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Studies conducted at Washington State University on genetics recently published
2009 AUG 4 - (NewsRx.com) -- Fresh data on genetics are presented in the report 'Generation of antigenic variants via gene conversion: Evidence for recombination fitness selection at the locus level in Anaplasma marginale.' "Multiple bacterial and protozoal pathogens utilize gene conversion to generate antigenically variant surface proteins to evade immune clearance and establish persistent infection. Both the donor alleles that encode the variants following recombination into an expression site and the donor loci themselves are under evolutionary selection: the alleles that encode variants that are sufficiently antigenically unique yet retain growth fitness and the loci that allow efficient recombination," researchers in the United States report. "We examined allelic usage in generating Anaplasma marginale variants during in vivo infection in the mammalian reservoir host and identified preferential usage of specific alleles in the absence of immune selective pressure, consistent with certain individual alleles having a fitness advantage for in vivo growth. In contrast, the loci themselves appear to have been essentially equally selected for donor function in gene conversion with no significant effect of locus position relative to the expression site or origin of replication. This pattern of preferential allelic usage but lack of locus effect was observed independently for Msp2 and Msp3 variants, both generated by gene conversion. Furthermore, there was no locus effect observed when a single locus contained both msp2 and msp3 alleles in a tail-to-tail orientation flanked by a repeat. These experimental results support the hypothesis that predominance of specific variants reflects in vivo fitness as determined by the encoding allele, independent of locus structure and chromosomal position," wrote J.E. Futse and colleagues, Washington State University. The researchers concluded: "Identification of highly fit variants provides targets for vaccines that will prevent the high-level bacteremia associated with acute disease." Futse and colleagues published their study in Infection and Immunity (Generation of antigenic variants via gene conversion: Evidence for recombination fitness selection at the locus level in Anaplasma marginale. Infection and Immunity, 2009;77(8):3181-7). For additional information, contact J.E. Futse, Washington State University, Dept. of Veterinary Microbiology and Pathology, Pullman, 99164 USA.. Publisher contact information for the journal Infection and Immunity is: Springer, 233 Spring Street, New York, NY 10013, USA. Keywords: United States, Pullman, Genetics, Immunology. This article was prepared by Life Science Weekly editors from staff and other reports. Copyright 2009, Life Science Weekly via NewsRx.com.
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