Mitochondrial (mt) DNA population structure was examined by using restriction fragment length polymorphism analysis (RFLP) among 149 white mouth croakers (Micropogonias furnieri) sampled from six locations in the Brazilian coast. Heterogeneity tests revealed no differentiation in mtDNA haplotype frequencies within the region between 23°S and 34°S (P=0.263), but significant heterogeneity was detected between north and south of 23°S (P<0.003). Analysis of molecular variance (AMOVA) indicated a low F ST value (0.008, P=0.180) among south-central localities (23-34°S), but a significant level of population subdivision (F ST = 0.322, P< 0.003) between north and south-central localities. UPGMA analysis of mtDNA sequence divergence revealed differentiation between white mouth croakers collected from north and south of 23°S. Mantel test found significant association between matrices of genetic distance and geographic distance among samples. Collectively, these data were consistent with a single genetic stock of Micropogonias furnieri in the Brazilian coast, with semi-isolated populations occurring in the north and south of 23° S.
Genetic population structure; mitochondrial DNA; RFLP; Micropogonias furnieri
