Assessment of populations of Gracilaria chilensis (Gracilariales, Rhodophyta) utilizing RAPDs
Abstract
Phenotypic variability and mixing of material due to massive cultivation for commercial purposes has contributed to the taxonomic confusion of Gracilaria in Chile. At least four species with cylindrical thalli and similar morphology have been recorded. However, since establishment of G. chilensis, most of the collected thalli have been attributed to this species despite the lack of diagnostic features. In an attempt to resolve whether Gracilaria from 3 localities where it grows in natural and artificial populations belongs to the same species, gametophytic samples were compared by applying RAPD-PCR to their total DNA. This was analysed using 25 different 10-mer primers from which 21 revealed polymorphism within and between populations. Similarity matrices and cluster analyses were performed based on the presence/absence of bands representing fragments of DNA generated by random amplification. Similarity values between two of the populations were equivalent to those detected within a third, indicating the mixing of genetic material due to transplant between the two former localities. Similarities between samples of Chilean Gracilaria and G. tenuistipitata from Sweden are considerably lower (0.45-0.53) than those between populations from Chile (0.74-0.88), confirming the existence of a single specific taxon, G. chilensis, in these three localities.
Description
Keywords
Gracilaria chilensis, Algal DNA variability, RAPD fingerprinting, morphological variability