Substantial evidence of epidemiology suggests that nuclear susceptibility genes, if present, should be sustained by mutation-selection balance without heterozygote advantage.
Then, pathogenic but neutral or almost neutral genes in ancient environments could be fixed at a high frequency close to 1 by genetic drift (because the effective population size might be much smaller and the effects of genetic drift might be predominant in ancient times) and can be sustained by mutation-selection balance today.
Therefore, such genes, if sustained by mutation-selection balance, cannot be susceptibility genes but instead are PGs that decrease the risk and the severity of the disease.
Because SCZ must be sustained by mutation-selection balance without heterozygote advantage in the NGM and the mutation rates in the nuclear genome are much lower than in the mitochondrial genome [ 12- 14], the criterion is strong.
Thus we have the criterion for a susceptibility gene: (6) d < ν, where ν is defined as ν ≡ (1 − s p ) μ (1 − p ) s p.From the observation (A5), we can see that d≥ v implies s> s M for any SCZ-associated variant M which is sustained by mutation-selection balance.
Only nucleotides in regions whose alignments were sustained by compensatory mutations across the entire data set were considered as homologous.
Nucleotides in paired regions whose secondary structure was sustained by compensatory mutations across the entire data set were considered as homologous.
These results indicate that the specific bridging role of N255 between the switch II loop and N413 of alpha tubulin (see Figure 4), which likely cannot be sustained by the N255K mutation, is not required for tight microtubule attachment.
Studies thus concentrate on how diversity is generated and sustained by processes, such as mutation, recombination, lateral gene transfer, ecological pressures, and the like.
A proper process of selection, such as natural selection as it operates on genetic replicators, needs to be sustained by low rates of mutation that are simply impossible to achieve in the case of human cultural transmission.
In the particular case of P. aeruginosa chronic lung infection, it has been proposed that the proliferation of the hypermutators in the population infecting an individual patient may be sustained by their association (hitchhike) with mutations adaptive to growth in the lung [19], [20].
