Yamamoto Kayoko, Matsuzaki Ryo, Mahakham Wuttipong, Heman Wirawan, Sekimoto Hiroyuki, Kawachi Masanobu, Minakuchi Yohei, Toyoda Atsushi, Nozaki Hisayoshi
Department of Chemical and Biological Sciences, Faculty of Science, Japan Women's University, Tokyo 112-8681 Japan.
Biodiversity Division, National Institute for Environmental Studies, Tsukuba 305-8506, Japan.
iScience. 2023 Jun 1;26(6):106893. doi: 10.1016/j.isci.2023.106893. eCollection 2023 Jun 16.
Male and female genotypes in heterothallic (self-incompatible) species of haploid organisms, such as algae and bryophytes, are generally determined by male and female sex-determining regions (SDRs) in the sex chromosomes. To resolve the molecular genetic basis for the evolution of homothallic (bisexual and self-compatible) species from a heterothallic ancestor, we compared whole-genome data from Thai and Japanese genotypes within the homothallic green alga . The Thai and Japanese algae harbored expanded ancestral male and female SDRs of ∼1 Mbp each, representing a direct heterothallic ancestor. Therefore, the expanded male and female ancestral SDRs may originate from the ancient (∼75 mya) heterothallic ancestor, and either might have been conserved during the evolution of each homothallic genotype. An expanded SDR-like region seems essential for homothallic sexual reproduction in , irrespective of male or female origin. Our study stimulates future studies to elucidate the biological significance of such expanded genomic regions.
在单倍体生物的异宗配合（自交不亲和）物种中，如藻类和苔藓植物，雄性和雌性基因型通常由性染色体上的雄性和雌性性别决定区域（SDR）决定。为了解决从异宗配合祖先进化而来的同宗配合（两性且自交亲和）物种的分子遗传基础问题，我们比较了同宗配合绿藻中泰国和日本基因型的全基因组数据。泰国和日本的藻类各自拥有扩展的祖先雄性和雌性SDR，约为1兆碱基对，代表了一个直接的异宗配合祖先。因此，扩展的雄性和雌性祖先SDR可能起源于古老的（约7500万年前）异宗配合祖先，并且在每个同宗配合基因型的进化过程中可能都得到了保留。一个类似SDR的扩展区域似乎对同宗配合的有性生殖至关重要，无论其起源于雄性还是雌性。我们的研究激发了未来的研究，以阐明此类扩展基因组区域的生物学意义。
