Centric Fusion

Abstract

Different organisms have different sets of chromosomes. Changes in chromosome number, size, and morphology result from various rearrangements such as translocations, inversions, duplications, and centric or tandem fusions. Centric fusion is a very common evolutionary change in which there is a fusion of two nonhomologous chromosomes with terminal or near-terminal centromeres that produce bi-armed submetacentric or metacentric chromosomes. Centric fusions result in modifications to diploid number but do not influence the number of chromosome arms and are used in the karyotype evolution – not only in a large number of vertebrate species but also in insects and some plant species. Several examples are given. On the other hand, centric fusions, also called ‘Robertsonian translocations’, have severe clinical consequences in humans and economic importance in domestic animals. Detailed analysis of their causes and consequences is the substance of clinical cytogenetics.