Note: Released at UCSC April 22, 2022
This track contains mappings of single nucleotide variants
and small insertions and deletions (indels) — collectively Simple
Nucleotide Variants (SNVs) — from the European Variation Archive
Release 3 for the horse equCab3 genome. The dbSNP database at NCBI no longer
hosts non-human variants.
Interpreting and Configuring the Graphical Display
Variants are shown as single tick marks at most zoom levels.
When viewing the track at or near base-level resolution, the displayed
width of the SNP variant corresponds to the width of the variant in the
reference sequence. Insertions are indicated by a single tick mark displayed
between two nucleotides, single nucleotide polymorphisms are displayed as the
width of a single base, and multiple nucleotide variants are represented by a
block that spans two or more bases. The display is set to automatically collapse to
dense visibility when there are more than 100k variants in the window.
When the window size is more than 250k bp, the display is switched to density graph mode.
Searching, details, and filtering
Navigation to an individual variant can be accomplished by typing or copying
the variant identifier (rsID) or the genomic coordinates into the Position/Search box on the
A click on an item in the graphical display displays a page with data about
that variant. Data fields include the Reference and Alternate Alleles, the
class of the variant as reported by EVA, the source of the data, the amino acid
change, if any, and the functional class as determined by UCSC's Variant Annotation
Variants can be filtered using the track controls to show subsets of the
data by either EVA Sequence Ontology (SO) term, UCSC-generated functional effect, or
by color, which bins the UCSC functional effects into general classes.
Mousing over an item shows the ucscClass, which is the consequence according to the
Variant Annotation Integrator, and
the aaChange when one is available, which is the change in amino acid in HGVS.p
terms. Items may have multiple ucscClasses, which will all be shown in the mouse-over
in a comma-separated list. Likewise, multiple HGVS.p terms may be shown for each rsID
separated by spaces describing all possible AA changes.
Multiple items may appear due to different variant predictions on multiple gene transcripts.
For all organisms the gene models used were ncbiRefSeqCurated, except for mm39 which
Variants are colored according to the most potentially deleterious functional effect prediction
according to the Variant Annotation Integrator. Specific bins can be seen in the Methods section
|Protein-altering variants and splice site variants|
|Synonymous codon variants|
|Non-coding transcript or Untranslated Region (UTR) variants|
|Intergenic and intronic variants|
Sequence ontology (SO)
Variants are classified by EVA into one of the following sequence ontology terms:
- substitution —
A single nucleotide in the reference is replaced by another, alternate allele
- deletion —
One or more nucleotides is deleted. The representation in the database is to
display one additional nucleotide in both the Reference field (Ref) and the
Alternate Allele field (Alt). E.g. a variant that is a deletion of an A
maybe be represented as Ref = GA and Alt = G.
- insertion —
One or more nucleotides is inserted. The representation in the database is to
display one additional nucleotide in both the Reference field (Ref) and the
Alternate Allele field (Alt). E.g. a variant that is an insertion of a T maybe
be represented as Ref = G and Alt = GT
- delins —
Similar to tandemRepeat, in that the runs of Ref and Alt Alleles are of
different length, except that there is more than one type of nucleotide,
e.g., Ref = CCAAAAACAAAAACA, Alt = ACAAAAAC.
- multipleNucleotideVariant —
More than one nucleotide is substituted by an equal number of different
nucleotides, e.g., Ref = AA, Alt = GC.
- sequence alteration —
A parent term meant to signify a deviation from another sequence. Can be
assigned to variants that have not been characterized yet.
Data were downloaded from the European Variation Archive EVA release 3 (2022-02-24)
current_ids.vcf.gz files corresponding to the proper assembly.
Chromosome names were converted to UCSC-style, a few problematic variants were removed,
and the variants passed through the
Variant Annotation Integrator to
predict consequence. For every organism the ncbiRefSeqCurated gene models were used to
predict the consequences, except for mm39 which used the ncbiRefSeqSelect models.
Variants were then colored according to their predicted consequence in the following fashion:
- Protein-altering variants and
splice site variants
- exon_loss_variant, frameshift_variant,
inframe_deletion, inframe_insertion, initiator_codon_variant, missense_variant,
splice_acceptor_variant, splice_donor_variant, splice_region_variant, stop_gained,
stop_lost, coding_sequence_variant, transcript_ablation
- Synonymous codon variants
- synonymous_variant, stop_retained_variant
- Non-coding transcript or
Untranslated Region (UTR) variants
3_prime_UTR_variant, complex_transcript_variant, non_coding_transcript_exon_variant
- Intergenic and intronic variants - upstream_gene_variant, downstream_gene_variant,
intron_variant, intergenic_variant, NMD_transcript_variant, no_sequence_alteration
Sequence Ontology ("SO:")
terms were converted to the variant classes, then the files were converted to BED,
and then bigBed format.
No functional annotations were provided by the EVA (e.g., missense, nonsense, etc).
These were computed using UCSC's Variant Annotation Integrator (Hinrichs, et al., 2016).
Amino-acid substitutions for missense variants are based
on RefSeq alignments of mRNA transcripts, which do not always match the amino acids
predicted from translating the genomic sequence. Therefore, in some instances, the
variant and the genomic nucleotide and associated amino acid may be reversed.
E.g., a Pro > Arg change from the perspective of the mRNA would be Arg > Pro from
the persepective the genomic sequence.
For complete documentation of the processing of these tracks, read the
EVA Release 3 MakeDoc.
The data can be explored interactively with the Table Browser,
or the Data Integrator. For automated analysis, the data may be
queried from our REST API. Please refer to our
mailing list archives
for questions, or our Data Access FAQ for more
For automated download and analysis, this annotation is stored in a bigBed file that
can be downloaded from our download server. The file for this track is called evaSnp.bb.
Individual regions or the whole genome annotation can be obtained using our tool
bigBedToBed which can be compiled from the source code or downloaded as a precompiled
binary for your system. Instructions for downloading source code and binaries can be found
The tool can also be used to obtain only features within a given range, e.g.
bigBedToBed https://hgdownload.soe.ucsc.edu/gbdb/equCab3/bbi/evaSnp.bb -chrom=chr21 -start=0 -end=100000000 stdout
This track was produced from the European
Variation Archive release 3 data. Consequences were predicted using UCSC's Variant Annotation
Integrator and NCBI's RefSeq gene models.
Cezard T, Cunningham F, Hunt SE, Koylass B, Kumar N, Saunders G, Shen A, Silva AF,
Tsukanov K, Venkataraman S et al. The European Variation Archive: a FAIR resource of genomic variation for all
species. Nucleic Acids Res. 2021 Oct 28:gkab960.
Epub ahead of print. PMID: 34718739. PMID: PMC8728205.
Hinrichs AS, Raney BJ, Speir ML, Rhead B, Casper J, Karolchik D, Kuhn RM, Rosenbloom KR, Zweig AS,
Haussler D, Kent WJ.
UCSC Data Integrator and Variant Annotation Integrator.
Bioinformatics. 2016 May 1;32(9):1430-2.
PMID: 26740527; PMC: