Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Genetics. 2007 Mar;175(3):1335-40. Epub 2006 Dec 28.

Evolution of different Y chromosomes in two medaka species, Oryzias dancena and O. latipes.

Author information

  • 1Graduate School of Science and Technology, Niigata University, Ikarashi, Niigata 950-2181, Japan. yusuke@env.sc.niigata-u.ac.jp

Abstract

Although the sex-determining gene DMY has been identified on the Y chromosome in the medaka (Oryzias latipes), this gene is absent in most Oryzias species, suggesting that closely related species have different sex-determining genes. Here, we investigated the sex-determination mechanism in O. dancena, which does not possess the DMY gene. Since heteromorphic sex chromosomes have not been reported in this species, a progeny test of sex-reversed individuals produced by hormone treatment was performed. Sex-reversed males yielded all-female progeny, indicating that O. dancena has an XX/XY sex-determination system. To uncover the cryptic sex chromosomes, sex-linked DNA markers were screened using expressed sequence tags (ESTs) established in O. latipes. Linkage analysis of isolated sex-linked ESTs showed a conserved synteny between the sex chromosomes in O. dancena and an autosome in O. latipes. Fluorescence in situ hybridization (FISH) analysis of these markers confirmed that sex chromosomes of these species are not homologous. These findings strongly suggest an independent origin of sex chromosomes in O. dancena and O. latipes. Further analysis of the sex-determining region in O. dancena should provide crucial insights into the evolution of sex-determination mechanisms in vertebrates.

PMID:
17194774
[PubMed - indexed for MEDLINE]
PMCID:
PMC1840079
Free PMC Article

Images from this publication.See all images (4)Free text

F igure  1.—
F igure  2.—
F igure  3.—
F igure  4.—
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk