Fig. 3From: Multiple origins of melanism in two species of North American tree squirrel (Sciurus)Median joining MC1R haplotype network for the gray squirrel and fox squirrel. Each circle represents an allele and each line represents one or more substitutions or a deletion. Alleles from fox squirrel are blue, alleles from gray squirrel are red. Area of circles is proportional to the numbers of alleles sampledBack to article page