Population genetics and historical demographic inferences of the blue crabCallinectes sapidusin the US based on microsatellites

Abstract

The native range of the blue crab Callinectes sapidus spans Nova Scotia to northern Argentina. In the US, it constitutes a keystone species in estuarine habitats of the Atlantic coast and Gulf of Mexico (GOM), serving as both predator and prey to other species, and also has historically represented a multi-billion dollar fishery. Knowledge relevant to effective management and monitoring of this ecologically and economically important species, such as levels of population genetic differentiation and genetic diversity, is necessary. Although several population genetics studies have attempted to address these questions in one or more parts of its distribution, conflicting results and potential problems with the markers used, as well as other issues, have obscured our understanding on them. In this study, we examined large-scale genetic connectivity of the blue crab in the US, using 16 microsatellites, and genotyped individuals from Chesapeake Bay, in the US Atlantic, and from nine localities along the US GOM coast. Consistent with the high long-distance dispersal potential of this species, very low levels of genetic differentiation were detected for the blue crab among the ten US localities examined, suggesting it constitutes a large panmictic population within this region. Estimations of genetic diversity for the blue crab appear to be high in the US, and provide a baseline for monitoring temporal changes in this species. Demographic analyses indicate a recent range expansion of the US population, probably during the Holocene. In addition, capitalizing on published microsatellite data from southern Brazil, our analyses detected high genetic differentiation between localities in the US and Brazil. These results point to the need for examination of genetic diversity and differentiation along the area spanning the US to southern Brazil.

Interaction analysis of Mycobacterium tuberculosis between host environment and highly mutated genes from population genetic structure comparison

“…Population genetic structure comparison is the main method used to determine whether two populations evolve independently or have gene exchange [29,30]. Because M. tb is a highly conserved and differentiated species, the molecular structure differences of its mutant subgroups are relatively small.…”

Interaction analysis of Mycobacterium tuberculosis between host environment and highly mutated genes from population genetic structure comparison

“…Population genetic structure comparison is the main method used to determine whether two populations evolve independently or have gene exchange [28,29]. Because M. tb is a highly conserved and differentiated species, the molecular structure differences of its mutant subgroups are relatively small.…”

A Synthesis of Deepwater Horizon Impacts on Coastal and Nearshore Living Marine Resources

“…Blue Crab -Populations in the U.S. GoM have been separated into two population units (east and west of Cape San Blas; Figure 1) for the purposes of stock assessment and management (VanderKooy, 2013). However, recent analysis based on microsatellite data reveal high levels of gene flow throughout the northern GoM, potentially indicating a single panmictic population (Macedo et al, 2019). Like the Eastern Oyster, Blue Crabs in the GoM have an extended spawning period and complex early life history.…”

“…Females mate once in their lifetime in the upper estuary, then migrate to coastal waters where they may spawn repeatedly throughout their lives. Mating occurs when estuarine temperatures exceed about 22 • C (e.g., in spring) in the upper estuaries but fertilized eggs are released into coastal waters, thus subjecting the various larval stages to potentially wide dispersal during their 31-49 day larval development period, which provides justification to explain the lack of genetic population differentiation (Macedo et al, 2019). Overall commercial landings of Blue Crab in the U.S. GoM have remained relatively stable since about 1990, however, in some states (Alabama, Florida and Texas) landings have declined since the late 1990s (Supplementary Figure 2).…”