Figure 3. Mean frequencies of freshwater alleles at marker SNPs within identified DIs, at freshwater populations of different ages.

(A) Natural populations. The horizontal axis shows the approximate ages of populations, ranging (left to right) from two marine populations (∼0 years) to recent (∼34 and ∼250 years) and older lake populations (∼600 and ∼700 years). Whiskers, standard deviation. (B) Experimental populations. For each of the DIs of marker SNPs, the assumed initial 50% frequency of freshwater alleles (black line) and their current frequencies are shown for two experimental populations: quarries Malysh (left) and Goluboy (right), each started in 1978. Dashes, boxes and whiskers correspond to the median, standard deviation, and 5^th and 95^th percentiles, respectively. Red, DIs identified under the strong criterion; blue, DIs identified under the weak criterion.