Growth-related intraclonal genetic changes in Gracilaria chilensis (Gracilariales : Rhodophyta)

Gracilaria ia chilensis exhibits noticeable intraclonal variation, some of which is presumed to result from mitotic recombinations or other types of D NA turnover associated with replication activities during cellular division . To test this, genetic variability (determined by multilocus fingerprintin g markers using the randomly amplified polymorphic DNA technique, RAPD) and total growth were simultaneously measured over time in clonal replicates o f G. chilensis incubated under controlled laboratory conditions. The result s suggest that genetic variability increases as growth occurs and biomass a ccumulates, supporting the hypothesis of growth-related increases in geneti c heterogeneity. For species massively propagated by thallus fragmentation in either naturally or farmed populations, growth-dependent genetic changes may constitute a powerful means of generating intra-population variation w ithout thalli becoming reproductively mature, and, as a, consequence, bypas sing meiosis and/or sexual recombination.