From the source that follows:
… The fitness effects of
random mutations are relevant to
evolution in many ways. For
instance, they determine the fraction of nucleotide sites that evolves neutrally and thus
the rate at which populations diverge through
random genetic drift …
The Fitness Effects of Random Mutations in Single-Stranded DNA and RNA Bacteriophages
The Fitness Effects of Random Mutations in Single-Stranded DNA and RNA Bacteriophages
- Pilar Domingo-Calap,
- José M. Cuevas,
- Rafael Sanjuán
Abstract
Mutational fitness effects can be measured with relatively high accuracy in viruses due to their small genome size, which facilitates full-length sequencing and genetic manipulation. Previous work has shown that animal and plant RNA viruses are very sensitive to mutation. Here, we characterize mutational fitness effects in single-stranded (ss) DNA and ssRNA bacterial viruses. First, we performed a mutation-accumulation experiment in which we subjected three ssDNA (ΦX174, G4, F1) and three ssRNA phages (Qβ, MS2, and SP) to plaque-to-plaque transfers and chemical mutagenesis. Genome sequencing and growth assays indicated that the average fitness effect of the accumulated mutations was similar in the two groups. Second, we used site-directed mutagenesis to obtain 45 clones of ΦX174 and 42 clones of Qβ carrying random single-nucleotide substitutions and assayed them for fitness. In ΦX174, 20% of such mutations were lethal, whereas viable ones reduced fitness by 13% on average. In Qβ, these figures were 29% and 10%, respectively. It seems therefore that high mutational sensitivity is a general property of viruses with small genomes, including those infecting animals, plants, and bacteria. Mutational fitness effects are important for understanding processes of fitness decline, but also of neutral evolution and adaptation. As such, these findings can contribute to explain the evolution of ssDNA and ssRNA viruses.
Author Summary
The fitness effects of mutations are the raw material for natural selection. It has been shown that point mutations typically have strongly deleterious effects in plant and animal RNA viruses, whereas cellular organisms are comparatively more robust. Here, we characterize the fitness effects of random mutations in DNA viruses and compare them with those found in RNA viruses, using six phage species of similar genome sizes. To achieve this goal, we introduced mutations by chemical and site-directed mutagenesis, identified the genetic changes by sequencing, and quantified their fitness effects using growth-rate assays. In all cases, mutations had a strong average impact on fitness. We conclude that mutational sensitivity is a general property of viruses with small genomes and discuss the evolutionary implications of these findings.
No, you misrepresented epignetics, trasposons ,and natural genetics as I specifically referencesd by legitimate scientific references.
Again, again, and again . . .
What are the processes of evolution that are controversial not explained as natural pocesses in science, which are not accepted by 97%+ of all scientists in the fields of science related to evolution