The database has been created and updated by scientists, technicians and librarians at the Institut Botànic de Barcelona, IBB-CSIC-ICUB : Ugo d’Ambrosio, Maria Pilar Alonso-Lifante, Karina Barros, Gemma Mas de Xaxars, María Luisa Gutiérrez, Roi Rodríguez González, Inés Fuentes, and Sònia Garcia with the collaboration of Francisco Gálvez-Prada (BioScripts) and Ales Kovarik from the Institute of Biophysics of the Academy of Sciences of the Czech Republic.

Main data sources

Jones, R. N., & Diez, M. 2004. The B chromosome database. Cytog. Gen. Res. 106: 149–150.

IPCN hard copies:

Goldblatt, P. & D. E. Johnson. 1998. Index to Plant Chromosome Numbers 1994–1995. Monogr. Syst. Bot. Missouri Bot. Gard. 69: 1–208.

Goldblatt, P. & D. E. Johnson. 2000. Index to Plant Chromosome Numbers 1996–1997. Monogr. Syst. Bot. Missouri Bot. Gard. 81: 1–188.

Goldblatt, P. & D. E. Johnson. 2003. Index to Plant Chromosome Numbers 1998–2000. Monogr. Syst. Bot. Missouri Bot. Gard. 94: 1–297.

Goldblatt, P. & D. E. Johnson. 2006. Index to Plant Chromosome Numbers 2001–2003. Monogr. Syst. Bot. Missouri Bot. Gard. 106: 1–242.

Goldblatt P, Johnson DE. 2010. Index to Plant Chromosome Numbers 2004–2006. In: Regnum Vegetabile Vol. 152. Goldblatt P, Johnson ED, eds. Ruggell: ARG Gartner Verlag, 256 pp.

Journal publications, books and meeting proceedings

Methodological approach

Publication search strategy

A search procedure was designed to retrieve scientific documents which included B chromosome counts. The databases used were Scopus, WOS (Web of Science), Scielo, DOAJ (Directory of Open Access Journals) and Google Scholar. Searches were performed using "B chromosome" as keyword. When the relevance of certain documents was not clear, we looked for the presence of other keywords such as "supernumerary chromosome", "accessory chromosome" or "selfish chromosome". During this process part of the initially recovered documents were discarded and as a result 3,292 articles, books and meeting proceedings were found to provide significant information on presence and/or number of Bs.

Data mining

The information was manually extracted from each source publication and when available (in most cases), the presence and number of Bs were visually checked in the pictures. Data was introduced in a Google Sheet and the following fields were filled for each entry: (1) kingdom, (2) phylum or (sub)division, (3) popular name of the containing group, (4) class, (5) order, (6) family, (7) genus, (8) specific epithet, (7) species name, (8) ploidy level, (9) somatic chromosome number (2n), (10) B-chromosomes, (11) complete citation reference in APA format, and (12) DOI or URL where the source publication is available. For plants, there was an additional category, (13) monocots or eudicots. Each entry and each publication had unique identification numbers. The information available from the work by Jones and Díez (2004) until 1994 and the IPCN compilations from years 1996-2006 were imported to the spreadsheet and formatted according to the mentioned structure.

How to use

B-chrom includes 6089 entries. Each entry is ascribed to a plant species, genus, family, order or class. The easiest way to use the database is by inserting the name of a genus or a species in the search box. The most represented groups in the database can also be selected from the Browse page.

Data on B-chromosomes is displayed as either: presence, with the letters “Bs”, specific number (e.g. 1, 2, 8) or a range (e.g. 2-6), depending on the information provided by the source publication. When the number of Bs referred to the gametic cells it was indicated with the letter “G” after the number of Bs. Also, when Bs where found either in male or in female individuals it was shown by the letters “m” and “f”, respectively. When the number of Bs was found at the haploid level we used the letter “n” (the case of some liverworts). Finally, the letters “PRS” indicate Paternal Sex Ratio, a type of Bs occurring in certain arthropods.

WARNING: Due to the search algorithm of the database, in cases of genera with short names (e.g. Mus) all taxa including the same word in their names (e.g. Apodemus peninsularis) may appear as a result of the query. In such cases, we recommend performing the Advance Search or any of the Browse options in which to select directly the genus or species of interest.

B-chrom database 2017