anchor.diff:  
   === Eligibility criteria
   
  -Studies and associations are eligible for inclusion in the NHGRI GWAS catalog if they meet the following criteria:
  +Studies and associations are eligible for inclusion in the NHGRI-EBI GWAS Catalog if they meet the following criteria:
   
   * Include a primary GWAS analysis, defined as array-based genotyping and analysis of 100,000+ pre-QC SNPs selected to tag variation across the genome and without regard to gene content.
   * GWAS data from published studies which are incorporated into new GWAS analyses are eligible, provided they meet the other criteria.
  
positive.code: 
  For each identified SNP, we extract:
  
  * REPORTED GENE: Gene(s) reported by the author; "Intergenic" is used to denote a reported intergenic location (or lack of gene if it appeared that gene information was sought); “NR” is used to denote that no gene location information was reported.
  * STRONGEST SNP-RISK ALLELE: SNP(s) most strongly associated with trait + risk/effect allele (? for unknown risk allele). May also refer to a haplotype.
  * SNPS: Strongest SNP; If a haplotype is reported above, this field may include more than one rs number (multiple SNPs comprising the haplotype). Multiple SNPs may also be included if proxy SNPs are reported.
  * RISK ALLELE FREQUENCY: Reported risk/effect allele frequency associated with strongest SNP in controls (if not available among all controls, among the control group with the largest sample size). If the associated locus is a haplotype the haplotype frequency will be extracted.
  * P-VALUE: Reported p-value for strongest SNP risk allele. Note that p-values are rounded to 1 significant digit (for example, a published p- value of 4.8 x 10-7 is rounded to 5 x 10-7).
  * PVALUE_MLOG: -log(p-value)
  * P-VALUE (TEXT): Information describing context of p-value (e.g. females, smokers).
  * OR or BETA: Reported odds ratio or beta-coefficient associated with strongest SNP risk allele. Note that if an OR <1 is reported this is inverted, along with the reported allele, so that all ORs included in the Catalog are >1. Appropriate unit and increase/decrease are included for beta coefficients.
  * 95% CI (TEXT): Reported 95% confidence interval associated with strongest SNP risk allele, along with unit in the case of beta-coefficients. If 95% CIs are not published, we estimate these using the standard error, where available.
  
negative.code: 
  The ancestry is derived from the ancestry descriptors used in the publication. Country of recruitment is extracted if an author states the country of recruitment of the samples. It is not assumed from an ancestry identifier or from a cohort name. Where a country of recruitment but no ancestry is provided, published population demographic information, such as the https://www.cia.gov/library/publications/the-world-factbook/[CIA World Factbook] is consulted.
  
  ==== [[mapping]]Quality control and SNP mapping
  
  An automated pipeline adds additional SNP specific information associated with the rsID extracted. This information includes the SNP's base pair and cytogenetic location(s) in the current human genome reference assembly, mapped genes, mapped gene distance’s and positioning, and SNP function. This information is then used for queries of the search interface and in the production of the diagram. The pipeline also performs checks for consistency and missing information, such as SNP identifiers, existence of SNPs in dbSNP, validation of gene names and confirmation that the reported SNP and gene are in the same chromosomal region. This information is retrieved using the link:http://www.ensembl.org/info/docs/api/index.html[Ensembl API] and the source of the data is both Ensembl and NCBI.
  
  Additional information added by this pipeline. Capitalised titles correspond to column headings in tab delimited file:
  
  * REGION: Cytogenetic region associated with rs number.
  * CHR_ID: Chromosome number associated with rs number.
  * CHR_POS: +++Chromosomal position, in base pairs, associated with rs number.+++
  * MAPPED GENE(S): Gene(s) mapped to the strongest SNP. If the SNP is located within a gene, that gene is listed, with multiple overlapping genes separated by “;”. If the SNP is intergenic, the upstream and downstream genes are listed, separated by “-”.
  * UPSTREAM_GENE_ID: Entrez Gene ID for nearest upstream gene to rs number, if not within gene.
  * DOWNSTREAM_GENE_ID: Entrez Gene ID for nearest downstream gene to rs number, if not within gene.
  