TY - JOUR
T1 - Anisogamy evolved with a reduced sex-determining region in volvocine green algae
AU - Hamaji, Takashi
AU - Kawai-Toyooka, Hiroko
AU - Uchimura, Haruka
AU - Suzuki, Masahiro
AU - Noguchi, Hideki
AU - Minakuchi, Yohei
AU - Toyoda, Atsushi
AU - Fujiyama, Asao
AU - Miyagishima, Shin ya
AU - Umen, James G.
AU - Nozaki, Hisayoshi
N1 - Publisher Copyright:
© 2018, The Author(s).
PY - 2018/12/1
Y1 - 2018/12/1
N2 - Male and female gametes differing in size—anisogamy—emerged independently from isogamous ancestors in various eukaryotic lineages, although genetic bases of this emergence are still unknown. Volvocine green algae are a model lineage for investigating the transition from isogamy to anisogamy. Here we focus on two closely related volvocine genera that bracket this transition—isogamous Yamagishiella and anisogamous Eudorina. We generated de novo nuclear genome assemblies of both sexes of Yamagishiella and Eudorina to identify the dimorphic sex-determining chromosomal region or mating-type locus (MT) from each. In contrast to the large (>1 Mb) and complex MT of oogamous Volvox, Yamagishiella and Eudorina MT are smaller (7–268 kb) and simpler with only two sex-limited genes—the minus/male-limited MID and the plus/female-limited FUS1. No prominently dimorphic gametologs were identified in either species. Thus, the first step to anisogamy in volvocine algae presumably occurred without an increase in MT size and complexity.
AB - Male and female gametes differing in size—anisogamy—emerged independently from isogamous ancestors in various eukaryotic lineages, although genetic bases of this emergence are still unknown. Volvocine green algae are a model lineage for investigating the transition from isogamy to anisogamy. Here we focus on two closely related volvocine genera that bracket this transition—isogamous Yamagishiella and anisogamous Eudorina. We generated de novo nuclear genome assemblies of both sexes of Yamagishiella and Eudorina to identify the dimorphic sex-determining chromosomal region or mating-type locus (MT) from each. In contrast to the large (>1 Mb) and complex MT of oogamous Volvox, Yamagishiella and Eudorina MT are smaller (7–268 kb) and simpler with only two sex-limited genes—the minus/male-limited MID and the plus/female-limited FUS1. No prominently dimorphic gametologs were identified in either species. Thus, the first step to anisogamy in volvocine algae presumably occurred without an increase in MT size and complexity.
UR - http://www.scopus.com/inward/record.url?scp=85051928319&partnerID=8YFLogxK
U2 - 10.1038/s42003-018-0019-5
DO - 10.1038/s42003-018-0019-5
M3 - Article
C2 - 30271904
AN - SCOPUS:85051928319
SN - 2399-3642
VL - 1
JO - Communications Biology
JF - Communications Biology
IS - 1
M1 - 17
ER -