This preview shows page 1. Sign up to view the full content.
Unformatted text preview: 434 Chapter 13 The Dynamic Genome: Transposable Elements 13.3 Transposable elements in eukaryotes Although transposable elements were first discovered in maize, the first eukaryotic elements to be molecularly characterized were isolated from mutant yeast and Drosophila genes. As shown in Figure 13-1, eukaryotic transposable elements fall into two classes: class 1 retro- transposons and class 2 DNA transposons. The first class to be isolated, the retrotransposons, were not at all like the prokaryotic IS elements and transposons. Class I: retrotransposons The laboratory of Gerry Fink was among the first to use yeast as a model organism to study eukaryotic gene reg- ulation. Through the years, he and his colleagues isolated thousands of mutations in the HIS4 gene, which codes for one of the enzymes in the pathway leading to the synthesis of the amino acid histidine. They isolated more than 1500 spontaneous HIS4 mutants and found that two of them had an unstable mutant phenotype. The unstable mutants had a rever-mutant phenotype....
View Full Document
- Spring '08