This is the third release of the draft assembly of the Western lowland gorilla
Gorilla gorilla gorilla. The DNA sample came from a 30-year-old female,
Kamilah, owned by the San Diego Wild Animal Park,
and sequencing and assembly is provided by the
Wellcome Trust Sanger Institute.
Sequencing was undertaken using two separate methods: traditional capillary whole-genome shotgun (WGS) sequencing and Solexa new-technology sequencing. Results from the two methods were used in the first, second and third draft gorilla assemblies.
The first draft assembly (gorGor1) was released in September 2008. This initial draft assembly was a 2.1x coverage assembly. It was created from WGS capillary reads using the Phusion assembler, with these capillary reads' sequencing errors being corrected by taking the consensus of Solexa data aligned to it.
To create the second draft assemby, Solexa data, sequenced at roughly 35x, was assembled into contigs using Abyss. The resulting contigs of length 50bp or longer were then assembled along with the WGS capillary data using the Phusion assembler. Next, the Solexa read pairs were aligned to the human reference genome using Maq to identify syntenic regions and breakpoints between human and gorilla. Using human-gorilla synteny as a guide, longer gorilla supercontigs were constructed using Velvet and other assembly tools.
In the third draft assembly (gorGor3) for the current release, gorilla supercontigs which could be ordered with respect to the human reference genome were assembled into simulated chromosomes, while incorporating the chromosome 2 split (as in chimpanzee) and the reciprocal translocation between chromosomes 5 and 17.
The total length of the gorGor3 assembly is 3.04Gb. The N50 size for contigs is 11657 bp and the N50 size for supercontigs is 913458 bp.