Indicate what specific kinds of mutations would be most harmful to a population of organisms.

In humans, it is estimated that there are about 30 mutations per individual per generation, thus three in the functional part of the DNA. This implies that on the average there are about 3/2000 beneficial mutations per individual per generation and about 1.5 harmful mutations, Although mutation provides the ultimate source of genetic variation, it typically leads to decreased fitness. Even when a population is in the process of adaptation, the majority of its mutations are still deleterious and will ultimately be eliminated by selection, Harmful mutations may cause genetic disorders or cancer. A genetic disorder is a disease caused by a mutation in one or a few genes. A human example is cystic fibrosis. A mutation in a single gene causes the body to produce thick, sticky mucus that clogs the lungs and blocks ducts in digestive organs, Because an insertion or deletion results in a frame-shift that changes the reading of subsequent codons and, therefore, alters the entire amino acid sequence that follows the mutation, insertions and deletions are usually more harmful than a substitution in which only a single amino acid is altered.