Gene organization of the liverwort Y chromosome reveals distinct sex chromosome evolution in a haploid system.
Y chromosomes are different from other chromosomes because of a lack of recombination. Until now, complete sequence information of Y chromosomes has been available only for some primates, although considerable information is available for other organisms, e.g., several species of Drosophila. Here, we report the gene organization of the Y chromosome in the dioecious liverwort Marchantia polymorpha and provide a detailed view of a Y chromosome in a haploid organism. On the 10-Mb Y chromosome, 64 genes are identified, 14 of which are detected only in the male genome and are expressed in reproductive organs but not in vegetative thalli, suggesting their participation in male reproductive functions. Another 40 genes on the Y chromosome are expressed in thalli and male sexual organs. At least six of these genes have diverged X-linked counterparts that are in turn expressed in thalli and sexual organs in female plants, suggesting that these X- and Y-linked genes have essential cellular functions. These findings indicate that the Y and X chromosomes share the same ancestral autosome and support the prediction that in a haploid organism essential genes on sex chromosomes are more likely to persist than in a diploid organism.
Yamato
Katsuyuki T
KT
Laboratory of Plant Molecular Biology, Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan.
Ishizaki
Kimitsune
K
Fujisawa
Masaki
M
Okada
Sachiko
S
Nakayama
Shigeki
S
Fujishita
Mariko
M
Bando
Hiroki
H
Yodoya
Kohei
K
Hayashi
Kiwako
K
Bando
Tomoyuki
T
Hasumi
Akiko
A
Nishio
Tomohisa
T
Sakata
Ryoko
R
Yamamoto
Masayuki
M
Yamaki
Arata
A
Kajikawa
Masataka
M
Yamano
Takashi
T
Nishide
Taku
T
Choi
Seung-Hyuk
SH
Shimizu-Ueda
Yuu
Y
Hanajiri
Tsutomu
T
Sakaida
Megumi
M
Kono
Kaoru
K
Takenaka
Mizuki
M
Yamaoka
Shohei
S
Kuriyama
Chiaki
C
Kohzu
Yoshito
Y
Nishida
Hiroyuki
H
Brennicke
Axel
A
Shin-i
Tadasu
T
Kohara
Yuji
Y
Kohchi
Takayuki
T
Fukuzawa
Hideya
H
Ohyama
Kanji
K
D001483:Base Sequence; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics*; D019143:Evolution, Molecular; D020224:Expressed Sequence Tags; D017343:Genes, Plant / Q000235:genetics*; D006238:Haploidy; D035926:Hepatophyta / Q000235:genetics*; D017404:In Situ Hybridization, Fluorescence; D008969:Molecular Sequence Data; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA