Microsatellite markers in wood mouse and striped field mouse (genus Apodemus).

To study possible effects of radiation and chemical pollutants on native rodents in highly polluted sites of the former Soviet Union we developed a system of microsatellite markers in mice (Apodemus). Microsatellites can provide information on mutation rate and population structure of the affected animals. Dubrova et al. (1996) reported that mutation rates at minisatel-lite loci in humans who lived in heavily polluted areas of Belarus after the Chernobyl accident were twice as high as that of the control group. No genetic studies have been done thus far on humans or animals in the vicinity of Chelyabinsk, Russia, one of the Earth's most radioactively and chemically polluted spots. Here, we report the development of 13 het-erospecific microsatellites that amplify the DNA from both the wood mouse (Apodemus sylvaticus) and the striped field mouse (A. agrarius). Polymorphism of the microsatellite markers is described in animals collected near Chelyabinsk. Mice of the genus Apodemus comprise a dominant group of murid rodents in the Palaearctic region (Corbet 1978). The two species we are studying (A. agrarius and A. sylvaticus) belong to different subgenera (Apodemus and Sylvaemus, respectively). Mice of this genus are commonly available at polluted sites and both A. sylvaticus and A. agrarius are widely distributed so that comparative studies are possible. According to several allozyme studies (e.g. Hartl et al. 1992), the genetic distance between A. agrarius and A. sylvaticus is much greater than is typical between rodent congeners. Small-insert genomic libraries were constructed for A. agrarius and A. sylvaticus basically following the method described by Hillis et al. (1996). Total genomic DNA was isolated from two individual mice A. agrarius (TK44878) and A. sylvaticus (TK44936). Two libraries were constructed for each individual mouse: one after digesting the genomic DNA with ApoI (cloned into EcoRI site of pBluescript SK+), and the other after digesting the genomic DNA with DpnII (cloned into the BamHI site of pBluescript SK+). pBluescript SK+ (Stratagene) was dephosphorylated before ligation. XL-1 Blue ultracom-petent cells (Stratagene) were used for transfection. All four libraries were hybridized with [γ-32 P] end-labelled repeat-containing oligonucleotides: (CA) 11 , (GGT) 5 , (GTT) 6 , (GATA) 6 and (GACA) 5. Positive clones were archived for secondary screening. Secondary screening revealed the following results: 36 (CA) n , seven (GGT) n , 23 (GTT) n , 17 (GATA) n and eight (GACA) n positive clones. From these clones we describe 12 primer pairs with …