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As plants have evolved and adapted their UV coloration, pollinators have also fine-tuned their individual adaptations to maximize their ability to target flowers for food. [8] The dynamic relationship between the pollinators and the pollinated has led to novel mutations and in some cases novel species. [ 1 ]
The first is to avoid damaging mutations caused by UV radiation, as the nucleus stores the genetic material of a cell. A key problem faced as photosynthetic organisms transitioned from ocean to land was avoiding excessive mutations caused by UV radiation, but by moving the nucleus in response to light, damage caused by UV light could be limited.
UV-B resistance 8 (UVR8) also known as ultraviolet-B receptor UVR8 is an UV-B – sensing protein found in plants and possibly other sources. [2] It is responsible for sensing ultraviolet light in the range 280-315 nm and initiating the plant stress response. It is most sensitive at 285nm, near the lower limit of UVB.
Ds elements have shown to cause a 4.1kB and 2.0 kB insertions. [13] The transposable elements were seen in progeny of plants that had undergone stress, and mutations caused by the insertion are like those caused by x-rays, UV light, or chemicals causing events like chromosome breakage and fusion. [2]
Similarly, short wave UV light works in the same way as ionizing radiation which can also induce mutations generating chromosomal rearrangements. When DNA absorbs short wave UV light, dimerizing and oxidative mutations can occur which can cause severe damage to the DNA sequence of an organism.
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 ...
The middle portion of the coleoptile is the area where the shoot curvature occurs. The Cholodny–Went hypothesis, developed in the early 20th century, predicts that in the presence of asymmetric light, auxin will move towards the shaded side and promote elongation of the cells on that side to cause the plant to curve towards the light source. [5]
Illustration of chromosome crossover during genetic recombination. In evolutionary genetics, Muller's ratchet (named after Hermann Joseph Muller, by analogy with a ratchet effect) is a process which, in the absence of recombination (especially in an asexual population), results in an accumulation of irreversible deleterious mutations.