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Deletion on a chromosome. In genetics, a deletion (also called gene deletion, deficiency, or deletion mutation) (sign: Δ) is a mutation (a genetic aberration) in which a part of a chromosome or a sequence of DNA is left out during DNA replication.
In genetics and especially genetic engineering, deletion mapping is a technique used to find out the mutation sites within a gene. The principle of deletion mapping involves crossing a strain which has a point mutation in a gene, with multiple strains who each carry a deletion in a different region of the same gene.
Indel (insertion-deletion) is a molecular biology term for an insertion or deletion of bases in the genome of an organism. Indels ≥ 50 bases in length are classified as structural variants. [1] [2] In coding regions of the genome, unless the length of an indel is a multiple of 3, it will produce a frameshift mutation.
Gene knockout by mutation is commonly carried out in bacteria. An early instance of the use of this technique in Escherichia coli was published in 1989 by Hamilton, et al. [2] In this experiment, two sequential recombinations were used to delete the gene.
Some mechanisms that are thought to underlie genome streamlining include deletion bias and purifying selection. [1] Deletion bias is the phenomenon in bacterial genomes where the rate of DNA loss is naturally higher than the rate of DNA acquisition. [2] [7] This is a passive process that simply results from the difference in these two rates. [7]
Biological illustrations can be found in use in history and anatomy textbooks, nature guides, natural history museums, scientific magazines and journals, botanical gardens, zoos and aquariums, surgical training manuals, and many more applications. Biological illustration can be pursued as a degree in the undergraduate, graduate, and technical ...
This theory implies that purifying selection is more efficient in the haploid stage of the life cycle where fitness effects are more fully expressed than in the diploid stage of the life cycle. Evidence supporting the masking theory has been reported in the single-celled yeast Saccharomyces cerevisiae . [ 8 ]
Devolution, de-evolution, or backward evolution (not to be confused with dysgenics) is the notion that species can revert to supposedly more primitive forms over time. The concept relates to the idea that evolution has a divine purpose and is thus progressive (orthogenesis), for example that feet might be better than hooves, or lungs than gills.