Strand Asymmetries in DNA Evolution
M. Phlar Francino and Howard Ochman
Department of Biology, University of Rochester, NY 14627, USA.
pilar@ho-lab.biology.rochester.edu
Trends in Genetics, 13(6), 240-245 (June 1997).
Abstract
The complementary strands of DNA differ with respect to
replication and transcription. Both of these processes
are asymmetric and can bias the occurrence of mutations
between the strands: during replication, the discontinuous
lagging strand undergoes certain errors at higher rates,
and transcription overexposes the nontranscribed strand to
DNA damage while targeting repair enzymes to the transcribed
strand. While biases introduced during replication apparently
have little impact on sequence evolution, the effects of
transcription are observed in the asymmetric patterns of
substitution in bacterial genes and might be influencing
genome-wide patterns of base composition.
