Some studies, however, demonstrate that the bifurcation of the south equatorial current is not an effective barrier to dispersal for many CPI-613 Dehydrogenase inhibitor marine taxa, furthermore, the main currents parallel to the Brazilian coast show slight seasonal changes in direction that could allow some connectivity between the locations analyzed. Thus, all of these features are consistent with high genetic similarity along the Brazilian coast, as demonstrated in this study, and they may be the main factors regulating the genetic connectivity between the Brazilian populations of O. chrysurus, as observed in another lutjanid, L. purpureus. The results of the present analysis revealed high levels of genetic variation in the investigated yellowtail snapper populations, especially in the mitochondrial markers, which presented a large number of haplotypes, similar to that recorded for L. purpureus and L. campechanus, with similar genetic variability demonstrated between localities, over a distance of approximately 3,000 km along the Brazilian coast. This outcome would be expected for populations linked by intense gene flow, a scenario commonly observed in a number of marine species. The high indices of genetic WZ8040 company diversity recorded in the present study, especially for the mitochondrial markers, and particularly the Control Region, are a common feature of marine teleosts, including lutjanids, and have been recorded previously in O. chrysurus. This high genetic variability cannot be interpreted as an absence of an impact of fishing on these populations because the commercial exploitation of this species is relatively recent. Examples from the literature reveal several situations where overfishing apparently shows no direct relationship with genetic diversity indices. For example, Hoarau et al. did not report decreased levels of genetic variability in microsatellite markers in a temporal analysis of Pleuronectes platissa covering almost 100 years, even though this species has been heavily exploited since the XIX century. Additionally, Pinsky & Palumbi recently performed a meta-analysis involving hundreds of fish species and observed high levels of genetic diversity for snappers of the genus Lutjanus, even for species that are considered to be overfished. Distinct levels of genetic diversity were observed at the three nuclear loci analyzed in the present study. The most variable nuclear locus was the intron of the IGF 2 gene, which presented a degree of polymorphism comparable to that observed in the mitochondrial Control Region, indicating that it is a potentially useful marker for population-level and phylogeographic studies in lutjanids, as observed for Centropomus. The yellowtail snapper inhabits coastal waters and is therefore relatively susceptible to sea level oscillations. During the last glacial maximum, for example, approximately 90% of the present-day continental shelf of the Caribbean region was above sea level, due to a decrease in the sea level of 120 meters.