Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Proc Natl Acad Sci U S A. 2002 Oct 1;99(20):12944-8. Epub 2002 Sep 16.

Acceleration of genomic evolution caused by enhanced mutation rate in endocellular symbionts.

Author information

  • 1Institute of Molecular Evolutionary Genetics and Department of Biology, Pennsylvania State University, 328 Mueller Laboratory, University Park, PA 16802, USA.

Abstract

Endosymbionts, which are widely observed in nature, have undergone reductive genome evolution because of their long-term intracellular lifestyle. Here we compared the complete genome sequences of two different endosymbionts, Buchnera and a protist mitochondrion, with their close relatives to study the evolutionary rates of functional genes in endosymbionts. The results indicate that the rate of amino acid substitution is two times higher in symbionts than in their relatives. This rate increase was observed uniformly among different functional classes of genes, although strong purifying selection may have counterbalanced the rate increase in a few cases. Our data suggest that, contrary to current views, neither the Muller's ratchet effect nor the slightly deleterious mutation theory sufficiently accounts for the elevated evolutionary rate. Rather, the elevated evolutionary rate appears to be mainly due to enhanced mutation rate, although the possibility of relaxation of purifying selection cannot be ruled out.

PMID:
12235368
[PubMed - indexed for MEDLINE]
PMCID:
PMC130565
Free PMC Article

Images from this publication.See all images (2)Free text

Figure 1
Figure 2
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

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