Regional variation in electromorph frequencies in the tuatua, Paphies subtriangulata, around New Zealand

Abstract

Four polymorphic enzyme loci were tested in 13 samples of tuatua, Paphies subtriangulata, from around New Zealand. Statistical analyses of the distribution of electromorphs indicate 3 geographical groups: north, central, and Chatham Islands. One sample from Stewart Island may represent a fourth southern group owing to its geographical isolation and genetic differences with the central group. It is suggested that the genetic differentiation is maintained by current movements which restrict gene flow between regions. Samples from the Chatham Islands showed lower hetero‐zygosities than mainland samples. This offshore island group is beyond the normal limits of larval dispersal from mainland populations.

Key words:

• tuatua
• Paphies subtriangulata
• electromorph
• electrophoresis
• heterozygosity
• Chatham Islands