POPULATION GENETICS OF MARINE SPECIES OF THE PHYLUM ECTOPROCTA

¹ Department of Biology, Juniata College, Huntingdon, Pennsylvania 16652
² Department of the Geophysical Sciences, University of Chicago, Chicago, Illinois 60637

Proteins of marine species of the Phylum Ectoprocta can be easily separated by zone electrophoresis on polyacrylamide gels. Many bands revealed by electrophoresis represent the product of individual genetic loci from which gene and genotype frequencies were calculated. Results are reported for 19 loci which are responsible for the formation of esterases, malate dehydrogenase and "leucine" aminopeptidase in Schizoporella unicornis and Bugula stolonifera.

Observed genotype frequencies correspond closely with those predicted by Hardy-Weinberg equilibria indicating that these marine ectoprocts are dominantly outbreeding and that panmictic local populations cover an area of square meters. In addition, 25.0-54.5% of the diagnosed loci are polymorphic, depending on the species. Forty-two % of all loci identified are polymorphic.

The most important implication of these findings is that the population structure and amount of genetic variability in ectoprocts (and by implication in other marine organisms) is fundamentally similar to that of terrestrial organisms. If these tentative conclusions are substantiated by subsequent work, the processes of speciation in marine organisms may differ little from those proposed in the better documented research on terrestrial animals.

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