Mitocondrial DNA sequencing of Biomphalaria tenagophila (Orbigny, 1835) (Mollusca: Gastropoda).
With the advent of the automatic sequencing of nucleotides it has been possible in a short period of time to obtain a great amount of information about genomes of different organisms. The mitochondrial DNA sequencing has been considerably increasing in the last years. Just one species of the genus Biomphalaria ? Biomphalaria glabrata ? had its mitochondrial genome totally determined. In this study, the mtDNA of Biomphalaria tenagophila, a mollusc that acts as an intermediary host for Schistosoma mansoni in Brazil, was determined and characterized. This species presents susceptible strains to S. mansoni infection, as well as a totally resistant strain, e.g. the geographic strain originating from the Biological Reserve in Taim (RS, Brazil), that is the target of this study. The size of the actual genome was 13,722 bp: 13 protein coding genes, 22 transfer RNA genes (tRNAs) and two ribosomal subunit genes (rRNAs). Besides the sequencing, analysis of the genome organization of B. tenagophila was performed by gene alignment, contents and localization of the coding and noncoding regions. Sequences of amino acids were compared, as well as of the start and stop codons, nucleotides sequences of the tRNA, rRNA12S and of the rRNA16S and of the organization of genes between B. tenagophila and B. glabrata, the most important intermediary host in Brazil. Besides, we have assembled the secondary structures of six tRNA for B. tenagophila, and evaluated the phylogenetic relation among several molluscs that had their complete mitochondrial genome deposited in the GenBank, using the methods of neighbor-joining, maximum parsimony and maximum likelihood. Some differences in size and composition of genes between B. tenagophila and B. glabrata were detected. The gene order of B. tenagophila and B. glabrata was similar. The complete nucleotide sequence of the mitochondrial genome of B. tenagophila has been submitted to GenBank, and the accession number is EF433576.
Advisor:Paulo Marcos Zech Coelho; Omar dos Santos Carvalho
School:Faculdades Oswaldo Cruz
Source Type:Master's Thesis
Keywords:Biomphalaria tenagophila DNA Mitochondrial IMUNOGENETICA
Date of Publication:04/26/2007