Abstract: Microsatellites are simple tandemly repeated sequence with repeat units of 1-6 bp in length. As genetic markers, microsatellites are widely dispersed in eukaryotic genomes. The advantages of microsatellites include high polymorphism, high abundance, co-dominance, selective neutrality and high reliability. There are three kinds of techniques to analyze microsatellites: repeat-sequence hybridization fingerprints, repeat-sequence primer PCR fingerprints and single-locus microsatellite PCR. The first two kinds belong to multiple-locus markers, and the last one is single-locus marker and generally named `microsatellite marker'. Up to now, 141 microsatellite loci were cloned from 14 aphid species, and primers for them were published, which provided abundant information for future studies. In addition, these primers probably work in closely related species. Conforming to Mendel's law, microsatellites were successfully used to speculate sex recombination in some species. Sexual and asexual lineages may coexist in a single aphid species. Microsatellites revealed that genetic diversities were generally higher in sexual lineages than in asexual lineages, but asexual lineages often exhibited heterozygote excesses and linkage disequilibrium. Microsatellites were also effective in studying migration of aphid. Low differentiations and high allelic frequency homogeneity were revealed in highly migratory aphids. The distribution of identical multilocus genotypes was directly used as an indicator of migration ambit. Until now, microsatellites have been rarely used in aphid study by domestic researchers in China. It has been proved that microsatellites are excellent genetic markers, so we expect to see more application of this kind of marker in aphid study.  

Key words: SSR, microsatellite marker, aphid, genetic structure, geographical population