Allozyme variation in Busycon whelks (Gastropoda: Melongenidae)

Large Busycon whelks are used in physiological research and are key predators in shallow water marine communities in eastern North America. Allozyme analysis of 16 loci in Busycon carica (knobbed whelk), B. sinistrum (left-handed or lightning whelk), and the closely related outgroup Busycotypus spiratum (pear whelk) was performed. Striking differences in within-species genetic differentiation were observed. Geographic variation in B. carica is moderate (F(ST) = 0.051). In B. sinistrum, however, F(ST) is 0.625, suggesting the existence of either highly distinct subspecies or unresolved species. The pattern of genetic variation in B. sinistrum may be congruent with that in other taxa that have experienced Gulf-Atlantic and eastern-western Gulf vicariance events. The data are compatible with an evolutionary rate of 0.046 Nei D/million years.