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1 maj 2019 · A deletion mutation can remove a single nucleotide, or entire sequences of nucleotides. Deletions are thought to occur when the enzyme that synthesizes new DNA slips on the template DNA strand, effectively missing a nucleotide. This enzyme, polymerase, must attach the template DNA nucleotides in its active site for DNA replication to occur.
Deletion mutations. In the top sequence three nucleotides comprising a single codon are deleted. This shortens the resulting protein product by one amino acid but does not affect the rest of its sequence. In the lower section, a single nucleotide is deleted.
For example, single-stranded DNA breaks are repaired primarily by Base Excision Repair, bulky DNA adducts, and crosslinks are repaired by Nucleotide Excision Repair, and smaller nucleotide mutations, such as alkylation are repaired by Mismatch Repair.
By definition, a mutation is a heritable change in DNA sequence. This can happen in several ways: substitution of a DNA base, insertion or deletion of one or more DNA bases, or by large-scale chromosomal rearrangements, the latter of which will not be considered here.
Insertion or Deletion: An insertion changes the number of DNA bases in a gene by adding a piece of DNA. A deletion removes a piece of DNA. Insertions or deletions may be small (one or a few base pairs within a gene) or large (an entire gene, several genes, or a large section of a chromosome).
Strand slippage can also lead to deletion mutations. A deletion mutation occurs when a wrinkle forms on the DNA template strand and subsequently causes a nucleotide to be omitted from the...
10 wrz 2024 · Frameshift mutations, in contrast, result from either the insertion of a new nucleotide into the DNA strand or the deletion of a pre-existing nucleotide. This can occur through transposons, toxins, mutagens, or viruses.
