Evolution and homoplasy at the bem6 microsatellite locus in three Bemisia tabaci cryptic species

The evolution of individual microsatellite loci is often complex and homoplasy is common but often goes undetected. Sequencing alleles at a microsatellite locus can provide a more complete picture of the common evolutionary mechanisms occurring at that locus and can reveal cases of homoplasy. Within species homoplasy can lead to an underestimate of differentiation among populations and among species homoplasy can produce a misleading interpretation regarding shared alleles and hybridization. This is especially problematic with cryptic species. By sequencing alleles from three cryptic species of Bemisia tabaci, designated MEAM1, MED, and NW, the evolution of the Bem6 (CA₈)_imp microsatellite locus is inferred as one of primarily stepwise mutation occurring at four distinct heptaucleotide tandem repeats. In two of the species this pattern yields a compound tandem repeat. Homoplasy was detected both among species and within species. In the absence of sequencing, size homoplasious alleles would lead to an overestimate of alleles shared and hybridization among cryptic species.