Holocentric chromosomes

PLoS Genet. 2020 Jul 30;16(7):e1008918. doi: 10.1371/journal.pgen.1008918. eCollection 2020 Jul.

Abstract

Holocentric chromosomes possess multiple kinetochores along their length rather than the single centromere typical of other chromosomes [1]. They have been described for the first time in cytogenetic experiments dating from 1935 and, since this first observation, the term holocentric chromosome has referred to chromosomes that: i. lack the primary constriction corresponding to centromere observed in monocentric chromosomes [2]; ii. possess multiple kinetochores dispersed along the chromosomal axis so that microtubules bind to chromosomes along their entire length and move broadside to the pole from the metaphase plate [3]. These chromosomes are also termed holokinetic, because, during cell division, chromatids move apart in parallel and do not form the classical V-shaped figures typical of monocentric chromosomes [4-6]. Holocentric chromosomes evolved several times during both animal and plant evolution and are currently reported in about eight hundred diverse species, including plants, insects, arachnids and nematodes [7,8]. As a consequence of their diffuse kinetochores, holocentric chromosomes may stabilize chromosomal fragments favouring karyotype rearrangements [9,10]. However, holocentric chromosome may also present limitations to crossing over causing a restriction of the number of chiasma in bivalents [11] and may cause a restructuring of meiotic divisions resulting in an inverted meiosis [12].

MeSH terms

  • Animals
  • Caenorhabditis elegans / cytology
  • Caenorhabditis elegans / genetics*
  • Centromere / genetics
  • Centromere / ultrastructure
  • Chromatids / genetics
  • Chromatids / ultrastructure
  • Chromosome Segregation / genetics
  • Chromosomes / genetics*
  • Chromosomes / ultrastructure
  • Karyotype
  • Kinetochores / ultrastructure*
  • Meiosis / genetics*
  • Plants / genetics

Grants and funding

The authors received no specific funding for this work.