The equation in the sentence "Under a neutral model of evolution, sa0 is one randomly selected sequence, and E[d(sa0,s1)]  = E[d(s0x, s0y)] where the right-hand term..." (p. 10490, right column, second paragraph) should be E[d(sa0,s0)]  = E[d(s0x, s0y)].

We are grateful to Anders Kvist of Lund University for bringing this error to our attention.

jl 15Feb07