Preliminary investigations in our laboratory have revealed evidence of synteny between the loci encoding for Alcohol Dehydrogenase (ADH) and Glutamic Oxaloacetic Transaminase-1 (GOT-1 in natural populations of the deer mouse, Peromyscus maniculatus. Linkage analyses were conducted by lod-score iterations of electrophoretic differences. Also, our studies have yielded evidence that different selection regimes may be operating on these two enzyme systems. However, much of this evidence is based upon a sample of ten mother-offspring combinations. Our specific objectives in this proposal are as follows: (1) Obtain a set of allozyme and geneotype frequencies for a large field population of deer mice known to be polymorphic for ADH, GOT-1, SDH, and EST-4; (2) Obtain a set of mother-offspring genotype combinations for use in lod-score and selection analyses; and (3) Test hypotheses concerning the relationships and limitations of ADH genotypes in conjunction with varying genetic backgrounds composed of polymorphic proteins (isozymes). The proposed methodology will provide conclusive results on the chromosomal relationships between ADH and GOT-1 in the deer mouse, and lend insight into the various selective controls operating on these systems. Also, this information should be useful to understanding the health-related aspects of ADH and its relationship to differences in co-acting genetic backgrounds.