CAUSES AND IMPLICATIONS OF INTRA-CLONAL VARIATION IN GRACILARIA-CHILENSIS (RHODOPHYTA)

Strain selection studies in Gracilaria chilensis detected significant levels of intra-clonal variation. These findings motivated more detail ed studies on the causes and implications of intra-clonal variation in these and other red algal species. Our results indicate that intra-cl onal variation is common among replicated units (e.g.: carpospores and ramets) of several red algal species and suggest that a larger data b ase probably will show the occurrence of various kinds of intra-clonal changes, differing in frequency of occurrence and magnitude of phenot ypic expression. It is likely also that different species would exhibi t different amounts of variation. Four types of factors may cause intr a-clonal variation: (1) physiological or developmental differences amo ng ramets, (2) localized pathogen infections, (3) several kinds of gen etic changes, and (4) sporeling coalescence. Intra-clonal variation am ong ramets: (1) increases the possibility of genet survival, (2) expla ins the origin of morphological and physiological differences among ra mets of a given genet, (3) explains the large population variation fou nd in many clonal species and (4) suggests that strain selection of so me economically important seaweeds should be thought of as a fairly co ntinuous process due to the instability of some of these clones.