Related Experiment Video
Updated: Feb 11, 2026

Studying Age-dependent Genomic Instability using the S. cerevisiae Chronological Lifespan Model
Published on: September 29, 2011
sic1 mutation leads to rDNA instability by partial duplication with SIR4
Taichi Murai1,2, Shuichi Yanagi1, Yutaro Hori1
1Laboratory of Genome Regeneration, Institute for Quantitative Biosciences (IQB), The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
Abstract:
The ribosomal RNA gene cluster (rDNA) in Saccharomyces cerevisiae consists of about 150 tandem copies, making it a fragile site prone to copy number changes through recombination among the repeat. While extensive research has been conducted to understand the mechanisms for rDNA stability maintenance, the relationship between the stability maintenance of rDNA and other genomic regions remains unclear. In this study, we identified a mutant, sic1, that exhibited instability in both rDNA and chromosome IV (chr.IV). We revealed that Ty element-mediated ectopic recombination leads to partial duplication and elongation of chr.IV. Furthermore, we found that rDNA instability is caused by an increased SIR4 gene dosage resulting from this partial duplication. These findings suggest a link between the stability of rDNA and other genomic regions.
Related Concept Videos
Mutations
Viral Mutations
Centrosome Duplication
To ensure that each daughter cell receives a centrosome after cell division, centrosome duplication...
Microtubule Instability
Gene Duplication and Divergence
The duplicated copies of the gene are called Paralogs. Paralogs with similar sequences and functions form a gene family. Across several species, a large number of gene families are...
Duplication of Chromatin Structure
The basic unit of the chromatin is the nucleosome, consisting of DNA wrapped around octameric histone proteins and short stretches of linker DNA separating individual nucleosomes. The histone proteins within the nucleosome have their...

