It is a study to isolate microsatellite DNA from Leiobagrus marginatus genome with enrichment by magnetic beads.The genomic DNA was first hybridized with a biotin-labeled SSR（simple sequence repeat） probe（ACA）

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and then the 400-900 bp DNA fractions containing SSR sequences were captured by magnetic beads coated with streptavadin.The enriched DNA were inserted into pMD-18 T vector and then transformed into E.coli DH5α competent cells.In this experiment

we performed the second screening with a radiolabeled（ACA）

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probe and obtained 785 positive clones.From 140 positive clones

we isolated 132 microsatellite sequences.This allowed us to designed 64 pairs of primers with the software Primer Premier 5.0.13 microsatellite markers had amplified stably.Using the 13 pairs of primers amplified 4 populations of L.marginalus

L.marginatoides（big size and small size）

L.nigricauda.10 markers showed polymorphism among them.The genetic diversity of these 4 populations was analyzed（using） the 10 markers.