Final answer:
SNPs are types of genetic variations where synonymous SNPs don't change the amino acid sequence of a protein, non-synonymous missense SNPs substitute a different amino acid which might alter protein function, and non-synonymous nonsense SNPs create a stop codon leading to premature protein termination.
Step-by-step explanation:
In genetics, single nucleotide polymorphisms (SNPs) are variations in a single nucleotide that occur at a specific position in the genome. There are different types of SNPs, each with distinct consequences for the function of genes and proteins.
Synonymous SNPs, also known as substitution or silent mutations, result in a nucleotide change that does not alter the amino acid sequence of the protein because of the redundancy of the genetic code. For example, if the codon GAA, which encodes for the amino acid glutamic acid, is changed to GAG, it still encodes for glutamic acid; thus, the resulting protein remains unchanged.
Non-synonymous missense SNPs result in a change in a single nucleotide that leads to the substitution of a different amino acid in the protein. This can affect the protein's function, which may lead to diseases such as sickle-cell anemia if the new amino acid has significantly different properties from the original.
Non-synonymous nonsense SNPs change a codon that normally encodes an amino acid into a stop codon. This leads to premature termination of protein synthesis, often resulting in a nonfunctional protein, as seen in conditions like β-thalassemia.