Three sex phenotypes in a haploid algal species give insights into the evolutionary transition to a self‐compatible mating system*

• DOI: 10.1111/evo.14306
• Publication Date: 2021-07-12T04:09:00Z
• Authors: Kohei Takahashi; Hiroko Kawai‐Toyooka; Ryo Ootsuki; Takashi Hamaji; Yuki Tsuchikane; Hiroyuki Sekimoto; Tetsuya Higashiyama; Hisayoshi Nozaki
• Keywords: Male; 0303 health sciences; 03 medical and health sciences; Phenotype; Reproduction; Humans; Female; Haploidy; Brief Communications; Biological Evolution

Mating systems of haploid species such as fungi, algae, and bryophytes are either heterothallic (self-incompatible) with two sex phenotypes (male female, or mating type minus plus in isogamous species) homothallic (self-compatible) only a bisexual phenotype producing zygotes within clone. The anisogamous volvocine green alga Pleodorina starrii is previously reported to have system. Here, we found that additional culture strains originating from the same water system P. were taxonomically identified produced male female gametes clone (bisexual). Sequences rapidly evolving plastid genome regions identical between unisexual female) strains. Intercrossings demonstrated normal thick-walled high survivability F1 Thus, these belong biological species. has new unique having three phenotypes, namely, male, bisexual. Genetic analyses suggested existence autosomal "bisexual factor" locus independent determining regions. present findings increase our understanding initial evolutionary step transition heterothallism homothallism.