Oreaster reticulatus is a large, thick sea star commonly found in the tropical western Atlantic Ocean . Adults range in diameter from 16-20 cm and have been reported to have numerous, distinct morphologies with respect to background and spine color patterns (Buchsbaum et al., 1987). Humann (1992) reported that different developmental stages have distinct colors. For example, juveniles tend to be green. O. reticulatus have separate sexes and reproduce by synchronously shedding their gametes into the water (Buchsbaum et al., 1987). Therefore, distinct color morphs could be the result of having (1) a single, polymorphic species as currently reported in the literature; (2) two or more distinct species or (3) interspecific hybridization.
This study focuses on individuals collected from Graham’s Harbor on the island of San Salvador , Bahamas in March of 2004. For each sampling, the site was actively searched for forty minutes, each collected individual was measured across the disk, and the colors of the background and spines were recorded. In addition, a few tube feet were removed, DNA was isolated and Amplified Fragment Length Polymorphism (AFLP) analysis was conducted.
AFLP analysis is a PCR (Polymerase Chain Recreation) based technique that allows us to compare selectively amplified fragments of DNA. The DNA fragment banding pattern is visualized by agarose gel electrophoresis and different banding patterns can indicate unique genetic differences. AFLP analysis was run to determine if monomorphic markers existed between the different color morphs. This research represents the first step in our attempt to differentiate between our three different hypotheses.
Erin Lynch, ’04 Madison , WI
Majors: Biology and Spanish
Sponsor: Craig Tepper