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Chromosomal reciprocal translocation of the 4th and 20th chromosome. In genetics, chromosome translocation is a phenomenon that results in unusual rearrangement of chromosomes. This includes balanced and unbalanced translocation, with two main types: reciprocal, and Robertsonian translocation.
Balancer chromosomes were first used in the fruit fly by Hermann Muller, who pioneered the use of radiation for organismal mutagenesis. [2]In the modern usage of balancer chromosomes, random mutations are first induced by exposing living organisms with otherwise normal chromosomes to substances which cause DNA damage; in flies and nematodes, this usually occurs by feeding larvae ethyl ...
Robertsonian translocation occurs in acrocentric chromosome pairs (number II in the image), where the short arms are fairly short but not very short. A: Short arm (p arm) B: Centromere C: Long arm (q arm) D: Sister chromatids. All chromosomes in animals have a long arm (known as q) and a short arm (known as p), separated by a region called the ...
This allowed chromosome pairs of otherwise equal size to be differentiated by distinct horizontal banding patterns. Banding patterns are now used to elucidate the breakpoints and constituent chromosomes involved in chromosome translocations. Deletions and inversions within an individual chromosome can also be identified and described more ...
Possessing chromosomes of varying shapes is generally the result of a chromosomal translocation or chromosomal inversion. In a translocation, genetic material is transferred from one chromosome to another, either symmetrically or asymmetrically (a Robertsonian translocation). In an inversion, a segment of a chromosome is flipped end-for-end.
Translocation can be an effective management strategy and important topic in conservation biology, but despite their popularity, translocations are a highâcost endeavor with a history of failures. [ 3 ] [ 4 ] It may decrease the risk of extinction by increasing the range of a species, augmenting the numbers in a critical population, or ...
In evolutionary biology, a balanced lethal system is a situation where recessive lethal alleles are present on two homologous chromosomes. [1] Each of the chromosomes in such a pair carries a different lethal allele, which is compensated for by the functioning allele on the other chromosome. [ 1 ]
Trisomy 21 – Down syndrome, an example of a polysomy at chromosome 21. Polysomy is a condition found in many species, including fungi, plants, insects, and mammals, in which an organism has at least one more chromosome than normal, i.e., there may be three or more copies of the chromosome rather than the expected two copies. [1]