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An inversion is a chromosome rearrangement in which a segment of a chromosome becomes inverted within its original position. An inversion occurs when a chromosome undergoes a two breaks within the chromosomal arm, and the segment between the two breaks inserts itself in the opposite direction in the same chromosome arm.
The classical example is the Drosophila w m4 (speak white-mottled-4) translocation.In this mutation, an inversion on the X chromosome placed the white gene next to pericentric heterochromatin, or a sequence of repeats that becomes heterochromatic. [3]
Inversion was first noted in 1822 by the French zoologist Étienne Geoffroy Saint-Hilaire, when he dissected a crayfish (an arthropod) and compared it with the vertebrate body plan. The idea was heavily criticised, but periodically resurfaced, and is now supported by some molecular embryologists.
480p is the shorthand name for a family of video display resolutions.The p stands for progressive scan, i.e. non-interlaced.The 480 denotes a vertical resolution of 480 pixels, usually with a horizontal resolution of 640 pixels and 4:3 aspect ratio (480 × 4 ⁄ 3 = 640) or a horizontal resolution of 854 (848 should be used for mod16 compatibility) [1] pixels for an approximate 16:9 aspect ...
A hypercentric or pericentric lens is a lens system where the entrance pupil is located in front of the lens, in the space where an object could be located. In a certain region, objects that are further away from the lens produce larger images than objects that are closer to the lens.
This is called circle inversion or plane inversion. The inversion taking any point P (other than O ) to its image P ' also takes P ' back to P , so the result of applying the same inversion twice is the identity transformation which makes it a self-inversion (i.e. an involution).
A dicentric chromosome is an abnormal chromosome with two centromeres.It is formed through the fusion of two chromosome segments, each with a centromere, resulting in the loss of acentric fragments (lacking a centromere) and the formation of dicentric fragments. [1]
A breakage and reunion in the pericentric region of the p arm results in a dicentric isochromosome. [4] Some of the p arm can be found in this formation of i(Xq), but a majority of the genetic material on the p arm is lost so it is considered absent.