Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Genome Biol Evol. 2011;3:641-53. doi: 10.1093/gbe/evr043. Epub 2011 May 13.

Discovery of highly divergent repeat landscapes in snake genomes using high-throughput sequencing.

Author information

  • 1Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, USA.

Abstract

We conducted a comprehensive assessment of genomic repeat content in two snake genomes, the venomous copperhead (Agkistrodon contortrix) and the Burmese python (Python molurus bivittatus). These two genomes are both relatively small (∼1.4 Gb) but have surprisingly extensive differences in the abundance and expansion histories of their repeat elements. In the python, the readily identifiable repeat element content is low (21%), similar to bird genomes, whereas that of the copperhead is higher (45%), similar to mammalian genomes. The copperhead's greater repeat content arises from the recent expansion of many different microsatellites and transposable element (TE) families, and the copperhead had 23-fold greater levels of TE-related transcripts than the python. This suggests the possibility that greater TE activity in the copperhead is ongoing. Expansion of CR1 LINEs in the copperhead genome has resulted in TE-mediated microsatellite expansion ("microsatellite seeding") at a scale several orders of magnitude greater than previously observed in vertebrates. Snakes also appear to be prone to horizontal transfer of TEs, particularly in the copperhead lineage. The reason that the copperhead has such a small genome in the face of so much recent expansion of repeat elements remains an open question, although selective pressure related to extreme metabolic performance is an obvious candidate. TE activity can affect gene regulation as well as rates of recombination and gene duplication, and it is therefore possible that TE activity played a role in the evolution of major adaptations in snakes; some evidence suggests this may include the evolution of venom repertoires.

PMID:
21572095
[PubMed - indexed for MEDLINE]
PMCID:
PMC3157835
Free PMC Article

Images from this publication.See all images (7)Free text

F IG . 1.—
F IG . 2.—
F IG . 3.—
F IG . 4.—
F IG . 5.—
F IG . 6.—
F IG . 7.—
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