Since the publication of Cairns, Overbaugh, and Miller in
1988 (Nature 335:142-145), John Cairns and I have published two
papers documenting "adaptive" or "directed" mutations in E. coli.
The references are:
Cairns and Foster. 1991. Genetics 128:695-701
Foster and Cairns. 1992. Genetics 131:783-789.
In the first paper, we describe experiments in which we
carefully controlled for the confounding factors that critics
have cited, including the ones discussed by Lenski & Mittler
in their recent review article (Science 1993. 259:188-194).
In the second paper we provide evidence against several of the
current models for adaptive mutation, including reverse-
information flow (Cairns et al, ibid.), mutagenic transcription
(Davis, 1989. PNAS 86:5005-5009), and slow DNA repair (Stahl,
1988. Nature 335:112-113). In their review article, Lenski &
Mittler do not discuss our experiments. Interestingly, however,
they do accept our conclusions about the models. Thus, they
are implying that our experiments are flawed, without explicitly
saying how, and, at the same time, believing the results of those
Since many scientist outside of the field of bacterial genetics are
interested in this subject, it is probably inevitable that information
is obtained from review articles instead of from primary papers. But,
I urge those who are interested to at least avail themselves of
reviews written by people who are willing to keep an open mind and to
consider all the evidence. I suggest the following articles (immodestly
including my own):
Drake 1991 Annu. Rev. Genet. 25:125-145
Foster 1992 J. Bacteriol. 174:1711-1716
(I will have a longer review in Annu. Rev. Microbiol. this year)
Symonds 1993 Mutat. Res. 285:9-12
I also recommend Keller's wonderful article
In the more popular press:
Symonds 1991. New Scientist 1787:30-34
Goodman, 1992 Mosaic 23:24-33.
Patricia L. Foster
Boston University School of Public Health
Boston University School of Medicine
80 E. Concord St.
Boston, MA 02118
email: pfoster at med-itvax1.bu.edu