1 / 17

Rethinking the Rotting Y Chromosome

Whitehead Seminars for High School Teachers December 8, 2003. Rethinking the Rotting Y Chromosome. SRY. SRY. SRY. X. Y. X. Y. X. Y. Sex Chromosome Evolution: Y as Rotting X. A pair of autosome s. Nature 415, 963 (2002). The future of sex. R. John Aitken and

jewel
Download Presentation

Rethinking the Rotting Y Chromosome

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Whitehead Seminars for High School Teachers December 8, 2003 Rethinking the Rotting Y Chromosome

  2. SRY SRY SRY X Y X Y X Y Sex Chromosome Evolution: Y as Rotting X A pair of autosomes

  3. Nature 415, 963 (2002) The future of sex R. John Aitken and Jennifer A. Marshal Graves “The Y chromosome is particularly vulnerable … because it is not a matching partner for the X chromosome, so it cannot retrieve lost genetic information by recombination…. The original Y chromosome contained around 1,500 genes, but during the ensuing 300 million years all but about 50 were inactivated or lost…. At the present rate of decay, the Y chromosome will self-destruct in around 10 million years.”

  4. Spermatogenic Specialization of Y Revealed by Genomic Analyses • DNA sequence of chromosome • Catalog of genes • Y deletions  spermatogenic failure

  5. Euchromatin 23 Mb ≈ 1% of human genome Heterochromatin The MSY, the Male-Specific Region of the Human Y Chromosome p q The MSY differs from other nuclear chromosomes: --specific to one sex --no crossing over

  6. X-transposed (99% X-Y identity) X-degenerate Ampliconic MSY Euchromatin: Three Sequence Classes p q Y-specific repeated blocks (amplicons) comprise one third of MSY’s euchromatic DNA Skaletsky et al., Nature 423: 825 (2003)

  7. TSPY RBMY VCY XKRY CDY HSFY PRY BPY2 DAZ 9 Testis-Specific MSY Gene Families: 60 Members, All Located in Amplicons Skaletsky et al., Nature 423: 825 (2003)

  8. And most of the testis genes are in palindromes...

  9. 1 or more testis genes 1 or more testis genes up to 1.5 million bp Structure of an MSY Palindrome 99.9% - 99.99% identity Skaletsky et al., Nature 423: 825 (2003)

  10. 8 Palindromes and 1 Inverted Repeat Comprise 25% of MSY Euchromatin VCY XKRY CDY HSFY RBMY PRY BPY2 DAZ Yq Yp 8 7 6 5 4 IR2 3 2 1 Skaletsky et al., Nature 423: 825 (2003)

  11. Two Forms of Productive Recombination in Human Y Chromosome Male-specific region Yp Yq 1. X-Y crossing-over in pseudoautosomal regions 2. Y-Y gene conversion in portions of MSY consisting of nearly identical sequence pairs, e.g., palindromes

  12. ~76 protein-coding genes  27 distinct proteins; spermatogenic specialization Old and New Understandings of the MSY genetic wasteland gene-rich palindromes of unprecedented scale + precision full of junky repeats no productive recombination  all genes disintegrating (Muller’s Ratchet) gene conversion  method of preserving gene integrity?

More Related