D7S820

CODIS Core

D7S820 is a tetranucleotide short tandem repeat (STR) locus on chromosome 7 (7q21.11), one of the 20 CODIS core loci.

Basic Information

Chromosome

Cytogenetic Location

7q21.11

STRNaming template (FSSG)

A[n]CTAT[1]CAATCTGT[1]CTAT[n]_-1T>-

Type

Tetranucleotide

Alternative motifs (STRbase, historical notation)

[TATC]n rs7789995, [TATC]n rs7789995, rs16887642

Reference Allele

Explore internal sequence structure

See how the STRNaming name of the reference allele maps onto its sequence: repeat blocks, flanking regions and flanking variants.

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See the reads at this locus

Open the built-in IGV viewer on the hg38 window of this marker with a 1000 Genomes sample.

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Genomic Coordinates

GRCh38/hg38

Repeat region

chr7:84,160,226-84,160,277 (52 bp)

GRCh37/hg19

Repeat region

chr7:83,789,542-83,789,593 (52 bp)

Motif and sequences are shown on the forward (+) strand of GRCh38.

Sequence structure (FSSG)

ISFG minimum range, bracketing and kit coverage from the Forensic Sequence Structure Guide, FSSG v6.1 (STRidER; distributed as FSSG_v6-1_beta.xlsx).

STRNaming Formatted ISFG Minimum Range for Common Alleles (FSSG)

A[n]CTAT[1]CAATCTGT[1]CTAT[n]_-1T>-

A[8]CTAT[1]CAATCTGT[1]CTAT[n]

Reference allele (GRCh38) named with STRNaming 1.2.1

CE13_A[8]CTAT[1]CAATCTGT[1]CTAT[13]

Historical bracketing (2016-2023)

[TATC]13

ISFG minimum range (GRCh38)

chr7:84,160,200-84,160,281 (82 bp)

MPS kits covering this locus

PowerSeq 46GY
ForenSeq Signature Prep/Plus and MainstAY
Precision ID GlobalFiler NGS STR Panel v2 (Does not cover the whole ISFG minimum range.)
IDSeek OmniSTR Global

Kit range does not cover the whole ISFG minimum range of this locus (chr7:84,160,200-84,160,281), according to the kit ranges in the FSSG. Bases of the minimum range outside a kit's range are not sequenced by that kit; bases filled in from the reference should be identified as such.

Notes from the FSSG

Originally characterized on the reverse strand

Allele frequencies at a glance

Most common allele per population group, with its frequency and the sample size, in the capillary electrophoresis data of pop.STR / SP-SMART.

Africa: Allele 10 (0.405, n = 505)
Native American: Allele 10 (0.299, n = 537)
East Asia: Allele 11 (0.348, n = 221)
Central and South Asia: Allele 10 (0.246, n = 193)
Europe: Allele 10 (0.256, n = 659)
Middle East: Allele 10 (0.325, n = 157)
Oceania: Allele 11 (0.278, n = 18)

Allele frequencies by population group (pop.STR, CE). Alleles absent from every group are omitted.
Allele	AFR	NAM	EAS	CSA	EUR	MES	OCE
6	0.002	0	0	0	0	0	0
6.3	0	0.001	0	0	0	0	0
7	0.004	0.009	0	0.041	0.020	0.019	0
7.3	0.003	0	0	0	0	0	0
8	0.186	0.168	0.174	0.212	0.178	0.102	0.194
8.1	0.002	0	0	0	0	0	0
9	0.071	0.088	0.038	0.073	0.159	0.108	0.028
10	0.405	0.299	0.201	0.246	0.256	0.325	0.222
10.1	0.011	0	0	0	0	0	0
10.3	0.001	0.001	0	0	0	0	0
11	0.177	0.245	0.348	0.244	0.210	0.268	0.278
11.1	0.001	0	0	0	0	0	0
11.3	0.001	0	0	0	0	0	0
12	0.122	0.150	0.199	0.163	0.136	0.146	0.222
13	0.012	0.032	0.038	0.021	0.034	0.029	0.056
13.1	0	0.001	0	0	0	0	0
14	0.002	0.007	0	0	0.006	0.003	0
15	0	0.001	0	0	0	0	0

Allele frequencies by population group (pop.STR, CE). Alleles absent from every group are omitted.

Variant Alleles

STRbase reports 56 sequence variants across 19 allele designations.

6.3

7.3

8.1

9.1

9.2

9.3

10.1

10.3

11.1

11.3

Related markers

Other CODIS core loci

Browse the full STR marker catalog