Inversion

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Introduction


Inversion are those structural change in chromosome , where a segment of a chromosome has a reverse order of genes relative to the normal order

It results when a segment of a chromosome is excised , inverted 180 degree reintegrated into the same chromosome

Inversion were discovered for the first time , when linkage studies were being undertaken in drosophila

Cytogenetic techniques may be able to detect inversion , or inversion may be inferred from genetic analysis


Types of inversion

Depending upon the position of breaks in chromosomes , there are two main types of inversion-

Paracentric inversion - an inversion of a segment of the chromosome that does not involve the centromeric region and the two breaks are in the same arm.

Pericentric inversion - an inversion of a segment of the chromosome that involves the centromeric region and the two breaks are in the different arm.

An inversion may be found on both the chromosome of a homologous pair or may restricted to one of the two chromosome ,so that the individual carrying it will be called inversion homozygote or inversion heterozygote respectively