The supernumerary mostly dispensable B chromosomes are nuclear components of about 15% of eukaryotic phyla. For a long time, B chromosomes have been studied, generating an enormous bulk of knowledge, diluted in the vastness of the scientific literature. In order to provide better access to this information, we created B-chrom ( www.bchrom.csic.es ), an online database with comprehensive information on Bs for plants, animals, and fungi. It was released in 2017 and first updated in 2021, by adding 334 entries and 123 new species. Currently, the resource provides information for 2951 species coming from 3292 sources. During this time, the usefulness of this database has been proven by the number of visits (more than 207,000 since its release) and by the scientific community, having been cited in more than 60 publications until present. This chapter explains the database composition and tips on how to use it.

Bioscripts Centro de Investigación y Desarrollo de Recursos Científicos Sevilla Spain

Institut Botànic de Barcelona IBB Barcelona Catalonia Spain

Institute of Biophysics Academy of Sciences of the Czech Republic Brno Czech Republic

Parc de Recerca Biomèdica de Barcelona Barcelona Catalonia Spain

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Houben A (2017) B chromosomes - a matter of chromosome drive. Front Plant Sci 8:210. https://doi.org/10.3389/fpls.2017.00210 PubMed DOI PMC

Pokorna MJ, Reifova R (2021) Evolution of B chromosomes: from dispensable parasitic chromosomes to essential genomic players. Front Genet 12:727570. https://doi.org/10.3389/fgene.2021.727570

Jones RN, Rees H (1982) B chromosomes. Academic, London, UK, p 266

Martis MM, Klemme S, Banaei-Moghaddam AM et al (2012) Selfish supernumerary chromosome reveals its origin as a mosaic of host genome and organellar sequences. Proc Natl Acad Sci U S A 109:13343–13346. https://doi.org/10.1073/pnas.120423710 PubMed DOI PMC

Valente GT, Conte MA, Fantinatti BEA et al (2014) Origin and evolution of B chromosomes in the cichlid fish Astatotilapia latifasciata based on integrated genomic analyses. Mol Biol Evol 31:2061–2072. https://doi.org/10.1093/molbev/msu148 PubMed DOI

Sharbel TF, Green DM, Houben A (1998) B chromosome origin in the endemic New Zealand frog Leiopelma hochstetteri through sex chromosome evolution. Genome 41:14–22. https://doi.org/10.1139/g97-091 PubMed DOI

Yoshida K, Terai Y, Mizoiri S (2011) B chromosomes have a functional effect on female sex determination in Lake Victoria cichlid fishes. PLoS Genet 7:e1002203. https://doi.org/10.1371/journal.pgen.1002203 PubMed DOI PMC

Beukeboom LW (1994) Bewildering Bs - an impression of the 1st B-chromosome conference. Heredity 73:328–336. https://doi.org/10.1038/hdy.1994.140 DOI

d’Ambrosio U, Alonso-Lifante MP, Barros K et al (2017) B-chrom: a database on B-chromosomes of plants, animals and fungi. New Phytol 216:635–642.  https://doi.org/10.1111/nph.14723

Mandáková T, Schranz ME, Sharbel TF, Jong H, Lysak MA (2015) Karyotype evolution in apomictic Boechera and the origin of the aberrant chromosomes. Plant J 82:785–793. https://doi.org/10.1111/tpj.12849 PubMed DOI

Jones RN (1976) Genome organisation in higher plants. In: Pearson PL, Lewis KR (eds) Chromosomes today, vol 5. Wiley, Chichester, pp 117–130

Williams E, Barclay PC (1968) The effects of B-chromosomes on vigour and fertility in Dactylis hybrids. New Zeal J Bot 6:405–416 DOI

Holmes DS, Bougourd SM (1989) B-chromosome selection in Allium schoenoprasum I. Natural populations. Heredity 63:83–87 DOI

Coleman JJ, Rounsley SD, Rodriguez-Carres M et al (2009) The genome of Nectria haematococca: contribution of supernumerary chromosomes to gene expansion. PLoS Genet 5:e1000618. https://doi.org/10.1371/journal.pgen.1000618 PubMed DOI PMC

Dhar MK, Friebe B, Koul AK, Gill BS (2002) Origin of an apparent B chromosome by mutation, chromosome fragmentation and specific DNA sequence amplification. Chromosoma 111:332–340. https://doi.org/10.1007/s00412-002-0214-4 PubMed DOI

Leach CR, Houben A, Field B, Pistrick K, Demidov D, Timmis JN (2005) Molecular evidence for transcription of genes on a B chromosome in Crepis capillaris. Genetics 171:269–278. https://doi.org/10.1534/genetics.105.043273 PubMed DOI PMC

van Vugt JJFA, de Nooijer S, Stouthamer R, de Jong H (2005) NOR activity and repeat sequences of the paternal sex ratio chromosome of the parasitoid wasp Trichogramma kaykai. Chromosoma 114:410–419. https://doi.org/10.1007/s00412-005-0026-4 PubMed DOI

Jones RN, Díez M (2004) The B chromosome database. Cytogenet Genome Res 106:149–150. https://doi.org/10.1159/000079280 PubMed DOI

Goldblatt P, Johnson DE (1998) Index to plant chromosome numbers 1994–1995. Monog Syst Botan 69:1–208

Goldblatt P, Johnson DE (2000) Index to plant chromosome numbers 1996–1997. Monog Syst Botan 81:1–188

Goldblatt P, Johnson DE (2003) Index to plant chromosome numbers 1998–2000. Monog Syst Botan 94:1–297

Goldblatt P, Johnson DE (2006) Index to plant chromosome numbers 2001–2003. Monog Syst Botan 106:1–24

Goldblatt P, Johnson DE (2010) Index to plant chromosome numbers 2004–2006. In: Goldblatt P, Johnson DE (eds) Regnum vegetabile, vol 152. Gartner Verlag, Ruggell, p 256

Werren JH, Stouthamer R (2003) PSR (paternal sex ratio) chromosomes: the ultimate selfish genetic elements. Genetica 117:85–101. https://doi.org/10.1023/A:1022368700752 PubMed DOI

Ghigliotti L, Christiansen JS, Carlig E, Di Blasi D, Pisano E (2020) Latitudinal cline in chromosome numbers of ice cod A. glacialis (Gadidae) from Northeast Greenland. Genes 11:1515. https://doi.org/10.3390/genes11121515 PubMed DOI PMC

Davey JW, Catta-Preta CM, James S, Forrester S, Motta MCM, Ashton PD, Mottram JC (2021) Chromosomal assembly of the nuclear genome of the endosymbiont-bearing trypanosomatid. Angomonas deanei. G3-Genes Genom Genet 11:1–7. https://doi.org/10.1093/g3journal/jkaa018 DOI