Análise da viabilidade do gene 28s para a delimitação molecular do gênero Macrobrachium

Abstract

Crustaceans are an important ecologically and economically important group. The order of the Decapods stands out for its diversity, but mainly for its relevance in the market, because within this group are the individuals most consumed globally. However, there is still a lack of techniques capable of making complete analyzes, since the identification is mainly done in a morphological way, making room for errors and erroneous classifications. One of the possible alternatives to solve this problem, provide reliable data and generate reliable information is to combine several morphological, morphometric, environmental and molecular approaches. With this, molecular biology has begun to explore the use of molecular markers as a possibility, but this approach also faces its limitations, one of which is the presence of heteroplasmy and pseudogenes in the nucleotide sequences. These factors can lead to an erroneous amplification of the bases and consequently few insurance data. An alternative to cure this problem is to make use of more complete regions, having conserved and varied portions, with that, the use of the 28S gene for molecular identification of this group was started. This work aimed to analyze the viability of the 28S gene in the molecular delimitation of Macrobrachium through phylogenetic analyzes, intra and interspecific distance calculations and, finally, ABGD analysis. For this 321 Genbank sequences were obtained and sorted out and subjected to the above analyzes. The results of the Tree and ABGD were positive, since the grouping was satisfactory, bringing together all the species close to each other. The data from the distances confirmed that the barcode gap was necessary to distinguish species within the genus. Therefore, the efficiency of this marker to discriminate species, since the analyzes were shown to be congruent with the gene tree and with the intra and intraspecific distances, evidencing the presence of a barcode can be used as a complementary tool as an alternative identification the species that are difficult to separate using only morphological data.