Allozymic similarities among species of partula on moorea

Abstract

Variation in allozymes at 23 loci was examined in 62 populations, representing the seven species of land snails of the genus Partula inhabiting the island of Moorea in French Polynesia. All but four of the 23 loci are polymorphic in at least one species, and the average heterozygosity per individual is 0.13. In contrast to their high variability within species, the allozymes show relatively little divergence between species. Coefficients of genetic identity between populations from different species range from 0.73 to 0.99, with an average of 0.89. Coefficients of identity between conspecific populations average 0.94, and range from 0.77 to 1.00. Within each of the two “species complexes”, the mean coefficient of identity between species that hybridise is the same as that between non-hybridising species, suggesting that allozymic variation and reproductive isolation are independent of each other. The rate of divergence on Moorea is apparently consistent with the rate that has been calculated for the Society Islands as a whole (a change in Nei’s D of approximately 0.13 per million years). The high levels of similarity between species appear to be consequences of their recent origins. Some populations of Partula taeniata in southern Moorea differ from other populations of their own species to an extent greater than any interspecific differences elsewhere on the island, emphasising the lack of necessary correlation between allozymic change, morphological divergence, and reproductive isolation. © The Genetical Society of Great Britain.