Molecular evolution of theSaccharomyces cerevisiae histone gene loci
- 30 Downloads
The core histone genes ofSaccharomyces cerevisiae are arranged as duplicate nonallelic sets of specifically paired genes. The identity of structural organization between the duplicated gene pairs would have its simplest evolutionary origin in the duplication of a complete locus in a single event. In such a case, the time since the duplication of one of the genes should be identical to that since duplication of the gene adjacent to it on the chromosome. A calculation of the evolutionary distances between the coding DNA sequences of the histone genes leads to a duplication paradox: The extents of sequence divergence in the silent component of third-base positions for adjacent pairs of genes are not identical. Estimates of the evolutionary distance between the two H3-H4 noncoding intergene DNA sequences are large; the divergence between the two separate sequences is indistinguishable from the divergence between either of the regions and a randomly generated permutation of itself. These results suggest that the duplication event may have occurred much earlier than previously estimated. The potential age of the duplication, and the attractive simplicity of the duplication of both the H3-H4 and the H2A-H2B gene pairs having taken place in a single event, leads to the hypothesis that modern haploidS. cerevisiae may have evolved by diploidization or fusion of two ancient fungi.
Key wordsHistone genes Gene conversion Diploidization Yeast
Unable to display preview. Download preview PDF.
- Fogel S, Mortimer RK, Lusnak K (1981) Mechanisms of meiotic gene conversion, or “Wanderings on a Foreign Strand”. In: Strathern JN, Jones EW, Broach JR (eds) The molecular biology of the yeastSaccharomyces. Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, pp 289–339Google Scholar
- Grunstein M, Rykowski M, Kolodrubetz D, Choe J, Wallis JW (1984) A genetic analysis of histone protein subtypes in yeast. In: Stein GS, Stein JL, Marzluff WF (eds) Histone genes. John Wiley & Sons, New York, pp 35–63Google Scholar
- Johnson ML, Frasier SG (1985) Non-linear least squares analysis. Methods Enzymol 117:301–342Google Scholar
- Smith MM (1984) The organization of the yeast histone genes. In: Stein GS, Stein JL, Marzluff WF (eds) Histone genes. John Wiley & Sons, New York, pp 3–33Google Scholar
- Stiles JI, Friedman LR, Sherman F (1981) Studies on transposable elements in yeast. II. Deletions, duplications, and transpositions of the COR segment that encompasses the structural gene of yeast iso-1-cytochrome c. Cold Spring Harbor Symp Quant Biol 45:602–607Google Scholar