Sloth assembly and gene annotation

Hoffmann's two-toed sloth (Choloepus hoffmanni) is a species of sloth from Central and South America. The slow movements of this animal are an adaptation for surviving on a low-energy diet of leaves, and they have half the metabolic rate of a typical mammal of the same size.


This is the first release of the low-coverage 2.05X assembly of the two-toed sloth (Choloepus hoffmanni). The genome sequencing and assembly is provided by the Broad Institute.

The N50 size is the length such that 50% of the assembled genome lies in blocks of the N50 size or longer. The contigs have an N50 length of 2461 bp and 8.6 kb for supercontigs. The total number of bases in supercontigs is 2.34 Gb and in contigs is 1.95 Gb.

The project coordination and genome sequencing and assembly is provided by the Human Genome Sequencing Center at Baylor College of Medicine

Gene annotation

Owing to the fragmentary nature of this preliminary assembly, it was necessary to arrange some scaffolds into "gene-scaffold" super-structures, in order to present complete genes. There are 8139 such gene-scaffolds, with identifiers of the form "GeneScaffold_1".

Mammalian Genome Project

Choloepus hoffmanni is one of 24 mammals that will be sequenced as part of the Mammalian Genome Project, funded by the National Institutes of Health (NIH). A group of species were chosen to maximise the branch length of the evolutionary tree while representing the diversity of mammalian species. Low-coverage 2X assemblies will be produced for these mammals and used in alignments for cross-species comparison. The aim is to increase our understanding of functional elements, especially in the human genome.

More information

General information about this species can be found in Wikipedia.



AssemblychoHof1, Sep 2008
Base Pairs2,060,419,685
Golden Path Length2,467,493,193
Annotation methodProjection build
Genebuild startedNov 2008
Genebuild releasedFeb 2009
Genebuild last updated/patchedMay 2010
Database version95.1

Gene counts

Coding genes12,393
Gene transcripts16,102


Genscan gene predictions109,168

About this species