Question

Exlpain the following:

(a) Most genetic disorders that detrimentally affect survival or fertility are caused by recessive mutations. Discuss the reasons for this, in terms of both gene function and natural selection.

(b) However, there are some genetic disorders caused by dominant mutations. In light of your answers to part (a), how do these deleterious dominant mutations persist in a population?

Answer 1

Question.

Answer. Most genetic disorders that detrimentally affect survival or fertility are caused by recessive mutations because for a recessive mutation to be detrimental both the alleles of a gene has to be mutated to cause a particular disease. As natural selection favors those individual who fits into the given enviromrnt, therefore an individual who is having a recessive mutation might not survive till the age where that individual can reproduce and produce offsprings.

Question (b) Deleterious mutation might persists in a population in two ways

(i) That mutation has no effect on the reproduction ability of that organisms.

(ii) That mutation has a late onset and the orgnaisms has produced some offsprings and has already passed on the alleles for that gene. e.g. Huntington disease ( Autosomal Dominant).