Question

1. How does DNA methylation in some eukaryotes get inherited in progeny?

2. Why do disruptive DNA lesions, like deletions and insertions, sometimes not lead to frameshift mutation?

Answer 1

1.DNA methylation is stably inherited by offspring and spontaneous epialleles are rare. The majority of DNA methylations exhibit inheritance patterns that would be expected for local (cis) inheritance of DNA methylation variation such that DNA methylation level was coupled to local genotype.

2. Amino acid codons are made up of 3 nucleotides. Thus insertion or deletion of 3 nucleotides or multiples of 3 will leave the frame intact or the change will be minimum as inframe deletion will either delete one amino acid or inframe addition will add only one amino acid. So change will be not much in comparison to the change which will be brought by either the addition or deletion of 1 or 2 nucleotides.