Nucleotide sequences have been used to distinguish species and specimens for many years. More recently, the use of a partial sequence of 650 bp of the cytochrome c oxidase I, COI mitochondrial gene, has been proposed for species identification, known as DNA barcodes. In this work, a short sequence of the DNA barcode is described—approximately 250 bp, named as “DNA mini-barcode”—to molecularly identify different silkworm strains maintained at the unique public Germplasm Bank of Bombyx mori, at the Universidade Estadual de Maringá, UEM, Brazil. Analysis revealed no significant differences among the silkworm strains. The phylogenetic tree obtained by the neighbor-joining method and K2P distance, in which specimens of B. mandarina were used as outgroup, clustered all the specimens of B. mori in a unique clade. Genetic variability detect within B. mori was low or nonexistent. In conclusion, the partial region of 250 bp of the mitochondrial gene COI herein analyzed may not be efficient to discriminate silkworm strains from the UEM Germplasm Bank of Bombyx mori.
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