More "natural evil?"

Noticed this after reading the exchange
concerning God's responsibility for "natural
evil." Interesting that the putative defects were
generated so far back. But maybe Glenn could say
that they occurred after the fall of his very old
Adam. (Not that I would put words in Glenn's
mouth. I know better than that!) :)

Preston G.

Evidence for Widespread Degradation of Gene Control Regions in Hominid Genomes

Peter D. Keightley1* , Martin J. Lercher2 , Adam Eyre-Walker3

1 School of Biological Sciences, University of
Edinburgh, Edinburgh, United Kingdom, 2
Department of Biology and Biochemistry,
University of Bath, Bath, United Kingdom, 3
Centre for the Study of Evolution and School of
Life Sciences, University of Sussex, Brighton,
United Kingdom

Although sequences containing regulatory elements
located close to protein-coding genes are often
only weakly conserved during evolution,
comparisons of rodent genomes have implied that
these sequences are subject to some selective
constraints. Evolutionary conservation is
particularly apparent upstream of coding
sequences and in first introns, regions that are
enriched for regulatory elements. By comparing
the human and chimpanzee genomes, we show here
that there is almost no evidence for conservation
in these regions in hominids. Furthermore, we
show that gene expression is diverging more
rapidly in hominids than in murids per unit of
neutral sequence divergence. By combining data on
polymorphism levels in human noncoding DNA and
the corresponding human-chimpanzee divergence, we
show that the proportion of adaptive
substitutions in these regions in hominids is
very low. It therefore seems likely that the lack
of conservation and increased rate of gene
expression divergence are caused by a reduction
in the effectiveness of natural selection against
deleterious mutations because of the low
effective population sizes of hominids. This has
resulted in the accumulation of a large number of
deleterious mutations in sequences containing
gene control elements and hence a widespread
degradation of the genome during the evolution of
humans and chimpanzees.

Received August 30, 2004; Accepted December 1, 2004; Published January 25, 2005

DOI: 10.1371/journal.pbio.0030042

Copyright: © 2005 Keightley et al. This is an
open-access article distributed under the terms
of the Creative Commons Attribution License,
which permits unrestricted use, distribution, and
reproduction in any medium, provided the original
work is properly cited.

Academic Editor: Monty Slatkin, University of
California at Berkeley, United States of America

*To whom correspondence should be addressed.
E-mail: Hominid.Degradation@spambob.net

Citation: Keightley PD, Lercher MJ, Eyre-Walker A
(2005) Evidence for Widespread Degradation of
Gene Control Regions in Hominid Genomes. PLoS
Biol 3(2): e42
Received on Thu Feb 3 00:41:32 2005