RESUMO
Callinectes sapidus Rathbun, 1896 is a western Atlantic species with a disjointed natural geographic range from Massachusetts, USA to Venezuela (distribution area 1) and from Alagoas, Brazil to northern Argentina (distribution area 2). It is the only species of portunid crab commercially harvested in the continental United States but is also imported into the US from several Latin American countries, Venezuela and Mexico in particular. In the United States, crab products labeled as "blue crab" and "Product of the USA" may not legally contain other species of crab or C. sapidus not harvested in the United States. The present study documents nucleotide variation within the barcode region of cytochrome c oxidase I (COI) in 417 reference specimens of C. sapidus collected from throughout its natural range. The goal of this study is to determine if this variation can be utilized to detect mislabeled C. sapidus products sold in interstate commerce by comparing genetic signatures in reference specimens to those observed in commercial crabmeat labeled as "Product of the USA" and "Product of Venezuela." In reference specimens, we observed high levels of genetic variation in the barcode region. However, three lineages were consistently observed with significant pairwise F st values between the lineages. Lineage 1 was observed throughout the natural geographic range but predominated in the continental US and was the only lineage observed in the major crabmeat-producing states (MD, LA, VA, NC). Lineage 2 primarily occurred in the Caribbean region of distribution area 1 but was also infrequently encountered in the South Atlantic Bight region of the US coast. Finally, Lineage 3 was only observed in Brazilian waters and had the lowest haplotype and nucleotide diversity values. Lineages 1 and 2 were separated by a mean pairwise distance (p-distance) of 3.15%, whereas Lineage 3 had a mean p-distance of 2.55% and 1.35% to Lineages 1 and 2, respectively. Within lineage mean p-distances were 0.45%, 0.19%, and 0.07% for Lineages 1, 2, and 3, respectively. Among all vouchered reference specimens collected from the continental United States, Mexico, Puerto Rico, and Venezuela, we identified 22 phylogenetically informative sites that drive observed lineage divergences. Haplotypes identified from barcode COI sequences from commercial C. sapidus products labeled as originating from the US all aligned with haplotypes from Lineage 1 reference specimens and haplotypes from commercial products labeled as originating from Venezuela all aligned with Lineage 2, suggesting that these lineages may be useful for indicating whether products originate from the continental US or are imported when package labeling is in question.
RESUMO
Wildlife forensics has recently been recognized among the wide variety of forensic science disciplines. This review compares human and wildlife DNA forensics, which use the same genetic tools, but often for far different purposes. Human forensic genetics almost invariably attempts to identify individual perpetrators involved in a given crime. Wildlife forensics often determines whether a crime has occurred. In addition to techniques familiar in human laboratories, like individual matching with STRs, wildlife analysts may be asked to determine the taxonomic identity, geographic source, or sex of evidence items, or the familial relationships or minimum number of individuals among a group of samples. This review highlights the common questions, legal framework, databases, and similar validation requirements to foster understanding between disciplines. Based on this understanding, human and wildlife DNA practitioners may work together and learn from each other in order to elevate the discipline of forensic genetics.
