title: Multicopy genes uniquely amplified in the Y chromosome-specific repeats of the liverwort Marchantia polymorpha.
abstract: Sex of the liverwort Marchantia polymorpha is determined by the sex chromosomes Y and X, in male and female plant, respectively. Approximately half of the Y chromosome is made up of unique repeat sequences. Here, we report that part of the Y chromosome, represented by a 90-kb insert of a genomic clone pMM2D3, contains five putative genes in addition to the ORF162 gene, which is present also within the Y chromosome-specific repeat region. One of the five putative genes shows similarity to a male gamete-specific protein of lily and is expressed predominantly in male sex organs, suggesting that this gene has a male reproductive function. Furthermore, Southern blot analysis revealed that these five putative genes are amplified on the Y chromosome, but they also probably have homologs on the X chromosome and/or autosomes. These observations suggest that the Y chromosome evolved by co-amplifying protein-coding genes with unique repeat sequences.
authors.affiliation: Laboratory of Plant Molecular Biology, Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan.
authors.forename: Kimitsune
authors.initials: K
authors.lastname: Ishizaki
authors.forename: Yuu
authors.initials: Y
authors.lastname: Shimizu-Ueda
authors.forename: Sachiko
authors.initials: S
authors.lastname: Okada
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Masaki
authors.initials: M
authors.lastname: Fujisawa
authors.forename: Katsuyuki T
authors.initials: KT
authors.lastname: Yamato
authors.forename: Hideya
authors.initials: H
authors.lastname: Fukuzawa
authors.forename: Kanji
authors.initials: K
authors.lastname: Ohyama
mesh_terms: D000595:Amino Acid Sequence; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics*; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics; D005784:Gene Amplification; D018628:Gene Dosage; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics*; D035926:Hepatophyta / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D016366:Open Reading Frames / Q000235:genetics; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics; D017434:Protein Structure, Tertiary; D018749:RNA, Plant / Q000032:analysis / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics*; D016415:Sequence Alignment; D014158:Transcription, Genetic; D014998:Y Chromosome / Q000235:genetics*
chemical_list: D004268:DNA-Binding Proteins; D010940:Plant Proteins; D018749:RNA, Plant