PURCELL, Catherine; EDMANDS, Suzanne; University of Southern California; University of Southern California: Microsatellite and MtDNA D-Loop Analysis of Population Structure in Striped Marlin, Tetrapturus audax.

In this study, we are examining population genetic structure in a highly migratory species, striped marlin (Tetrapturus audax). Due to structuring already seen in this organism, they can be used to address important questions such as: (1) Will different loci show the same genetic pattern previously found? (2) Is the genetic structure temporally stable? (3) What is the underlying mechanism creating this population divergence? We are examining the population subdivision using both mitochondrial and nuclear DNA markers. PCR is used to amplify the mitochondrial control region, which is then sequenced to detect changes at the nucleotide level, and can be used to infer evolutionary history among populations. Nuclear microsatellites are used as independent measures of heterogeneity within and among populations. Because mitochondrial DNA is maternally inherited and microsatellites are biparentally inherited, comparisons between these two markers may help determine whether the population genetic structure is sex-specific. We are using a concurrent sampling scheme to collect adult tissue from 6 locations representative of their range in the Pacific: Mexico, Ecuador, Southern California, Hawaii, Japan, and Australia. This repeat sampling will be conducted over the course of 3 years to test for temporal stability among locations. We will present the goals of this project, our efforts to date, and a summary of our preliminary data.