Microsatellite DNA Polymorphisms In Inbred Strain Mice And Selection As Genetic Monitoring Markers

The inbred mouse is the most widely studied animal model in major disciplines of biomedical research. The quality of these animals is a decisive influence on comparative, repetition and veracity of the experiment. With the develop of biomedical research, the more require of qualified mice, the more efficacious genetic monitoring will be needed. Now, methods used in genetic quality control involve the use or biochemical markers, immunologic methods, strain-specific typing sera, morphologic characteristics such as the shape of the mandible, and skin grafting. Since 1980, DNA marker came forth one after another. Among them microsatellite DNA possesses various, scattered wide, high degree of polymorphism, easy to communicate and so on . So this approach is the most usefulness, and it become an ideal genetic marker for gene localization, gene maping, population study and individual identificatinon.Microsatellites consist of around 10-50copies of motifs from 1 to 6 that can occur in perfect tandem repetition. It occurs frequently and randomly in all eukaryotic DNAs examined. Microsatellite DNA are ideal genetic markers due to the high degree of polymorphism and the fact that the variation is readily analyzed using the polymerase chain reaction (PCR).The aim of genetic monitoring is to checking the variance of the animal have been done or not, whether interfuse other strains, which insures that the strains according with the require of colony . At present, the methods based on allozyme biochemistry are the National Standard instructed. Methods that using microsatellite DNA would be more useful for genetic monitoring than methods based on allozyme biochemistry because the genome itself is being tested rather than a protein product and a larger portion of the genome can be sampled, and easy to distinguish. Methods that using microsatellite DNA had abundant microsatelliteloci (over 7300, before 1999) can be identified. Applying enough microsatellite loci will present abundant straps and well polymorphism, which can reflection inherit and variation of roundly genome. In addition, the PCR-based microsatellite analysis is a fast and economical way for detecting genetic contamination . So we should select microsatellite DNA which is polymorphisms as genetic monitoring markers to determining the strains' origin and genetic background of inbred mice. Now only feasibility has been report, and no reports on standards and practicality has been found in our country.With the optimization of components of reaction buffer and amplification parameter, PCR for amplification microsatellite DNA was finally set up. Using the techniques, microsatellite DNA can amplified efficaciously. The final concentrations of Mg2+ was 1 .5 - 3. 0 mmol/L, annealing temperature was 50℃-65℃.The condition for the PCR amplify were ,94℃for 3min, SOcycles of 94℃ for 30s, 50~65"C for 30s, 72℃ for Imin, finally at 72℃for Imin, then store at 4℃. Ten kinds of inbred strain mice including C57BL / 6J, C3H/He, TA,, TA2, 615, BALB/c ,DBA/2N,129/Sv,FVB/N, AMMS/1 were investigated by PCR analysis. This is the first time to genetic monitoring on commonly used inbred mouse strains by the 14 microsatellite DNA . It showed that all these microsatellites DNA loci display single allelic gene band. Fourteen loci are polymorphisms between the inbred strains . The polymorphisms of DlMit365, D2Mit30, D3Mit51, D5Mit48, D6Mit102, D10Mit180, DllMit128, D12Mit147, D14Mitl02 and D17MU36 are significant .These results suggest that these mice tested meet the request of inbred strain. The genetic background of TA, was similar with that of TA2, the similarity indices were from 14. 3%( C57 between 129)to 92. 9%( TA, between TA2).This means that TA, and TA2 had closer genetic relationship, C57 and 129 had farther relationship. Strain 129/Sv is clearly placed at the most deeply diverged of the domesticus strains represented. So it is possible to discriminate between any pair of strains,even closely related and congenic strains. Screened loci showing marked polymorphisms typically...