Genome-wide mapping of spontaneous genetic alterations in diploid yeast cells.

Journal Article (Journal Article)

Genomic alterations including single-base mutations, deletions and duplications, translocations, mitotic recombination events, and chromosome aneuploidy generate genetic diversity. We examined the rates of all of these genetic changes in a diploid strain of Saccharomyces cerevisiae by whole-genome sequencing of many independent isolates (n = 93) subcloned about 100 times in unstressed growth conditions. The most common alterations were point mutations and small (<100 bp) insertion/deletions (n = 1,337) and mitotic recombination events (n = 1,215). The diploid cells of most eukaryotes are heterozygous for many single-nucleotide polymorphisms (SNPs). During mitotic cell divisions, recombination can produce derivatives of these cells that have become homozygous for the polymorphisms, termed loss-of-heterozygosity (LOH) events. LOH events can change the phenotype of the cells and contribute to tumor formation in humans. We observed two types of LOH events: interstitial events (conversions) resulting in a short LOH tract (usually less than 15 kb) and terminal events (mostly cross-overs) in which the LOH tract extends to the end of the chromosome. These two types of LOH events had different distributions, suggesting that they may have initiated by different mechanisms. Based on our results, we present a method of calculating the probability of an LOH event for individual SNPs located throughout the genome. We also identified several hotspots for chromosomal rearrangements (large deletions and duplications). Our results provide insights into the relative importance of different types of genetic alterations produced during vegetative growth.

Full Text

Duke Authors

Cited Authors

  • Sui, Y; Qi, L; Wu, J-K; Wen, X-P; Tang, X-X; Ma, Z-J; Wu, X-C; Zhang, K; Kokoska, RJ; Zheng, D-Q; Petes, TD

Published Date

  • November 10, 2020

Published In

Volume / Issue

  • 117 / 45

Start / End Page

  • 28191 - 28200

PubMed ID

  • 33106417

Pubmed Central ID

  • PMC7668089

Electronic International Standard Serial Number (EISSN)

  • 1091-6490

Digital Object Identifier (DOI)

  • 10.1073/pnas.2018633117

Language

  • eng

Conference Location

  • United States