Mutation and selection explain why many eukaryotic centromeric DNA sequences are often A+T rich

Barbosa, Anne C; Xu, Zhengyao; Karari, Kazhal; Williams, Wendi; Hauf, Silke; Brown, William R A

Abstract

We have used chromosome engineering to replace native centromeric DNA with different test sequences at native centromeres in two different strains of the fission yeast Schizosaccharomyces pombe and have discovered that A + T rich DNA, whether synthetic or of bacterial origin, will function as a centromere in this species. Using genome size as a surrogate for the inverse of effective population size (Ne) we also show that the relative A + T content of centromeric DNA scales with Ne across 43 animal, fungal and yeast (Opisthokonta) species. This suggests that in most of these species the A + T content of the centromeric DNA is determined by a balance between selection and mutation. Combining the experimental results and the evolutionary analyses allows us to conclude that A + T rich DNA of almost any sequence will function as a centromere in most Opisthokonta species. The fact that many G/C to A/T substitutions are unlikely to be selected against may contribute to the rapid evolution of centromeric DNA. We also show that a neo-centromere sequence is not simply a weak version of native centromeric DNA and suggest that neo-centromeres require factors either for their propagation or establishment in addition to those required by native centromeres.

Citation

Barbosa, A. C., Xu, Z., Karari, K., Williams, W., Hauf, S., & Brown, W. R. A. (2022). Mutation and selection explain why many eukaryotic centromeric DNA sequences are often A+T rich. Nucleic Acids Research, 50(1), 579-596. https://doi.org/10.1093/nar/gkab1219

• Journal Article Type: Article
• Acceptance Date: Nov 30, 2021
• Online Publication Date: Dec 20, 2021
• Publication Date: Jan 11, 2022
• Deposit Date: Dec 13, 2021
• Publicly Available Date: Dec 20, 2021
• Journal: Nucleic Acids Research
• Print ISSN: 0305-1048
• Electronic ISSN: 1362-4962
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 50
• Issue: 1
• Pages: 579-596
• DOI: https://doi.org/10.1093/nar/gkab1219
• Keywords: Genetics
• Public URL: https://nottingham-repository.worktribe.com/output/7014319
• Publisher URL: https://academic.oup.com/nar/article/50/1/579/6470688