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. 2022 May 19;11:ELIXIR-231. Originally published 2022 Feb 24. [Version 2] doi: 10.12688/f1000research.109080.2

Table 1. Summary of recommendations for metadata formatting.

Metadata field Definition Format Example Cardinality
##fileDate Creation date of the VCF file Date (ISO 8601, YYYYMMDD) ##fileDate=20120921 1
##bioinformatics_source Chains of bioinformatics tools for creating the VCF file URL, DOI ##bioinformatics_source=“ doi.org/10.1038/s41588-018-0266-x 1
##reference_ac Accession number of reference genome assembly used in the VCF file /[(GCA/GCF)_(d){9}\.(0-9)*]/ ##reference_ac=GCA_902498975.1 1
##reference_url URL of the reference genome assembly used in the VCF file URL, DOI ##reference_url=“ ftp.ncbi.nlm.nih.gov/genomes/all/GCA/902/498/975/GCA_902498975.1_Morex_v2.0/GCA_902498975.1_Morex_v2.0_genomic.fna.gz 1
##contig Metadata about a single sequence in the reference genome assembly Composite (see below) ##contig=<ID=chr1H,length=522466905,assembly=GCA_902498975.1,md5=8d21a35cc68340ecf40e2a8dec9428fa,species=NCBITaxon:4513> 1:N
The primary identifier of the sequence String ID=chr1H 1
The length in base pairs (bp) of the sequence Integer length=522466905 1
The assembly accession number this sequence belongs to /[(GCA/GCF)_(d){9}\.(0-9)*]/ assembly=GCA_902498975.1 1
The md5 checksum of the sequence MD5 md5=8d21a35cc68340ecf40e2a8dec9428fa 1
The species of the sequence (NCBI Taxon ID) /[(NCBITaxon):(\d+)]/ species=NCBITaxon:4513 1
##SAMPLE Metadata about a single sample genotype that is part of the genotyping experiment in the VCF file Composite (see below) ##SAMPLE=<ID=SAMEA104646767,DOI=“ doi.org/10.25642/IPK/GBIS/7811152”> 1:N
The primary identifier (BioSamples Database identifier) of the genotyping sample /[(SAM)(E|N|D)(A|G)(\d+)]/ ID=SAMEA104646767 1
The DOI of the genotyping sample (if available) URL, DOI DOI=“ doi.org/10.25642/IPK/GBIS/7811152 0-1
The external identifiers under which this genotyping sample is registered in other databases (either ‘FAO-WIEWS_instcode:genus:accession_number’ or ‘DNS:database_identifier:identifier_scheme:identifier’) See Definition ext_ID=“DEU146:Hordeum:HOR 1361 BRG” or ext_ID=“ipk-gatersleben.de:GBIS:akzessionId:7811152” 0:N