[Prospects for obtaining a mapping panel for somatic cell marsupial-rodent hybrids for the short-tailed opossum...

A possibility of obtaining a panel of marsupial-rodent somatic cell hybrid clones has been explored, with a view to mapping the genome of the opossum (Monodelphis domestica). Fusion of opossum cells (splenocytes, bone marrow cells, and fibroblasts) with fibroblasts of Chinese hamster or vole (HGPRT- and TK- mutants, respectively) produced 146 hybrid clones. The majority of marsupial-mammalian somatic cell hybrids were characterized by pronounced fragmentation and segregation of marsupial chromosomes. To overcome this difficulty, a method for rapid screening was developed, which allowed the early selection of clones rich in chromosomal material of opossum. Based on the screening results, 25 clones of independent origin were selected. A detailed genetic analysis, which included chromosome G-banding and in situ hybridization of biotin-labeled opossum DNA on metaphase chromosomes, allowed further selection of seven hybrid clones containing one to six intact chromosomes of M. domestica. Opossum chromosomes were present in various combinations against the background of Chinese hamster or vole chromosomes. The clones will be included in the panel of opossum-rodent somatic cell hybrids, which is currently being created.