King & Wilson (1975) on the genetic similarity between Humans & Chimps
M-C King & AC Wilson (1975)
used Protein Electrophoresis to compare genetic
variation at n = 88 alleles from 42 loci
between Humans (Homo sapiens) and Chimps (Pan
troglodytes). Their Table 2 data are
summarized here. For each
allele, si is the product of the
frequencies of each allele in the two species, and for each
locus, Si is the sum of si
for its alleles. Thus, for the three alleles
at locus AP, Si
= (0.29)(0.0) + (0.68)(1.00) + (0.03)(0.0) =
0.68. Si estimates the similarity
at each locus between species, that is, the
probability that alleles drawn at random will be identical.
A majority of loci are either fixed (n = 17) for alternative alleles, or identical (n = 13) for the same allele, in the two species. This simplifies calculation of the average genetic similarity (
) across
loci, because Si = 1 or 0,
respectively, for each locus in these two classes. For
variable loci, the contribution is the product of the number
of loci and the average value across loci. Then, = [(17 x
0) + (13 x 1) + (12 x 0.708)] / 42 = 0.512.
If
estimates similarity, then D = (1 - )
estimates Distance. The accuracy of the Distance
estimate can be improved by applying the Poisson
Correction for multiple hits. For
electrophoretic data, the correction is D' = -ln().
A majority of loci are either fixed (n = 17) for alternative alleles, or identical (n = 13) for the same allele, in the two species. This simplifies calculation of the average genetic similarity (
) across
loci, because Si = 1 or 0,
respectively, for each locus in these two classes. For
variable loci, the contribution is the product of the number
of loci and the average value across loci. Then, = [(17 x
0) + (13 x 1) + (12 x 0.708)] / 42 = 0.512.If
estimates similarity, then D = (1 - )
estimates Distance. The accuracy of the Distance
estimate can be improved by applying the Poisson
Correction for multiple hits. For
electrophoretic data, the correction is D' = -ln().Data arrangement & Text material © 2024 by Steven M. Carr