ABSTRACT
Detecting multiple paternity in wild populations of the broad-snouted caiman (Caiman latirostris) has important implications for conservation efforts. We have applied microsatellite markers to examine genetic variation in C. latirostris and also have provided the first data concerning detection of multiple paternity in wild populations of this species. Blood samples from four nest-guarding C. latirostris females and their hatchlings were obtained from Santa Fe Province, Argentina. Amplified products were analyzed by electrophoresis on 10% polyacrylamide gels and visualized with silver staining. Four out of the eight markers tested reliably amplified and yielded useful data. Using polyacrylamide gels with silver staining provides high enough resolution to obtain individual genotypes. In order to assess the presence or absence of more than two parents in each nest, we used the single locus Minimum Method, and applied Cervus 3.0 and Gerud 2.0 software in parentage analyses. Our results indicate more than one father in at least two families. This behavior could be the consequence of high habitat variability in the area where our population was sampled. The ability to understand mating systems is important for maintaining viable populations of exploited taxa like C. latirostris.
Subject(s)
Alligators and Crocodiles/genetics , Microsatellite Repeats/genetics , Animals , Argentina , Female , Genetics, Population , Male , ReproductionABSTRACT
Broad-snouted caiman's (Caiman latirostris) geographic distribution comprises one of the widest latitudinal ranges among all crocodilians. In this study we analyzed the relationship between geographic distance (along the species latitudinal range) and genetic differentiation using DNA microsatellite loci developed for C. latirostris and Alligator mississippiensis. The results suggest that there is a consistent relationship between geographic distance and genetic differentiation; however, other biogeographical factors seem to be relevant. The Atlantic Chain (Serra do Mar) seems to be an effective geographic barrier, as well as the relatively narrow (< or =1.5 km) sea channel between Cardoso Island and the continent. In addition, coastal populations seem to have been well connected in recent geological time (Pleistocene 16,000 years ago) all along the eastern Brazilian coast. Further studies should focus on the São Francisco River drainage, which is still poorly known for this species.
