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C K Chai

Publications and source records attributed to C K Chai.

31 records · Page 2Linked to original sources
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Genes associated with leukocyte production in mice.

We have investigated the genes influencing leukocyte production in mice by selective breeding for differences in leukocyte count and developed two major lines differing about 8-fold. In these lines we have made counter selective breeding, crossbreeding between them, and developed methods of using marker genes to search for individual genes distributed on different chromosomes. We have revealed an overall dominance of genes for low leukocyte count over those for high counts, and effects of genes at the agouti locus, certain mutant genes, and a gene or genes in the XVI linkage group. We have commented on the application and approach of quantitative genetic experimentation from both a theoretical and practical point of view and, on the basis of present results, discussed the nature of polygenes in relation to genes causing polymorphisms.

Animals↗
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Dactylaplasia in mice a two-locus model for development anomalies.

Dactylaplasia, characterized by the absence of phalangeal bones in the middle digits of each foot, resulted from a mutation that occurred in the SM7B/SM inbred strain of mice. Breeding tests revealed the mutant gene is an autosomal dominant that is homozygous lethal. Further investigation by outcrossing with a number of inbred strains showed that the manifestation of the mutant gene is controlled by another locus. At this locus are found two alleles: one, a dominant inhibiting dactylaplasia gene expression; the other, a recessive allowing the expression of the mutant gene. In each of the tested inbred strains, one or the other allele is present at this locus. We propose Dac as a symbol for the mutant gene, and mdac for the locus controlling the Dac expression. Mouse dactylaphasia closely resembles split hand/foot in man and in monkeys in gross morphology and mode of inheritance. The significance of the present findings explainable by a two-locus model is discussed relative to irregular mode of inheritance of certain other congenital defects, and also relative to the maintenance of genetic loads in populations.

Animals↗