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Title: SINGLE STRAND CONFORMATION POLYMORPHISM ANALYSIS DISCRIMINATES GREENBUG (HOMOPTERA: APHIDIDAE) MTDNA HAPLOTYPES

Author
item Shufran, Kevin
item RANGASWAMY, V
item Burd, John
item Porter, David

Submitted to: Journal of Agricultural and Urban Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/8/2005
Publication Date: 12/1/2005
Citation: Shufran, K.A., Rangaswamy, V., Burd, J.D., Porter, D.R. 2005. Single strand conformation polymorphism analysis discriminates greenbug (Homoptera: Aphididae) mtDNA haplotypes. Journal of Agricultural and Urban Entomology. 22(1):49-54.

Interpretive Summary: The greenbug aphid (Schizaphis graminum) is an important pest of wheat and sorghum in the United States and other areas of the world. In a previous study using DNA sequencing, we identified three genetically distinct greenbug types, which closely corresponded to a specific host/ecosystem; crops (wheat, sorghum), Agropyron spp. wheat grasses, and a mixture of other wild grass species. To further advance our knowledge of greenbug genetics and evolution, a survey of the distribution of these distinct types within the greenbug species is needed. However, DNA sequencing is a time consuming and expensive procedure, which makes analyses of many individuals prohibitive in such a large-scale population study. Therefore, we developed a more cost and time efficient method of genetic markers (single strand conformation polymorphisms, or SSCP), which are able to classify individual greenbugs into each of the 3 genetic, types previously only identifiable by DNA sequencing.

Technical Abstract: Single strand conformation polymorphism (SSCP) analysis discriminated three mtDNA haplotypes in the greenbug, Schizaphis graminum (Rondani), previously identified by sequencing a 1.0-1.2 kb portion of the cytochrome oxidase subunit I (COI) gene. Neighbor-joining, maximum parsimony, and maximum likelihood analysis of the first 500 b of the original 1.2 kb fragment of the COI all produced dendrograms identical to that done with analyses of the larger fragment. This 500 b fragment was PCR amplified and the products subjected to SSCP on native polyacrylamide gels. Unique bands and Rf values identified greenbug biotypes and isolates, corresponding to three haplotypes. SSCP analysis offers a more time and cost efficient method than DNA sequencing to identify mtDNA haplotypes in the greenbug, and yields more informative genetic data than traditional biotype determination.