Relações genéticas em espécies de camarões peneídeos (Crustacea, Decapoda, Penaeidae) de ocorrência no litoral brasileiro

Abstract

Penaeidae family occurs in all oceans, particularly in tropical regions and represents an important global fishing resource. In Brazil, penaeid species have been shown decline, of their populations, which are considered overexploited. Therefore, a greater knowledge about these species is required for the developing of appropriate conservation actions. However, genetic studies of penaeids, including phylogeography, geographic distribution and phylogeny, are still scarce. In the present work, genetic structure and genetic relationships were characterized for different marine shrimp species belonging to the Penaeidae family, with special emphasis on those of occurrence in the Brazilian coast (Xiphopenaeus kroyeri, Farfantepenaeus paulensis, Farfantepenaeus subtilis and Farfantepenaeus brasiliensis). Mitochondrial and nuclear markers were used in order to clarify aspects related to the geographic distribution and genetic relationships among the studied penaeid species and the implications for conservationist approaches. Specific oligonucleotides were designed to amplify four mtDNA regions (COI, 16S, Cytb and DLoop). The results showed efficient patterns for 16 native species of Brazilian and Mozambican coasts. Numts presence and its implication for penaeid genetics were investigated using specific and universal primers for COI gene. Pseudogenes were detected for some penaeid species. Cytb pseudogene for the Penaeidae family was reported by the first time. DNA barcoding approach was tested in several species from Brazilian coast. The barcoding analysis evidenced a high range of intraspecific distance, suggesting the necessity of taxonomic review into Penaeidae. The existence of species complex was investigated for both X. kroyeri and F. subtilis. Phylogeographical signs and population structure were no observed for F. subtilis along the Brazilian coast. F. paulensis populations, collected in Lagoa dos Patos (RS) and Cananéia (SP), showed genetic structuring by analyzing of COI gene. That data can be reflecting the existence of differentiated-genetically adult stocks or ancient structure. Two recent population expansions, one of them before and the other one after the last period of the maximum glacial, were observed for F. paulensis. mtDNA and RAD-seq data were using to study the species X. kroyeri populations. The mtDNA analysis suggested that the upwelling from Cabo Frio (RJ) consists in a semipermeable barrier to X. kroyeri species, limiting the genetic flow between populations from North and South of Cabo Frio for. The analysis of approximately three thousand SNPs revealed three different genetic stocks, possibly related to the hydrodynamic characteristics of the sampled geographic regions, which may be holding different larvae pools. The study herein brings important information about genetic relationships and population structure for Penaeidae species, mainly those species occurring in Brazil. Such data can be help to foment future actions aiming the conservation of penaeid species, which present ecological and socioeconomic relevance.