A multi-locus genetic assignment technique to assess sources of Agaricia agaricites larvae on coral reefs

Assignment of individuals to populations based upon genetic data is an important ecological problem that requires many polymorphic markers, often more than are available using single locus techniques. To demonstrate the utility of amplified fragment length polymorphisms (AFLP) in studying larval dispersal and recruitment in coral populations, two sets of AFLP primers were used to genotype colonies of the coral Agaricia agarticites Linnaeus from three widely separated geographic locations: the Bahamas (23 degrees 28'N, 75 degrees 42'W) and Key Largo, Florida (24 degrees 55'N, 80 degrees 31'W-two sites separated by 12 km) in 1995, and the Flower Garden Banks (FGB) in the Gulf of Mexico (27 degrees 55'N,93 degrees 36'W) in 1997. In addition to adult samples from each site, recruits were collected from settling plates placed on the East FGB for I year (1997-1998). The AFLP technique yielded 45 polymorphic markers. An analysis of molecular variance (AMOVA) showed significant genetic differences among the four adult populations, even between the two Key Largo sites. The recruits were significantly different from all adult populations except those from the FGB. Discriminant function analysis and the program AFLPOP were used to assign individuals to populations. Using the adult AFLP-banding patterns to build the statistical models, both procedures correctly assigned the majority of adults to their respective populations in simulations and assigned all but one of the recruits to the Flower Garden population from where they were collected. The AFLP technique provides a simple and adaptable population assignment method for studying recruitment processes in A. agaricites and other coral, species.