Inversions
In
an inversion chromosome a stretch of the chromosome is found in an inverse
orientation. This aberration does changes the order of genes. Sometime the
inversion break affects a gene. Inversion chromosomes are abbreviated as
In(3L)name The number indicates the chromosome Left (L) or Right (R) arm.Inversions mutations were first found as chromosomes that suppress recombination. Recombination occurs during meiosis and requires pairing of the homologous chromosomes. A chromosomal inversion affects recombination due to two properties
A) The pairing of the homologous chromosomes is not so easy and requires loop formation.
B) If pairing does occur and recombination takes place, the chromosomes will break during anaphase.
Inversions are one key element of the Balancer Chromosomes
Media list
Inversion, schematic (0.3 MB)