Special Issue "Evolution, Composition and Regulation of Supernumerary B Chromosomes"

A special issue of Genes (ISSN 2073-4425). This special issue belongs to the section "Population and Evolutionary Genetics and Genomics".

Deadline for manuscript submissions: 31 August 2018

Special Issue Editors

Guest Editor
Prof. Andreas Houben

Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben,Corrensstraße 3, 06466 Stadt Seeland, Germany
Website | E-Mail
Interests: chromosome structure; B chromosome; centromere; CENH3; genome evolution
Guest Editor
Prof. Neil Jones

Aberystwyth University, Institute of Biological, Environmental and Rural Sciences (IBERS), Edward Llwyd Building, Penglais Campus, Aberystwyth SY23 3DA, UK
Website | E-Mail
Phone: 44 (0)1970 622230
Interests: Plant cytogenetics; B chromosomes; genome evolution
Guest Editor
Prof. Cesar Martins

Department of Morphology, Institute of Biosciences, UNESP - São Paulo State University, 18618-689, Botucatu, SP, Brazil
Website | E-Mail
Interests: B chromosomes; genome evolution; evolution; comparative genomics
Guest Editor
Dr. Vladimir Trifonov

Institute of Molecular and Cellular Biology of the Siberian Branch of the Russian Academy of Sciences (IMCB SB RAS), 630090 Novosibirsk, Russia
Website | E-Mail
Interests: evolution of vertebrate genomes; sex determination and sex chromosomes; B chromosomes; comparative genomics

Special Issue Information

Dear Colleagues,

Supernumerary B chromosomes are dispensable genetic elements found in thousands of species of plants and animals, and some fungi. Since their discovery, more than a century ago, they have been a source of puzzlement, as they only occur in some members of a population and are absent from others. When they do occur, they are often harmful, and in the absence of 'selfishness', based on mechanisms of mitotic and meiotic drive, there appears to be no obvious reasons for their existence. Cytogeneticists have long wrestled with questions about the biological existence of these enigmatic B chromosomes, including their lack of any adaptive properties, apparent absence of functional genes, their origin, sequence organization and co-evolution as nuclear parasites. Emerging new technologies are now enabling researchers to step up a gear, to look enthusiastically beyond the previous limits of the horizon, and to uncover the secrets of these 'silent' elements. Detailed investigations into their DNA composition, transcriptional activity and effects on the host transcriptome profile are beginning to uncover a wealth of new information. Contributing authors come from across a wide range of species, and different systems, and their thematic output will give a broad view and a significant step forward to understanding this perplexing biological story.

Prof. Andreas Houben
Prof. Neil Jones
Prof. Cesar Martins
Dr. Vladimir Trifonov
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Genes is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.


  • accessory chromosome
  • B chromosome
  • supernumerary chromosome
  • selfish DNA
  • degeneration
  • chromosome drive
  • gene silencing
  • heterochromatization
  • Muller’s ratchet
  • mutation accumulation
  • pseudogenization
  • recombination
  • repetitive DNA
  • retrotransposons
  • pseudogene
  • evolution
  • karyotype
  • next generation sequencing
  • chromosome thripsis

Published Papers

This special issue is now open for submission, see below for planned papers.

Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Tentative title: Structural and functional analysis of transposable elements focusing on B chromosomes of the cichlid fish Astatotilapia latifasciata 

Authors: Rafael LB COAN and Cesar MARTINS

Authors affiliation: Sao Paulo State University (UNESP), Institute of Biosciences, Department of Morphology, Botucatu, SP, Brazil. 

Tentative abstract: B chromosomes (B) are supernumerary elements found in many taxonomic groups. Most B chromosomes are rich in heterochromatin and composed of abundant repetitive sequences, especially transposable elements (TE). Bs origin is generally linked to the A chromosome complement (A). The first report of a B chromosome in African cichlids was on Astatotilapia latifasciata, which can harbor 0, 1 or 2 B chromosomes. Classical cytogenetics studies found high TE content on the species B chromosome. In this study, we aim to understand TE composition and expression on A. latifasciata genome and its relation to the B chromosome. We use bioinformatics analysis to find TE organization on the genome, and also their composition on the B chromosome. Bioinformatics findings were validated by fluorescent in situ hybridization (FISH) and real-time PCR (qPCR). A latifasciata has a TE content similar to other cichlid fishes and several expanded elements on its B chromosome. With RNA sequencing data (RNA-seq) we showed that all major TE classes are transcribed in brain, muscle and male/female gonads. The evaluation of TE expression between B- and B+ individuals showed that few elements have differential expression among groups and expanded B elements were not highly transcribed. Putative silencing mechanisms may the acting on the B chromosome of A. latifasciata to prevent adverse consequences of repeat transcription and mobilization on the genome.


Tentative title: Transmission and drive involving parasitic B chromosomes

Author: Neil Jones

Tentative abstract: B chromosomes are enigmatic additional elements in the genomes of thousands of species of plants, animals and fungi. How do these non-essential, harmful and parasitic chromosomes maintain their presence in their hosts, making demands on all the essential functions of their host genomes? The answer seems to be that they have mechanisms of drive which enable them to enhance their transmission rates by various processes of non-Mendelian inheritance. These processes are reviewed and discussed.

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