Holocentric Chromosomes

Abstract

Holocentric chromosomes are distinguished by the structure of the kinetochore, which extends along the poleward face of the metaphase chromosome. Holocentric chromosomes, which are found in diverse clades across the eukaryotic tree of life, have many structural features in common with the more familiar monocentric chromosomes, including DNA sequences and proteins associated with the kinetochore, and telomeric sequences. However, the absence of a localized centromere provides an opportunity for holocentric chromosomes to undergo rapid rearrangements by fission, fusion, and translocation. Many such rearrangements would result in inviable gametes in monocentric chromosomes, but may be propagated in meiosis or mitosis in organisms with holocentric chromosomes. Understanding holocentric chromosomes is important to understanding chromosome behavior more generally as well as the evolution of biodiversity in a range of plants and animals that possess holocentric chromosomes.