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Three major single-chromosome mutations: deletion (1), duplication (2) and inversion (3). In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. [ 1 ] Viral genomes contain either DNA or RNA.
When point mutations to just one base-pair of the DNA fall within a region coding for a protein, they are characterized by whether they are synonymous (do not change the amino acid sequence) or non-synonymous. Other types of mutations modify larger segments of DNA and can cause duplications, insertions, deletions, inversions, and translocations.
The human germline mutation rate is approximately 0.5×10 −9 per basepair per year. [ 1 ] In genetics, the mutation rate is the frequency of new mutations in a single gene, nucleotide sequence, or organism over time. [ 2 ] Mutation rates are not constant and are not limited to a single type of mutation; there are many different types of ...
Human genetic variation. A graphical representation of the typical human karyotype. The human mitochondrial DNA. Human genetic variation is the genetic differences in and among populations. There may be multiple variants of any given gene in the human population (alleles), a situation called polymorphism. No two humans are genetically identical.
The human genome is a complete set of nucleic acid sequences for humans, encoded as the DNA within each of the 24 distinct chromosomes in the cell nucleus. A small DNA molecule is found within individual mitochondria. These are usually treated separately as the nuclear genome and the mitochondrial genome. [ 1 ]
Examples of notable mutations that can occur in humans [35] During the process of DNA replication , errors occasionally occur in the polymerization of the second strand. These errors, mutations , can affect an organism's phenotype , especially if they occur within the protein coding sequence of a gene.
DNA may be modified, either naturally or artificially, by a number of physical, chemical and biological agents, resulting in mutations. Hermann Muller found that "high temperatures" have the ability to mutate genes in the early 1920s, [2] and in 1927, demonstrated a causal link to mutation upon experimenting with an x-ray machine, noting phylogenetic changes when irradiating fruit flies with ...
A distinct group of DNA-binding proteins is the DNA-binding proteins that specifically bind single-stranded DNA. In humans, replication protein A is the best-understood member of this family and is used in processes where the double helix is separated, including DNA replication, recombination, and DNA repair. [ 123 ]