Does Speciation between Arabidopsis halleri and Arabidopsis lyrata Coincide with Major Changes in a Molecular Target of Adaptation?
Figure 2
Distributions of derived synonymous SNP frequencies in A. halleri and A. lyrata calculated using A. thaliana as an outgroup.
Exclusive polymorphic sites (bottom row and first column) are defined as positions where the derived allele frequency is between >0 and <1 in one species, but has a frequency of zero in the other species. Fixed differences are positions where the derived allele frequency is = 0 in one species and = 1 in the other species. Shared polymorphic sites are positions where the derived frequencies are >0 and <1 in both species. Putatively ancestral polymorphic sites are positions where the derived allele frequency is = 1 in one species and between zero and unity in the other species.