Abstract
Genetic variation at five enzyme loci was determined for over 1000 individuals of Enteromorpha linza (L.) J. Ag. from four localities in Long Island Sound and one locality on the Atlantic coast of Long Island. All samples which were sufficiently polymorphic at one or more loci showed patterns of genetic variation significantly different from that expected for populations with predominantly sexual reproduction. Non-random association among the five loci resulted in a distribution of multilocus phenotypes that deviated significantly from the pattern expected for sexual reproduction. This evidence for predominantly asexual reproduction occurring in the field was supported by laboratory culture experiments. Twenty-one isolated individuals released spores which grew into new plants. For the loci tested, the phenotypes of all 259 second generation plants were identical to the parent plant with no segregation observed for heterozygous phenotypes. These results demonstrate the usefulness of electrophoret...