Genetics and linkage of GOT

Genetic control and intracellular localization of GOT isozymes in maize have been described (Scandalios, J. G., Sorenson, J. C., and Ott, L. A., 1975, Biochem. Genet. 13:759-769). They showed that one isozyme was associated with the mitochondrial fraction, one was associated with the soluble fraction, and one with the glyoxysomes. In their materials, only the latter was found to have more than one form. In the wide array of materials that we have studied in maize, we have found five alleles at the locus Got3 associated with the mitochondrial forms, five alleles at the locus Got2 associated with the soluble forms, and at least four alleles at the locus Got1 associated with the glyoxysome forms. In heterozygotes, hybrid bands are produced as a result of interaction between alleles at each of the three loci, suggesting that the maize GOT's are dimers. No hybrid bands are formed between pairs of loci, however.

The Got1 and Got3 loci appear to segregate independently as shown in Table 1. However, analyses of F2 and testcross data involving Got1 with Got2 and Got2 with Got3 indicate that the two pairs of loci are loosely linked (r = 42.3 and r = 42.5, respectively). Thus, the data suggest that all three loci are located on the same chromosome with Got2 between Got1 and Got3. We are attempting to determine the chromosome involved using primary trisomics.

Table 1.

C. W. Stuber and M. M. Goodman


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