Rates of Spontaneous Mutation

[iatsu.pavu.com]

Appendix I - Frequency of Mutations

When we speak of the frequency of mutations we have to distinguish between
the mutation rate for the entire genome and the mutation rate for the
effective genome (the 5% that is not junk DNA). In Genetics 148:1667-1686,
April 1998) John W. Drake et al estimate that the average human zygote has
about 64 mutations, most of which occur in "junk" DNA.

>From tables 4 and 5 in "Rates of Spontaneous Mutation", by JW Drake et al,
Genetics 148:1667-1686 (April, 1998):

Organism     effective genome size (Ge)     mutations/Ge/replication
bacteriophage M13     6.4 * 10^3     0.0046
bacteriophage lambda     4.9 * 10^4     0.0038
bacteriophages T2 & T4     1.7 * 10^5     0.0040
E. coli     4.6 * 10^6     0.0025
Saccharomyces cerevisiae     1.2 * 10^7     0.0027
Neurospora crassa     4.2 * 10^7     0.0030
C. elegans     1.8 * 10^7     0.004
Drosophila     1.6 * 10^7     0.005
Mouse     8.0 * 10^7     0.014
Human     8.0 * 10^7     0.004

Note that for humans, the number of cell divisions prior to sperm formation
in a male of age 30 is about 400. This works out to about 1.6 mutations per
sperm cell. Drake assumed that almost all mutations were in the sperm; this
assumption does not appear to be correct. See note 10 for further
discussion. 

In the 28 January 1999 issue of Nature, in the article "High genomic
deleterious mutation rates in hominids" Walker and Kneightey estimate that
the mutation rate in the effective genome is a bit higher, 4.2 mutations per
individual, of which 1.6 are deleterious. See note 7 for further discussion.