MutationsHemochromatosis is typically seen as an inherited disorder. Only under rare occasion is the disorder a result of an environmental mutation in which neither of the parents are carriers of the gene. As rare as it is, a mutation had to have occurred for the first person to ever have hemochromatosis. How might this have happened? What does it look like?
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Gene Mutatons
Gene mutations occur because of errors that happened during the duplication of DNA. There are many types of mutations that can occur, each has a different result on the order of genetic material. Based on they type of mutation, material may be reordered, changed, added, or taken away. The implications of these mutations can have large and disastrous effects. Since protein synthesis (noted in earlier sections) creates vital chemicals/molecules based on the order of the DNA in the individual, when this order is changed or altered, the proteins your body needs may never be created in the first place. Hemochromatosis is a disorder that affects the body's ability to create proper iron level detecting proteins that exist within the blood. When the gene or portion of the DNA that codes for this specific protein is altered, it may not be created at all or is formed the wrong way. Mutations can leave an individual without an important protein, causing hemochromatosis. The types of gene mutations are shown below.
For the following mutations, a sample genetic code will be used. The code is a made-up portion of the HFE gene after the DNA has been copied to RNA for protein synthesis. The HFE gene can code for hemochromatosis if it is mutated.
Important Vocabulary:
Missense Mutation: substituting one amino acid for another in a protein
Nonsense Mutation: signals a premature stop in the creation of a protein
Frameshift Mutation: changes the grouping of the bases for each codon down the line, usually results in the protein being unusable,
Important Vocabulary:
Missense Mutation: substituting one amino acid for another in a protein
Nonsense Mutation: signals a premature stop in the creation of a protein
Frameshift Mutation: changes the grouping of the bases for each codon down the line, usually results in the protein being unusable,
Example Code: UUC CAG UAC ACG CAC
Insertion - Adds a base to the sequence.
New Code: UUC CAG UAC UAC GCA C
Important to Note: The U was added at the beginning of an amino acid, changing what that specific amino acid is. It also causes a frameshift, altering all of the amino acids to come. This insertion will likely render the eventual protein useless.
Deletion - Removes a base from the sequence.
New Code: UUC AGU ACA CGC AC
Important to Note: The C before the A was deleted, changing what that specific amino acid is. It also causes a frameshift, altering all of the amino acids to come. This deletion will likely render the eventual protein useless.
Duplication - Bases from the sequence are abnormally copied.
New Code: UUC CAG UAC ACG ACG CAC
Important to Note: A full amino acid was duplicated. This will cause a frameshift, but all of the original amino acids will be created, just with an extra one thrown in. This mutation may keep the protein usable.
Substitution - Replaces one base in the sequence with another.
New Code: UUC CAG UAG ACG CAC
Important to Note: The original C was replaced with a G. This does not create a frameshift but a nonsense mutation in this example. UAG is a codon that stops the production of amino acids for the protein. In some situations, the effects of substitution may not be as large and may only cause a missense mutation.
Inversion - Changes the order of a specific portion within the sequence.
New Code: UUC GAC UAC ACG CAC
Important to Note: The code for this specific amino acid was revered. This example is a missense mutation, but in other situations, it could be a nonsense or frameshift mutation. The amino acid this codon was supposed to create will no longer be made.
Insertion - Adds a base to the sequence.
New Code: UUC CAG UAC UAC GCA C
Important to Note: The U was added at the beginning of an amino acid, changing what that specific amino acid is. It also causes a frameshift, altering all of the amino acids to come. This insertion will likely render the eventual protein useless.
Deletion - Removes a base from the sequence.
New Code: UUC AGU ACA CGC AC
Important to Note: The C before the A was deleted, changing what that specific amino acid is. It also causes a frameshift, altering all of the amino acids to come. This deletion will likely render the eventual protein useless.
Duplication - Bases from the sequence are abnormally copied.
New Code: UUC CAG UAC ACG ACG CAC
Important to Note: A full amino acid was duplicated. This will cause a frameshift, but all of the original amino acids will be created, just with an extra one thrown in. This mutation may keep the protein usable.
Substitution - Replaces one base in the sequence with another.
New Code: UUC CAG UAG ACG CAC
Important to Note: The original C was replaced with a G. This does not create a frameshift but a nonsense mutation in this example. UAG is a codon that stops the production of amino acids for the protein. In some situations, the effects of substitution may not be as large and may only cause a missense mutation.
Inversion - Changes the order of a specific portion within the sequence.
New Code: UUC GAC UAC ACG CAC
Important to Note: The code for this specific amino acid was revered. This example is a missense mutation, but in other situations, it could be a nonsense or frameshift mutation. The amino acid this codon was supposed to create will no longer be made.
Chromosome MutationsMutations not only can occur on specific genes themselves, but can occur on whole chromosomes, switching and changing large amounts of genetic code.
Translocation: The rearrangement of parts between non-homologous chromosomes.
Example: Chromosome 4: UUA CUG, GCG, ACC Chromosome 20: GAG, UUG, GGA, GUU Result: Chromosome 4: UUA CUG, GGA, GUU Chromosome 20: GAG, UUG, GCG, ACC Important to Note: An entire portion of DNA was switched between 2 chromosomes. This can have disastrous effects as the normal coding of proteins will cease to exist once it hits this changed portion. The amino acids needed for the specific proteins will not be created and multiple proteins could cease to exist when this type of mutation occurs. This will likely have extreme, even deadly effects. |