The C57BL/6J (B6) inbred mouse strain is commonly used in biomedical researches. However, some unexpected inconsistency was reported compared with previous studies, and in most cases, it can be attributed to environmental, epigenetic or stochastic differences. The goal of this study was to investigate the genetic stability of the B6 strain maintained in different breeders. B6 mice purchased from five Chinese commercial breeders were examined, and mitochondrial D-loop sequence and 18 microsatellite loci were genotyped. There is no difference in the D-loop sequences, but variations exist in the nucleic microsatellite markers. Combining the data from MGI_4.01, a significant divergence is observed among those mice. The present study indicates that different B6 mice share the common maternal lineage and are still inbred in each breeder, but subline divergence occurs.

Abstract:The goal of this study was to investigate the genetic stability of the C57BL/6J (B6) inbred mouse strain maintained in different breeders. Three populations of B6, Pop1 and Pop2 purchased from Beijing and Pop3 purchased from Shanghai, were examined. Fifteen microsatellite loci reported to be polymorphic among inbred strains were amplified using FAM labeled primers and genotyped with ABI Prism 377 automated sequencer. Seven loci were found polymorphic, and all the loci were homozygous in all the three populations. The present study indicates that genetic variation occurs in different B6 populations although they are still inbred in each breeder. The mechanism of genetic variation is not well understood now, but it is very important to know the precise content of the B6 genome before use of this strain in research.

Abstract:The retroviral vector (RCAS) has been widely used in avian system to study development and diseases, but is not suitable for mammals which do not produce the retrovirus receptor TVA. In this review, we trace the current uses of RCAS-TVA approach in mammalian system with improved strategies, including generation of tv-a transgenic mice, use of soluble TVA receptor and retroviral receptor-ligand fusion proteins, improvement of RCAS vectors, and compare a series of mammalian models in variant studies of gene function, development, oncogenesis and gene therapy. All those studies demonstrate that the RCAS-TVA based mammalian models are powerful tools for understanding the mechanisms and target treating of human diseases.