Somewhat parallel too and independent of the Human Genome Reference Model or Build is the mitochondrial Reference Build. This has a separate and more refined history due to the much smaller size (only 16,600 or so base-pairs). The mitochondrial reference build is not considered part of the main human genome build but added to analysis models used in the industry. The 24 chromosomes along with mtDNA form the primary 25 sequences in any reference model.
The main model in use now is the (revised) Cambridge Reference System (or rCRS). It was an update to the earlier CRS. Yoruba is often heard and was distributed with Build36 and very early-on Build37. It was a revision, much like happened on yDNA independently, that was based on a sequence more ancient in the phylogenetic tree. RSRS was the latest model and based on the root of the phylogenetic tree known at the time. But for some reason has never caught on. The root yDNA model was back ported into many analysis models coming out of University of California, Santa Cruz (UCSC) "hg" model series. They are also the only source of Yoruba models still available.
The models are so close that you can almost hand edit / calculate the transformation from one to the other. What is important to know, just like for the other primary chromosomes, is which model the VCF or listing of variants is based on. Especially if only given as position.
The main model in use now is the (revised) Cambridge Reference System (or rCRS). It was an update to the earlier CRS. Yoruba is often heard and was distributed with Build36 and very early-on Build37. It was a revision, much like happened on yDNA independently, that was based on a sequence more ancient in the phylogenetic tree. RSRS was the latest model and based on the root of the phylogenetic tree known at the time. But for some reason has never caught on. The root yDNA model was back ported into many analysis models coming out of University of California, Santa Cruz (UCSC) "hg" model series. They are also the only source of Yoruba models still available.
The models are so close that you can almost hand edit / calculate the transformation from one to the other. What is important to know, just like for the other primary chromosomes, is which model the VCF or listing of variants is based on. Especially if only given as position.
External References
- coming soon; early draft page