Gene duplication in the family Salmonidae. III. Linkage between two duplicated loci coding for aspartate aminotransferase in the cutthroat trout (Salmo clarki).

Fred W Allendorf,Fred M Utter

doi:10.1111/j.1601-5223.1976.tb01532.x

Fred W Allendorf, Fred M Utter

Open Access

https://doi.org/10.1111/j.1601-5223.1976.tb01532.x

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Abstract

The genetic control of the supernatant form of aspartate aminotransferase (AAT) was studied in the cutthroat trout (Salmo clarki) through a series of experimental matings. 509 individuals of eight families were examined to determine (1) the number of loci, (2) the mode of inheritance (i.e. disomic or tetrasomic), and (3) the linkage relationship of the loci involved. The variation observed is controlled by a duplicated locus resulting from a presumed tetraploid event of an ancestral salmonid. The inheritance experiments revealed the presence of two disomic loci rather than a single tetrasomic locus, indicating that disomy has been reestablished for the chromosomes carrying the AAT loci. The two families in which linkage between these loci could be tested displayed significant nonrandom segregation between these loci with an estimated frequency of recombination of 30.6%. These results are discussed in regard to the proposed evolution of tetraploidy in the family Salmonidae.

Highlights

Recommended Citation Allendorf, Fred W. and Utter, Fred M., "Gene duplication in the family Salmonidae 111
Forty sexually mature cutthroat trout were examined and 15 matings made on the basis of the parental genotypes for aspartate aminotransferase (AAT) as well as other enzymes not reported here
Sufficient time has elapsed since the presumed tetraploid event early in salmonid evolution to allow the reestablishment of disomy in at least the great majority of loci

Summary

Introduction

Recommended Citation Allendorf, Fred W. and Utter, Fred M., "Gene duplication in the family Salmonidae 111. The two families in which linkage between these loci could be tested displayed significant nonrandom segregation between these loci with an estimated frequency of recombination of 30.6x, These results are discussed in regard to the proposed evolution of tetraploidy in the family Salmonidae. OHNOhas proposed that the salmonid lineage has gone through an additional tetraploid event on the basis of this gene multiplicity, comparative amounts of DNA, and certain chromosomal characteristics (OHNO1974). Because of this additional gene duplication the salmonids represent an excellent opportunity to study the evolution of duplicated genes in a group of vertebrate species

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