GENETIC-STRUCTURE AND MODE OF REPRODUCTION IN 5 SPECIES OF SEA STARS (ECHINODERMATA, ASTEROIDEA) FROM THE ALASKAN COAST

Genetic structure was studied in five sea star species with diverse patterns of reproduction. Eleven sea star samples from six locations in Alaska. representing five species and three genera in the family Asteriidae, were analyzed for allozyme variation at 16-25 loci. Levels of intra- and inter-population variation were determined for three brooding species (Leptasterias hexactis, Leptasterias epichlora, and Leptasterias polaris) and two free-spawning species with long planktonic larval periods (Evasterias troschelii and Pisaster ochraceus). Population divergence of L. epichlora (F(ST) = 0. 156) was much higher than that of P. ochraceus (F(ST) = 0.006) or E. troschelii (F(ST) = 0.023). Earlier work in our laboratory found that L. hexactis also showed significant interpopulation differences in allele frequencies. Expected heterozygosity was 0.050 in E. troschelii, 0.083 in L. polaris, 0.092 in P. ochraceus, 0. 135 in L. epichlora, and 0. 151 in L. hexactis, and was unrelated to mode of reproduction.