The Cambridge Reference Sequence (CRS) for human mitochondrial DNA was first published in 1981^[1] leading to the initiation of the human genome project. ^[2]

A group under Dr. Fred Sanger at Cambridge University sequenced the mitochondrial genome of one individual of European descent during the 1970s, determining it to have a length of about 16,568 base pairs (0.0006% of the total human genome) containing some 37 genes.

When other researchers repeated the sequencing, some striking discrepancies were noted. The original published sequence included eleven errors, including one extra base pair in position 3107, and incorrect assignments of single base pairs. Some of these were the result of contamination with bovine and HeLa specimens. The corrected revised CRS mtDNA was published by Richard Andrews in 1999.^[3] (The original nucleotide numbering was retained to avoid confusion.) The reference sequence belongs to European haplogroup H2a2.

When mitochondrial DNA testing is used for genealogical purposes, the results are usually reported as differences from the revised CRS. Such differences are not necessarily mutations: the CRS is a reference sequence rather than a record of the earliest human mtDNA.

[edit] References

1. ^ S. Anderson et al., "Sequence and organization of the human mitochondrial genome, Nature, Vol. 290, 9 April 1981. pp. 457-465. http://www.mitomap.org/Anderson1981CRS.pdf
2. ^ The abbreviation "CRS" is also sometimes used to mean "coding region sequence".
3. ^ Richard M. Andrews et al., "Reanalysis and revision of the Cambridge reference sequence for human mitochondrial DNA", Nature Genetics, 23, 147, 1999. [1]

[edit] External links

• Human Mitochondrial DNA Revised Cambridge Reference Sequence (rCRS) at Mitomap.org
• An annotated revised Cambridge Reference Sequence (rCRS) at PhyloTree.org