GENETIC-VARIABILITY WITHIN A POPULATION AND BETWEEN DIPLOID HAPLOID TISSUE OF MACROCYSTIS-PYRIFERA (PHAEOPHYCEAE)/

Multi-locus DNA fingerprints using an M13 pro be were obtained for eig ht individuals of giant kelp Macrocystis pyrifera (L.) C. Ag. collecte d from Monterey Bay, California. For each individual, DNA was extracte d from a diploid blade and from ca. 10(9) haploid spores that were rel eased from four to five sporophylls. Viable or swimming spores from on e individual were pooled and referred to as a spore group. A total of 34 bands (4-19 kb) was detected in DNA fingerprints from the eight bla des and eight spore groups, with individual blade or spore groups exhi biting 7-18 bands (mean = 12. G). One band (4.5 kb) was present in all 16 samples. Eight bands were detected in 11-14 of the 16 samples. Sim ilarity, indices were calculated for all pairwise comparisons of finge rprint bands among all possible combinations of blades and spore group s. Mean similarity indices for the eight blades (0.51, SE = 0.032) and spore groups (0.56, SE = 0.031) were significantly lower than for the eight comparisons of the blade and spore groups from a single individ ual (0.86, SE = 0.052). The data indicate that DNA fingerprints can be used to measure genetic variation within populations of M. pyrifera b ecause variation of DNA fingerprints associated with meiotic products (spores) of a given individuals is small relative to variation observe d among individuals within the population. Additionally, fingerprint v ariation between diploid vegetative tissue and haploid meiotic product s may be a measure of genetic change due to recombination or DNA turno ver mechanisms.