Mutational Landscape of Spontaneous Base Substitutions and Small Indels in Experimental Caenorhabditis elegans Populations of Differing Size

• DOI: 10.1101/529214
• Publication Date: 2019-01-24T10:38:28Z
• Authors: Anke Konrad; Meghan J. Brady; Ulfar Bergthorsson; Vaishali Katju
• Keywords: Indel; Nonsynonymous substitution; Effective population size

ABSTRACT Experimental investigations into the rates and fitness effects of spontaneous mutations are fundamental for our understanding evolutionary process. To gain insights molecular consequences mutations, we conducted a mutation accumulation (MA) experiment at varying population sizes in nematode Caenorhabditis elegans , evolving 35 lines parallel 409 generations three ( N = 1, 10, 100 individuals). Here, focus on nuclear SNPs small indels under minimal influence selection, as well their accrual larger populations greater selection efficacy. The base substitutions 1.84 × 10 −9 6.84 −10 changes /site/generation, respectively. Small exhibit deletion-bias with deletions exceeding insertions by three-fold. Notably, there was no correlation between frequency substitutions, nonsynonymous or size. These results contrast previous analysis mtDNA copy-number these MA lines, suggest that less stringent purifying compared to former mutational classes. A transition bias observed exons near universal substitution towards A/T. Strongly context-dependent where 5’–T 3’–As increase A/T → T/A transversions, especially boundaries T homopolymeric runs, manifest higher (i) introns intergenic regions relative exons, (ii) chromosomal cores versus arms tips, (iii) germline-expressed genes.