Display Settings:


Send to:

Choose Destination
See comment in PubMed Commons below
Genome Res. 2008 Dec;18(12):1938-43. doi: 10.1101/gr.078808.108. Epub 2008 Jul 1.

DNA methylation and heterochromatinization in the male-specific region of the primitive Y chromosome of papaya.

Author information

  • 1Department of Horticulture, University of Wisconsin, Madison, Wisconsin 53706, USA.


Sex chromosomes evolved from autosomes. Recombination suppression in the sex-determining region and accumulation of deleterious mutations lead to degeneration of the Y chromosomes in many species with heteromorphic X/Y chromosomes. However, how the recombination suppressed domain expands from the sex-determining locus to the entire Y chromosome remains elusive. The Y chromosome of papaya (Carica papaya) diverged from the X chromosome approximately 2-3 million years ago and represents one of the most recently emerged Y chromosomes. Here, we report that the male-specific region of the Y chromosome (MSY) spans approximately 13% of the papaya Y chromosome. Interestingly, the centromere of the Y chromosome is embedded in the MSY. The centromeric domain within the MSY has accumulated significantly more DNA than the corresponding X chromosomal domain, which leads to abnormal chromosome pairing. We observed four knob-like heterochromatin structures specific to the MSY. Fluorescence in situ hybridization and immunofluorescence assay revealed that the DNA sequences associated with the heterochromatic knobs are highly divergent and heavily methylated compared with the sequences in the corresponding X chromosomal domains. These results suggest that DNA methylation and heterochromatinization play an important role in the early stage of sex chromosome evolution.

[PubMed - indexed for MEDLINE]
Free PMC Article

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

Figure 1.
Figure 2.
Figure 3.
Figure 4.
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

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