The Y Chromosome in the Liverwort Marchantia polymorpha has Accumulated Unique Repeat Sequences Harboring a Male-Specific Gene

• Published in: Proceedings of the National Academy of Sciences - PNAS 2001-07, Vol.98 (16), p.9454-9459
• Main Authors: Okada, Sachiko, Sone, Takefumi, Fujisawa, Masaki, Nakayama, Shigeki, Takenaka, Mizuki, Ishizaki, Kimitsune, Kono, Kaoru, Shimizu-Ueda, Yuu, Hanajiri, Tsutomu, Yamato, Katsuyuki T., Fukuzawa, Hideya, Brennicke, Axel, Ohyama, Kanji
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Base Sequence; Biological Sciences; Chromosome Mapping; Chromosome polymorphism; Chromosomes; Chromosomes, Artificial; DNA; DNA, Plant; Evolution; Flowers & plants; Genes; Genomes; Genomics; In Situ Hybridization, Fluorescence; Magnoliopsida - genetics; Marchantia polymorpha; Molecular Sequence Data; Open Reading Frames; Plants; Polymerase Chain Reaction; Proteins; Sequence Homology, Amino Acid; Sex chromosomes; Sexes; Y Chromosome
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.171304798

The haploid liverwort Marchantia polymorpha has heteromorphic sex chromosomes, an X chromosome in the female and a Y chromosome in the male. We here report on the repetitive structure of the liverwort Y chromosome through the analysis of male-specific P1-derived artificial chromosome (PAC) clones, pMM4G7 and pMM23-130F12. Several chromosome-specific sequence elements of ≈70 to 400 nt are combined into larger arrangements, which in turn are assembled into extensive Y chromosome-specific stretches. These repeat sequences contribute 2-3 Mb to the Y chromosome based on the observations of three different approaches: fluorescence in situ hybridization, dot blot hybridization, and the frequency of clones containing the repeat sequences in the genomic library. A novel Y chromosome-specific gene family was found embedded among these repeat sequences. This gene family encodes a putative protein with a RING finger motif and is expressed specifically in male sexual organs. To our knowledge, there have been no other reports for an active Y chromosome-specific gene in plants. The chromosome-specific repeat sequences possibly contribute to determining the identity of the Y chromosome in M. polymorpha as well as to maintaining genes required for male functions, as in mammals such as human.