rCRS
Definition
The revised Cambridge Reference Sequence (GenBank accession NC_012920), the standard reference for human mitochondrial DNA. All mtDNA variant positions in forensic and clinical reports are numbered relative to the rCRS. It replaced the original Cambridge Reference Sequence (cRS) in 1999 after resequencing identified a small number of errors and an A-to-C change at position 263.
- Length
- 16,569 base pairs
- GenBank Accession
- NC_012920
- Adopted
- 1999
- Required By
- ISFG, ENFSI, and EMPOP standards
Common questions
What is rCRS and why do forensic labs use it?+
rCRS is the Revised Cambridge Reference Sequence, the standard 16,569-base-pair human mitochondrial DNA sequence adopted in 1999. Forensic labs use it as a universal benchmark so that when they find a mtDNA variant, they can report it as a difference from rCRS positions. This standardization across labs makes results comparable and reproducible.
How is rCRS different from the original Cambridge Reference Sequence?+
The rCRS replaced the original 1981 Anderson sequence after resequencing in 1999 found errors and an A-to-C change at position 263. It corrected those mistakes and is now the mandatory reference for forensic and clinical mtDNA reporting under international standards like ISFG and ENFSI.
What does it mean when a forensic report says 'differences from rCRS'?+
Instead of listing the entire mtDNA sequence, labs report only the positions where the person's mtDNA differs from the rCRS template. For each difference, they note the position number and the base found there. This makes reports concise and standardized across all forensic cases.
Related terms
- Heteroplasmy
- The co-existence of two or more mitochondrial DNA sequence variants within a single individual, arising from somatic mutation or incomplete segregation. Length...
- AFDIL
- Armed Forces DNA Identification Laboratory, at Dover Air Force Base, Delaware. The US military's central identification laboratory, responsible for mtDNA-based identification of...
- D-Loop
- The non-coding displacement-loop control region of the mitochondrial genome (~bp 16024-576 in the rCRS). Contains the origin of replication and the promoters,...
- E-Value (BLAST)
- The expected number of alignments as good as the query result that would occur by chance in a database of the given...
- EMPOP
- EMPOP mtDNA Population Database, maintained at the Institute of Legal Medicine, Innsbruck, Austria. Contains over 50,000 curated mtDNA sequences and uses phylogenetic...
- EMPOP SAM2
- The submission quality-assurance module used by the EMPOP database to screen incoming mtDNA sequences for phylogenetic inconsistencies, sequencing artefacts, and nomenclature errors....
- Haplogroup
- A monophyletic branch of the human mitochondrial (or Y-chromosome) phylogenetic tree defined by a set of derived mutations. Haplogroup assignment is the...
- Hypervariable Region (HV1, HV2)
- Two segments within the mitochondrial D-loop that accumulate sequence variation faster than the coding mitochondrial genome. HV1 spans positions 16024-16365; HV2 spans...
- INSDC
- International Nucleotide Sequence Database Collaboration, the three-way partnership between GenBank (NCBI/NLM, US), ENA (EMBL-EBI, UK/EU), and DDBJ (National Institute of Genetics, Japan)...
- Petrous Bone
- The petrous portion of the temporal bone, the densest bone in the human skull. Its dense hydroxyapatite matrix protects enclosed DNA from...
- Protamine
- Small arginine-rich proteins that replace histones in the nuclei of spermatozoa during spermatogenesis, producing a hyper-compacted chromatin structure approximately six times denser...
- RSRS
- Reconstructed Sapiens Reference Sequence (2012). A phylogenetically derived ancestral human mtDNA sequence used in academic population genetics but not in forensic casework...
Explained in these topics
- Mitochondrial DNA Sequencing on HV1/HV2 and the rCRS ReferenceRevised Cambridge Reference Sequence, the corrected 1999 version of the first complete human mtDNA sequence (GenBank NC_012920). All forensic mtDNA profiles ar...
- Sequence Alignment, BLAST, GenBank, Mitomap and EMPOPThe revised Cambridge Reference Sequence (GenBank accession NC_012920), the standard reference for human mitochondrial DNA. All mtDNA variant positions in fore...
- The Cell, the Nucleus and the Mitochondrion as DNA ReservoirsRevised Cambridge Reference Sequence; the 16,569-bp human mitochondrial reference sequence revised in 1999 from the original 1981 Anderson sequence. Forensic m...