: James E Tarver; Alexandre Cormier; Natalia Pinzón; Richard S Taylor; Wilfrid Carré; Martina Strittmatter; Hervé Seitz; Susana M Coelho; J Mark Cock Journal: Nucleic Acids Res Date: 2015-06-22 Impact factor: 16.971
Authors: Sarah B Carey; Jerry Jenkins; John T Lovell; Florian Maumus; Avinash Sreedasyam; Adam C Payton; Shengqiang Shu; George P Tiley; Noe Fernandez-Pozo; Adam Healey; Kerrie Barry; Cindy Chen; Mei Wang; Anna Lipzen; Chris Daum; Christopher A Saski; Jordan C McBreen; Roth E Conrad; Leslie M Kollar; Sanna Olsson; Sanna Huttunen; Jacob B Landis; J Gordon Burleigh; Norman J Wickett; Matthew G Johnson; Stefan A Rensing; Jane Grimwood; Jeremy Schmutz; Stuart F McDaniel Journal: Sci Adv Date: 2021-06-30 Impact factor: 14.136