Anchor Summary
A mutation is a permanent change in genetic material that may be passed from the parent to offspring (child). They are the sources of genetic variety within populations and species. DNA encodes genetic information that specifies how proteins should be assembled. For example, there are many sequence of bases such as (A,C,T and G) in a gene spells out the order of amino acids in the protein. The mutation in DNA depends on the result in a different protein being made or no protein being made at all. Amino acids are represented by triplets of bases called codons. It is often found that a single amino acids may be presented by more than one codon. For example, the codons TTA and TTG both code for the amino acids leucine (LEU). Although this is true, the gene sequence would be different but the same protein would be made. This happens because the mutation does not cause a change in the protein, which would be called a silent mutation. If the second base in the same codo were to change to a C then the new codon specifies a different amino acid and when the protein is assembled the amino acid serine will be substituted for leucine. Then the “meaning” of codons changes, this type of mutation is know as a missense mutation. The stop codons tell the ribosome when it reaches the end of the gene sequence on a mRNA strand. A nonsense mutation is one that changes a codo into a stop mutation. Mutations have the ability to delete or insert nucleotides in a gene; if three or more bases are added or removed the number of codons slightly changes. However the number of inserted or deleted bases is not a multiple of three which is then called a frameshift mutation.
A mutation is a permanent change in genetic material that may be passed from the parent to offspring (child). They are the sources of genetic variety within populations and species. DNA encodes genetic information that specifies how proteins should be assembled. For example, there are many sequence of bases such as (A,C,T and G) in a gene spells out the order of amino acids in the protein. The mutation in DNA depends on the result in a different protein being made or no protein being made at all. Amino acids are represented by triplets of bases called codons. It is often found that a single amino acids may be presented by more than one codon. For example, the codons TTA and TTG both code for the amino acids leucine (LEU). Although this is true, the gene sequence would be different but the same protein would be made. This happens because the mutation does not cause a change in the protein, which would be called a silent mutation. If the second base in the same codo were to change to a C then the new codon specifies a different amino acid and when the protein is assembled the amino acid serine will be substituted for leucine. Then the “meaning” of codons changes, this type of mutation is know as a missense mutation. The stop codons tell the ribosome when it reaches the end of the gene sequence on a mRNA strand. A nonsense mutation is one that changes a codo into a stop mutation. Mutations have the ability to delete or insert nucleotides in a gene; if three or more bases are added or removed the number of codons slightly changes. However the number of inserted or deleted bases is not a multiple of three which is then called a frameshift mutation.