Electrophoretic studies on polyploid amphibians—III. Lack of locus duplication evidences through tetraploidization

Abstract

1. 1. An investigation of 9 enzymatic systems by starch-gel and polyacrylamide electrophoreses in the tetraploid and diploid species Odontophrynus americanus and O. cultripes is presented. The electrophoretic patterns of five enzymes in the glucose-metabolizing system (critical enzymes) and 4 enzymes (peripheral enzymes) which were not directly involved in the above-mentioned system are compared which resulted in the conclusion that the diploid and tetraploid populations of O. americanus are identical in mobility and number of bands. 2. 2. Comparison between the tetrapoloid O. americanus and a closely related diploid species O. cultripes shows that the critical enzymes, ODH and ADH, exhibit equal number of bands. Most enzymes studied differ in the relative mobility of their bands, with the exception of HBDH, ADH and ODH. 3. 3. Polymorphism is detected for the tetrazolium oxidase (TO), due to two alleles F and S, both in the diploid and tetraploid species of O. americanus and in O. cultripes. The tetraploid O. americanus differs from the diploid species in having two extra phenotypes, suggesting a tetrasomic mode of inheritance. Electrophoreses of individual oocytes show that, in the tetraploid O. americanus, the four genes for TO are active in each cell. 4. 4. Our present results support the assumption that O. americanus 4n is a recent autotetraploid. Gene duplications detected in the tetraploid are prior to polyploidy.