Sunday 19 March 2006
Inversion refers to a rearrangement that involves two breaks within a single chromosome with inverted reincorporation of the segment. Inversions are often perfectly compatible with normal development.
An inversion involving only one arm of the chromosome is known as paracentric inversion. If the breaks are on opposite sides of the centromere, it is known as pericentric inversion.
The term was introduced by Sturtevant in 1926 for the reversal of the linear sequence of the genes in a segment of a chromosome. In an inversion heterozygote one of the chromosomes contributed by one parent has an inverted segment while the homologous chromosome contributed by the other parent has the normal gene sequence.