Chinese hamster x American mink somatic cell hybrids were obtained and examined for chromosome content and expression of mink malate dehydrogenase, NADP (MOD-1; EC 1.1.1.40), malate dehydrogenase, NAD (MOR-1; EC 1.1.1.37), glucose-6-phosphate dehydrogenase (G6PD; EC 1.1.1.49) and hypoxanthine phosphoribosyltransferase (HPRT; EC 2.4.2.8). All the hybrid clones examined were found to segregate mink chromosomes. A clone panel containing 25 clones was set up. The possibilities and limitations of this panel for mink gene mapping are analysed. Using this panel, it is feasible to rapidly map genes located on chromosomes 1-13 and to provisionally assign genes located on chromosome 14 and the X. Based on the data obtained, the genes for MOD-1 and MOR-1 were firmly assigned to mink chromosomes 1 and 11, respectively, and the genes for G6PD and HPRT were provisionally assigned to the X.

Twenty-eight American mink × Chinese hamster somatic cell hybrids were analysed for the expression of mink enzymes and the segregation of mink chromosomes. The results demonstrated that the gene for enolase-1 is located on the long arm of mink chromosome 2, and those for hexokinase-1 and adenosine kinase, on its short arm. Segregation analysis of mink chromosomes and mink acid phosphatase-2, mannose phosphate isomerase, inosine triphosphatase and aconitase-1 provided data allowing us to assign the genes for these markers to mink chromosomes 7, 10, 11 and 12, respectively. The expression of mink α-galactosidase was highly coincidental with mink × chromosome as well as with its markers: hypoxanthine-phosphoribosyltransferase, glucose-6-phosphate dehydrogenase and phosphoglycerate kinase-1. This result confirms the assignment of the gene for α-galactosidase to the mink × chromosome.

Twenty eight American mink × Chinese hamster somatic cell hybrids were analysed for the expression of mink enzymes and chromosome segregation. This analysis made it possible to assign the genes for glutamate-oxaloacetate transaminase-1 (soluble) (EC 2.6.1.1), inorganic pyrophosphatase (EC 3.6.1.1), purine nucleoside phosphorylase (EC 2.4.2.1) to mink chromosome 2, superoxide dismutase-1 (soluble) (EC 1.11.1.1) to chromosome 5, peptidase A (EC 3.4.11 or 3.4.13) to chromosome 4, and peptidase C (EC 3.4.11 or 3.4.13) to chromosome 13. It is suggested that the synthenic gene group GOT1-PP-NP is located on the short arm of mink chromosome 2.

Segregation of the X-linked mink markers α-galactosidase (GLA), phosphoglycerate kinase-1 (PGK1), hypoxanthine phosphoribosyltransferase (HPRT), and glucose-6-phosphate dehydrogenase (G6PD) was analyzed in hybrids of gamma-irradiated mink fibroblasts and Chinese hamster cells and in hybrids of nonirradiated mink fibroblasts and mouse hepatoma cells. Based on this analysis, the order of the four genes is GLA-PGK1-HPRT-G6PD on the mink X chromosome. Cytogenetic analysis of five mink × Chinese hamster hybrid clones containing mink GLA, PGK1, and HPRT, but lacking G6PD, tentatively localized mink G6PD to Xq 15.22→qter and also confirmed the gene order as GLA-PGKl-HPRT-G6PD-qter. Comparison of this order with its counterpart in man and the mouse, as well as an analysis of the G-band patterns of their X chromosomes, demonstrated putative similarities between mink and man and differences in the mouse. These differences may be due to a different rate of X-chromosomal rearrangement in mammalian evolution.

A panel of clones of mink-Chinese hamster somatic cell hybrids was analysed to obtain data for assigning the genes for thymidine kinase-1 (TK1), galactokinase (GALK), subunit C of aldolase (ALDC), and esterase D (ESD) to specific mink chromosomes. The results demonstrate that the genes for TK1, GALK, ALDC and ESD are syntenic and located on mink chromosome 8. Prometaphase analysis of transformed mouse cells obtained by transfer of mink genes by means of metaphase chromosomes demonstrated the presence of mink chromosome 8 fragments of different sizes in some of the independent transformants. Segregation analysis of these fragments and mink TK1, GALK, ALDC and ESD allowed us to assign the genes for TK1 and GALK to 8p24, ALDC to pter-8p25, and ESD to 8q24-8qter.