Revista Chilena de Historia Natural 79 (4): 423-434, 2006
RESEARCH ARTICLE
Genetic variability and population structure in tunicate Pyura chilensis Molina,
1782, in the coast of Chile
The ascidian Pyura chilensis is an ecologically important species due to its
aggregates, providing habitat for other species. In addition, it is an economically important species being commercially exploited along
the coast of Chile. Here, changes in distribution and abundance have been observed during the last decade that have been linked to
overfishing. Patterns of genetic variation and population structure are important to understand biodiversity, management and
conservation of species. Thus, the main objective of this study was to determine the genetic variability and population structure of
Pyura chilensis in three localities along the Chilean coast (Antofagasta, Talcahuano, Puerto Montt). The polymorphic loci
obtained were: Mdh-1 and Gpi-1 for P. chilensis. The Fst values showed slight population structure (Fst
= 0.019), and the genetic differentiation showed statistically significant values (P = 0.031). The Puerto Montt locality was
significantly different from the other two sites in the pairwise comparison in some loci. The genetic differentiation among localities of
P. chilensis could be explained by a combination of different causes: (i) low larval dispersion capacity associated to the
larval life time of this species (12 to 24 h), and (ii) differences in oceanographic conditions between localities and a closed circulation
pattern that restrict dispersion. We conclude that monitoring of genetic diversity levels are essential to establish conservation and
management plans of exploited marine resources.
Key words:
genetic variability,
population genetics, allozymes, Pyura chilensis, Chile
