Each F1 fish carries a unique set of heterozygous ENU-induced mutations, so any given mutation occurs only once in the entire library, i.e. at a ratio of 1 mutant: 18,048 WT alleles.
Under this assumption, for which each somatic mutation only happen once in the evolutionary history and not reverse mutation are allowed, subclonal cells can be identified and their prevalence estimated.
S9 and S10 (both compound heterozygotes for MCCC2 c.1015G>A mutation) had dissimilar genotypes in the proximal part of the interval but had three SNPs (spanning 5.5 kb) immediately proximal to the mutation and 21 SNPs (spanning ~800 Kb) distal to the mutation in which one allele was shared in common, suggesting the mutation arose only once in a distant ancestor.
For each solution in a set-based individual to be mutated, once its mutation reference point has been specified, its mutation direction is determined accordingly, and then the directional mutation can be performed according to the direction.
To address this question, Flint et al. [ 231, 233] proposed that the HbS mutation arose only once in Africa, and was transferred to other genetic backgrounds by means of gene conversion of short stretches assisted by a meiotic recombination hotspot (which, from a traditional perspective, just happens to be there).
Of the 10 BRCA1 mutations observed only once in our series, the c.1747A>T nonsense mutation is a novel gene alteration (not reported to the BIC by June 2004) found in family 397 with two cases of OC diagnosed at the ages of 39 and 43.
For somatic mutations reported only once in ccRCC or in other tumour types, only 38% of the high-risk mutations have been associated with VHL disease, compared with 18% of the low-risk mutations (P = 0.0132; Supplementary Material, Table S14).
Restricting attention to mutations detected only once in the sequencing effort would provide a measure of rarity, but an additional requirement that the variants be absent from a pool of 7,197 X chromosomal alleles served to further exclude low-frequency neutral alleles in favor of essentially private mutations.
Most of these mutations occurred only once in their study population.
These mutations only occur once in a great while, but evolution, as most know, is not a hurried process.
