Subunit compositions of crustacean haemocyanins are species-specific: evidence from non-decapod species

Electrophoretic examination of dissociated haemocyanin subunits from a numb er of amphipod, decapod and isopod crustaceans supports the hypothesis that subunit composition is species-specific, despite marked within-species var iation in many species. General patterns of heterogeneity on native PAGE ge ls were also evident between groupings within the Amphipoda. Gammarid amphi pods could be split into two groups; one characterised by a high degree of heterogeneity and the other by a tow degree of heterogeneity. The talitrid amphipods generally displayed a low degree of heterogeneity similar to, alt hough still distinct from, the second gammarid category. Haemocyanin from t he Hyalidae, a family allied to the talitrids was highly heterogeneous, sim ilar to the first gammarid group and unlike the talitrids. Isopod haemocyan in banding patterns were more similar to one another than to any of the amp hipod or decapod species examined. In general, the molecular weights of the amphipod Hcs tended to be greater than those of the isopods, with the deca pods being lowest of all. It is suggested that He subunit heterogeneity may be a useful tool for investigating speciation and speciation events, and f or reliably separating very closely-related species (e.g. Gammarus spp.), p urely on the basis of their Hc subunit compositions. (C) 2001 Elsevier Scie nce Inc. All rights reserved.