Abstract
Mutations are the ultimate basis of evolution, yet their occurrence rate is known only for few species. We directly estimated the spontaneous mutation rate and the mutational spectrum in the nonbiting midge C. riparius with a new approach. Individuals from ten mutation accumulation lines over five generations were deep genome sequenced to count de novo mutations that were not present in a pool of F1 individuals, representing parental genotypes. We identified 51 new single site mutations of which 25 were insertions or deletions and 26 single nucleotide mutations. This shift in the mutational spectrum compared to other organisms was explained by the high A/T content of the species. We estimated a haploid mutation rate of 2.1 × 10−9 (95% confidence interval: 1.4 × 10−9 – 3.1 × 10‐9) that is in the range of recent estimates for other insects and supports the drift barrier hypothesis. We show that accurate mutation rate estimation from a high number of observed mutations is feasible with moderate effort even for nonmodel species.
Highlights
Being the ultimate source of genetic variation for evolution to act upon, mutation is certainly among the most important evolutionary processes
The per generation rate at which spontaneous mutations occur in the genome is the central parameter to estimate the effective population size on recent time scales (Charlesworth 2009) or in the course of population history (Schiffels and Durbin 2014), equilibrium of genomic base composition (Hiroshi Akashi and Eyre-Walker 2012) and divergence times (Ho 2014)
Mutation rates should scale with effective population sizes (Lynch et al 2016)
Summary
Being the ultimate source of genetic variation for evolution to act upon, mutation is certainly among the most important evolutionary processes. Realized mutation rates are the result of random genetic drift setting a barrier to the effectiveness of selection improving the fidelity of replication. Mutation rates should scale with effective population sizes (Lynch et al 2016). There is a documented discrepancy between the many orders of magnitude of variation in population size and the much narrower distribution of diversity levels, originating from spontaneous mutations (Lewontin’s paradox, Ellegren and Galtier 2016). Would be highly desirable to shed light on the evolution of μ and its associated ecological and evolutionary circumstances (Lynch 2011). The understanding of μ variation among insects is not yet fully resolved (Liu et al 2016), and another direct rate estimate of a nonsocial insect species will help to increase resolution
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
