Resumo

JIMENEZ OCAMPO, Rafael et al. Genetic diversity of the msp1a gene variable region and msp4 gene of Anaplasma marginale strains from Mexico. Rev. mex. de cienc. pecuarias [online]. 2012, vol.3, n.3, pp.373-386. ISSN 2448-6698.

Control of anaplasmosis is limited due to the rickettsia's wide genetic diversity. Major surface protein (Msp) 1a is composed of one constant region and a variable region which may contain one or more 23 - 31 aminoacid repeat sequences. Mspla variable region together with Msp4 have been used for phylogenetic purposes. We analyzed the variable region of Msp1a and Msp4 gene of ten new Mexican A. margínale strains and compared with previously published sequences in order to correlate the structure of these genes with geographic distribution. In the case of Msp1a, there were geographically distant strains that shared the same variable region, whereas strains from the same outbreak or the same region showed very different structures. Wide diversity in this region had been observed with previous analysis yet a pattern composed by several repeats emerged along organisms isolated from the Mexican gulf coast states. This variation can be explained in part by the immune system pressure over the organism, yet other independent transmission events have to be considered. In the case of Msp4, little variation was observed at the nucleotide level which did not affect the amino acid structures along the new strains analyzed, yet there are differences with previously published for Mexican isolates.

Palavras-chave : Anaplasma marginale; Surface proteins; Msp1a; Msp4; Genetic diversity; México; Cattle; Bovine anaplasmosis.

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