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 - Funding Information:
We thank the staff of Comparative Genomics Laboratory at NIG for supporting genome sequencing. Computations were partially performed on the NIG supercomputer at ROIS National Institute of Genetics. This work was supported by a Grants-in-Aid for Scientific Research on Innovative Areas “Genome Science” (grant number 221S0002; to A.T. and A.F.), Scientific Research (A) (grant number 16H02518; to H.Nozaki), Research Activity Startup grants (grant number 16H06734 to T.H.), Scientific Research (C) (grant number 17K07510 to H.K.-T.), Grant-in-Aid for Scientific Research on Innovative Areas (grant number 17H05840 to T.H.) from MEXT/JSPS KAKENHI, and National Institutes of Health (grant number GM 078376 to J.G.U.).
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 -