∞ generated and posted on 2020.12.17 ∞
Physical loss of nucleotides without replacement from genetic material.
| A Deletion mutation involves loss of nucleotides without loss of continuity of the nucleic acid molecule. |
Deletions are a type of mutation. Whether from genes or, more generally, from chromosomes, deletions create genetic though not physical gaps in DNA (or, for RNA viruses, in RNA).
These gaps are noticeable particularly upon comparison with related base sequences, either from ancestral organisms (e.g., parental strains) or from different but similar organisms (e.g., related species).
Genetic material that has been deleted is difficult to recover via mutation. Mutational reversions of deleted alleles thus tend not to happen.
Pseudoreversions, a.k.a., compensatory mutations, may still be possible, however, that is, mutations in different genetic material from that which has been deleted. Alternatively, genetic material that has been deleted may be replaced via recombination such as in association with horizontal gene transfer.
Given sufficient divergence of lineages prior to comparison, note that it can be difficult to distinguish between deletion of once shared genetic material in one species versus insertion of new genetic material in the other. Also difficult to see are shared deletions, that is, when both organisms possess the same or similar deletion.
Deletion mutations that are found in the middle of reading frames will tend to be less damaging to polypeptide gene product functioning if they are short, in nucleotide multiples of three, and found toward the end of genes.