Revista Chilena de Historia Natural 77 (3): 559-567, 2004
RESEARCH ARTICLE
Morphological and genetic differentiation among Chilean populations of Bufo spinulosus
(Anura: Bufonidae)
Bufo spinulosus has a wide and fragmented distribution range in Chile (18°
to 33° S) along altitudinal and latitudinal gradients. Genetic variation was estimated using RAPD (Random Amplified Polymorphic DNA)
markers in 10 populations from northern and central Chile. Morphometric and genetic information was analyzed as a function of
geographical origin. The correlation between genetic and morphometric differentiation was analyzed by the Mantel test. An increase in
body size as a function of latitude was observed. Specimens from El Tatio had the smallest body size and the greatest morphometric
divergence. The AMOVA applied to genetic data indicated that 57.85 % of the variance is explained by interregional differences and that
30.12 % of the variance is found within populations. Low levels of within-regions genetic differentiation was observed in northern
populations while higher levels of genetic differentiation was found in populations from central Chile. Mantel tests revealed a significant,
positive correlation between genetic variation and geographic distance. When we excluded El Tatio population, Mantel test analyses
showed significant correlations between morphological distance and genetic and geographic distances. We discuss whether water
temperature could explain the morphological divergence observed in individuals from El Tatio.
Key words:
amphibians,
geographic variation, morphometry, RAPDs, AMOVA
