Linkage group IV of fish of the genusXiphophorus(Poeciliidae): Assignment of loci coding for pyruvate kinase-1, glucosephosphate isomerase-1, and isocitrate dehydrogenase-1

✍ Scribed by Donald C. Morizot; Michael J. Siciliano

• Publisher: Springer
• Year: 1982
• Tongue: English
• Weight: 708 KB
• Volume: 20
• Category: Article
• ISSN: 0006-2928
• DOI: 10.1007/bf00484701

✦ Synopsis

Electrophoretic variation ascribable to three enzyme loci, coding for a pyruvate kinase (PK1), a glucose phosphate isomerase (GPI1), and an isocitrate dehydrogenase (IDH1), was observed in three species offish of the genus Xiphophorus. Electrophoretie patterns in FI hybrid heterozygotes confirmed the dimeric structures of GPI and IDH, and indicated a multimeric structure for pyruvate kinase. Variant alleles at the three loci exhibited normal Mendelian segregation in backcross hybrids. Linkage analyses indicate a gene order and estimated recombination of PK1--IO%--GPI1--41%--IDH1. No significant interference or sex-or population-specific recombination difference was detected. This group (designated linkage group IV) was shown to assort independently from the nine loci comprising linkage groups I, II, and III and from 23 other informative markers, within the limits of the data. No conclusions with respect to homology of linkage relationships could be reached, due to the presence of presumably duplicated loci in these fish coding for isozymes whose homology with enzymes in other vertebrate species is as yet unestablished. KEY WORDS: linkage; fish genetics; isozymes; electrophoresis; Xiphophorus; gene mapping.

Introduction

Poeciliid fish of the genus Xiphophorus, especially X. maculatus (platyfish) and X. helleri (swordtails), have been the objects of genetic research for over