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Duplicated homeobox genes in Xenopus
A F Fritz1, K W Cho, C V Wright
1Department of Biological Chemistry, University of California, Los Angeles 90024-1737.
Developmental Biology
|February 1, 1989
Summary
The tetraploid frog Xenopus laevis possesses two distinct homeobox gene 2 loci, not allelic variations. This finding suggests duplicated gene complexes, common in Xenopus, influence its genetic diversity.
Area of Science:
- Genetics
- Developmental Biology
- Amphibian Research
Background:
- Tetraploid Xenopus laevis exhibits significant genetic polymorphism.
- Homeobox genes are crucial for development, with conserved roles across vertebrates.
- The Hox 2 gene complex in mammals provides a comparative framework.
Purpose of the Study:
- To investigate the genetic basis of homeobox gene 2 diversity in Xenopus laevis.
- To determine if observed polymorphisms arise from tetraploidy-induced allelic differences or gene duplication.
- To compare Xenopus homeobox gene organization with mammalian counterparts.
Main Methods:
- Isolation and analysis of cDNA and genomic clones for homeobox gene 2.
- Restriction fragment length polymorphism mapping.
- Construction and analysis of Xenopus laevis/Xenopus borealis interspecies hybrids.
Main Results:
- Two distinct restriction maps were identified for homeobox gene 2, suggesting separate loci.
- Analysis of F1 hybrids demonstrated non-independent segregation of homeobox gene 2 transcripts, ruling out allelism.
- Evidence suggests the presence of duplicated Hox 2 complexes in Xenopus laevis.
Conclusions:
- Xenopus laevis harbors two expressed homeobox gene 2 loci, unlike the single locus in mammals.
- The genetic diversity in Xenopus homeobox genes likely results from gene duplication events.
- This duplication pattern appears to be a common feature of Xenopus homeobox gene evolution.