This is why I said that ****most**** relevant mutations have to be positive (because I am aware of neutral mutations).
No most mutations are not necessarily positive.
I haven’t read about this in the last 5 or so years.
But based on what I know combos of 2 neutral mutations is the most that have ever been observed and only in asexual microorganisms and under controlled conditions in the lab.
Not remotely true. Considering your very limited knowledge of the sciences of evolution it is understandable that you are very limited on what you know.
To define as per
population genetics,
neutral mutations are the mutations whose spread remains unaffected by the process of
natural selection. In other words, fixation of the neutral mutations is independent of natural selection. Since these mutations can escape the process of natural selection, these mutations accumulate and add to the variations in the
genetic pool or the
genetic drift. Genealogies or phylogenies are built or marked based on these neutral mutations.
Lifetime reproductive success, fecundity, longevity, viability, etc., are some of the life-history traits that determine the
fitness of the
genotype. Genetic alteration in these
traits critically determines the adaptability of an organism to its new environment. Accordingly, mutation can be deemed beneficial or harmful, and this also forms the basis of survival of the fittest.
Beneficial mutations are transferred to the next progeny as they become essential for survival. However, besides these harmful and beneficial mutations, there are a number of mutations that contribute to the variations in the genetic makeup of individuals. However, they have no phenotypic expression of these changes and do not alter the ability to survive and reproduce. Thus these mutations have been termed neutral mutations. Interestingly,
most mutations are neutral mutations. Neutral mutations also form the basis of the
neutral theory of molecular evolution and the
molecular clock.
Combos are very hard to obtain and are not expected to be very frequent.
But feel free to correct me
So far you have been rambling incorrectly without references or a specific meaningful argument.
Synonymous mutations can have highly variable fitness effects stemming from changes in transcription, some of which contribute to adaptation.
elifesciences.org
The fitness effects of synonymous mutations,
nucleotide changes that do not alter the encoded amino acid, have often been assumed to be neutral, but a growing body of evidence suggests otherwise. We used site-directed mutagenesis coupled with direct measures of competitive fitness to estimate the distribution of fitness effects among synonymous mutations for a gene under directional selection and capable of adapting via synonymous nucleotide changes. Synonymous mutations had highly variable fitness effects, both deleterious and beneficial, resembling those of nonsynonymous mutations in the same gene. This variation in fitness was underlain by changes in transcription linked to the creation of internal promoter sites. A positive correlation between fitness and the presence of synonymous substitutions across a phylogeny of related Pseudomonads suggests these mutations may be common in nature. Taken together, our results provide the most compelling evidence to date that synonymous mutations with non-neutral fitness effects may in fact be commonplace.
