What effect do most “point” mutations in the DNa sequence have on the phenotypes?
I would say most “point” mutations have no effect, as most of the DNA in our cell is non-coding (intronic DNA). However, if the DNA sequence in your case is that of a gene, and it falls within a coding exon you could end up with one of these scenarios: 1. The nucleotide mutated is in position 3 of the codon –> most of these mutations are silent because of the redundant nature of the genetic code ==> no phenotypic change. 2. The nucleotide mutated is not in position 3 and gives rise to a different amino acid in the coded protein, but the different amino acid is of the same nature of the original amino acid ==> no phenotypic change. 3. The nucleotide mutated is not in position 3 and gives rise to a different amino acid in the coded protein, AND the new amino acid is different in structure, charge and function from the original amino acid ==> point mutation in the protein coded by this gene, which most likely will result in loss of function. 4. The nucleotide mutated is not in position 3
