Beneficial fitness effects are not exponential for two viruses.
The distribution of fitness effects for beneficial mutations is of paramount importance in determining the outcome of adaptation. It is generally assumed that fitness effects of beneficial mutations follow an exponential distribution, for example, in theoretical treatments of quantitative genetics, clonal interference, experimental evolution, and the adaptation of DNA sequences. This assumption has been justified by the statistical theory of extreme values, because the fitnesses conferred by beneficial mutations should represent samples from the extreme right tail of the fitness distribution. Yet in extreme value theory, there are three different limiting forms for right tails of distributions, and the exponential describes only those of distributions in the Gumbel domain of attraction. Using beneficial mutations from two viruses, we show for the first time that the Gumbel domain can be rejected in favor of a distribution with a right-truncated tail, thus providing evidence for an upper bound on fitness effects. Our data also violate the common assumption that small-effect beneficial mutations greatly outnumber those of large effect, as they are consistent with a uniform distribution of beneficial effects.
Rokyta
Darin R
DR
Department of Biological Sciences, University of Idaho, P.O. Box 443051, Moscow, ID 83844-3051, USA.
Beisel
Craig J
CJ
Joyce
Paul
P
Ferris
Martin T
MT
Burch
Christina L
CL
Wichman
Holly A
HA
D001435:Bacteriophages / Q000235:genetics*; D005075:Biological Evolution; D030541:Databases, Genetic; D009154:Mutation / Q000235:genetics; D012641:Selection, Genetic
Genetics. 2003 Apr;163(4):1519-26
12702694
Nat Genet. 2005 Apr;37(4):441-4
15778707
Evolution. 1984 Sep;38(5):1116-1129
28555784
Genetics. 2006 Apr;172(4):2047-56
16361237
Nat Genet. 2006 Apr;38(4):484-8
16550173
Genetics. 2005 Nov;171(3):1377-86
16020775
Nat Rev Genet. 2005 Feb;6(2):119-27
15716908
Genetics. 1985 Nov;111(3):655-74
3932127
Theor Popul Biol. 1983 Apr;23(2):202-15
6612632
Curr Biol. 2002 Jun 25;12(12):1040-5
12123580
Genetics. 2000 Nov;156(3):1437-48
11063715
Proc Natl Acad Sci U S A. 2004 Jun 1;101(22):8396-401
15159545
Science. 2007 Aug 10;317(5839):813-5
17690297
Genetics. 2004 Aug;167(4):2045-53
15342539
Genetica. 1998;102-103(1-6):127-44
9720276
Proc Natl Acad Sci U S A. 2001 Jan 30;98(3):1113-7
11158603
Genetics. 2007 Jun;176(2):1013-22
17409090
J Theor Biol. 2006 Nov 7;243(1):114-20
16859714
Genetics. 2000 Dec;156(4):2093-107
11102398
Evolution. 2002 Jul;56(7):1317-30
12206234
Genetics. 2006 Feb;172(2):751-7
16299384
Genetics. 2007 Aug;176(4):2441-9
17565958
J Theor Biol. 2006 Jan 21;238(2):279-85
15990119