Question

Assume no natural selection, equal mutation rates across sexes and different chromosome types (X,Y, autosomes). Would you expect X chromosomes and autosomes to have different levels of per site neutral variations within species? What about between species?

Answer 1

There is a difference in population size, demography and mutation of sex chromosomes and autosomes, which largely affects the level of genetic variation and diversity within the genome of a species. Natural selection behaves exponentially on the two categories of the chromosomes, like, since the recessive mutations are straight away exposed to selection on the single X chromosome of males. different living organisms have different sex chromosome to autosome diversity ratio. Diminished recessive X chromosome variation reflects different demographic appearances, for example bottle necks and male biased dispersal. A considerable division of amino acid exchange between species are constructive. If these constructive mutations are semi recessive, then the rate of protein progression is quick for X linked genes as compared to the autosomal genes. While constructive mutations are the source for progressive adaptation for natural selection, the nature and behavior of this is not much known. For example, it is not clear whether the adaptations are principally done on freshly arising mutations or on the mutations that already exists or on a pool of selection balance.

The human Y chromosomes are only found in males and projects decreased levels of genetic diversity. For example if lesser males are involved in mating as compared to their counterpart female rates, fewer Y chromosome will be inherited. Also, natural selection might occur on mutations on the Y chromosome to decrease the genetic diversity. Since there are no reclinations across the Y chromosomes and each site is effectively linked on the Y chromosome to each other, therefore selection performed on any one site will indirectly affect the other sites on the Y chromosomes. The diversity on the Y chromosome is consistent with selections performed, thus eradicating the linked diversities, irrespective of positive selection occurring.

Genes associated with confinement between species appear to be unusually common on sex chromosomes. The sex-decisive site can be considered as a single locus on which both X and Y alleles create an equitable polymorphism, the classic coalescent theory for the effects of equitable polymorphisms at associated sites does not apply. That is due to the reason that irregular mating occurs between the X and Y alleles which significantly effects the recombination and the rates on which recombination occurs are different between the species. T