Domestic cats enjoy an extensive veterinary medical surveillance which has described nearly 250 genetic diseases analogous to human disorders. Feline infectious agents offer powerful natural models of deadly human diseases, which include feline immunodeficiency virus, feline sarcoma virus and feline leukemia virus. A rich veterinary literature of feline disease pathogenesis and the demonstration of a highly conserved ancestral mammal genome organization make the cat genome annotation a highly informative resource that facilitates multifaceted research endeavors.
Here we report a preliminary annotation of the whole genome sequence of Cinnamon, a domestic cat living in Columbia (MO, USA), bisulfite sequencing of Boris, a male cat from St. Petersburg (Russia), and light 30× sequencing of Sylvester, a European wildcat progenitor of cat domestication. The annotation includes 21,865 protein-coding genes identified by a comparative approach, 217 loci of endogenous retrovirus-like elements, repetitive elements which comprise about 55.7% of the whole genome, 99,494 new SNVs, 8,355 new indels, 743,326 evolutionary constrained elements, and 3,182 microRNA homologues. The methylation sites study shows that 10.5% of cat genome cytosines are methylated. An assisted assembly of a European wildcat, Felis silvestris silvestris, was performed; variants between F. silvestris and F. catus genomes were derived and compared to F. catus.
The presented genome annotation extends beyond earlier ones by closing gaps of sequence that were unavoidable with previous low-coverage shotgun genome sequencing. The assembly and its annotation offer an important resource for connecting the rich veterinary and natural history of cats to genome discovery.
The genome of a female Abyssinian cat (“Cinnamon” who resides at the University of Missouri-Columbia, USA) was sequenced at 1.8 × and 3.0 × whole genome shotgun (WGS) coverage at Agencourt Inc. Fca-6.2, an additional 12 × coverage of 454 reads and BAC ends was sequenced, assembled with CABOG  and analysed at Washington University, St. Louis (USA) . Fca-6.2 is anchored to chromosome coordinates with two physical framework maps, a radiation hybrid map  and a short tandem repeat (STR) linkage map . Further, 1943 distinct sites identified in a recently built linkage map using a single nucleotide polymorphism (SNP) genotyping array including ≈60,000 SNPs from an Illumina custom cat genotyping array are also mapped to the assembly.
Here we present a genome browser, Genome Annotation Resource Fields — GARfield , which displays the Fca-6.2 assembly and included annotated genome features. In Table 1 we list the features of GARfield annotated in the cat genome assembly which are described and illustrated in the Additional file 1 of this Data Note. The genome features detected in Fca-6.2 include a merged list of 21,865 genes derived from a comparative gene identification strategy using BLAST alignments between gene exons of reference genome from eight reference mammalian gene maps (human, chimpanzee, macaque, dog, cow, horse, rat, and mouse) obtained from the Ensembl Gene 75 database . In addition, the whole genome methylation sites and a methylome bisulfite sequence pattern of cat whole blood cells is presented, previewing epigenetic profiling in important complex disease associations, including diseases with viral and neoplastic etiology.
Annotated cat genome features available as genome browser tracks for GARfield and UCSC genome browsers
V. Nuclear mitochondrial (Numt) pseudo gene fragments
VI. Evolutionary constrainedelements (ECE)
Tables S17, S18
VII. Feline endogenous retrovirus-like elements
Table S19; Figure S18
VIII. Methylation sites
X. Variants between F. silvestris and F. catus.
Approximately 55.7% of the cat genome is composed of repetitive elements of familiar classes (LINEs, SINEs, satellite DNA, LTRs and others). We report more than 25 novel families of complex tandem repeat elements in the cat genome uncovered by multiple repeat detection algorithms. We searched for STR-microsatellite loci useful in population and forensic applications. Putative PCR primers for 53,710 STR loci are annotated. We also mapped known feline endogenous retroviral loci (full length RD114, FeLV, FERV) and detected 125 kb of partial retroviral genome sequences dispersed across the cat genome. Nuclear mitochondrial (Numt) DNA pseudogenes derived from ancient transposition from cytoplasmic mitochondrial chromosomes to nuclear chromosomal positions comprise 176 kb in addition to the Lopez-Numt, a 7.8 kb element tandem-repeated 38–76 times on Chromosome D2 previously described in the 1.8× analysis of Cinnamon’s genome .
The earlier 3,078,438 feline single nucleotide variants (SNVs) [7, 8] from largely non-repetitive regions of the cat genome are supplemented with a new group of 99,494 newly annotated SNPs plus 8,355 detected indels. In addition, we performed an assisted assembly with a 40× Illumina SOLID DNA sequence coverage of Sylvester, a European wildcat, F. silvestris silvestris, a wild representative of the species from which cats were domesticated approximately 10,000 years ago . Genome variations (SNVs and indels) between F. silvestris and F. catus SNPs are reported here and both species’ genomes and their associated data have been uploaded to the GARfield genome browser (see Availability of supporting data section).
Our annotation resolved cat homologues of 743,362 evolutionarily constrained elements (ECEs) recently identified in the human genome by alignment to 29 different mammalian genomes  and these were compared to the conserved sequence blocks obtained by the reciprocal best match (RBM) screen for cat genes with seven mammalian genomes (human, chimp, macaque, dog, cow, rat and mouse). A conservative alignment approach implicated 54% of the human ECE sequence comprising ≈3% of the cat genome. A total of 3,182 feline microRNA (miRNA) homologues were detected and mapped based upon homology to miRNA sequences from 36 species with miRNA sequence described in the miRBase database . Finally we screened the genome sequence for copy number variation and segmental duplications. All annotated features listed in Table 1 are described in detail in Additional file 1 and tracked in the GARfield genome browser.
Sequence and variation data is available in NCBI (SAMN02795853 for Boris the cat and SAMN02898152 for wildcat) and supporting data is also available in the GigaDB repository .
Evolutionary constrained element
Single nucleotide polymorphism
Single nucleotide variant
Short tandem repeat.
The authors are grateful to Elena Savelyeva (Clinical Biochemistry Laboratory of St. Petersburg Academy of Veterinary Medicine) for preparing samples of Boris the cat. This work was supported, in part, by Russian Ministry of Science Mega-grant no.11.G34.31.0068; Stephen J. O’Brien, Principal Investigator and ERC Starting Grant (260372) and MICINN (Spain) BFU2011-28549 grants to Tomas Marques-Bonet.
Theodosius Dobzhansky Center for Genome Bioinformatics, St. Petersburg State University
Laboratory of Neurogenetics, NIAAA
CIIMAR — Interdisciplinary Centre of Marine and Environmental Research, University of Porto
Department of Animal and Food Science, Veterinary Molecular Genetics Service, Universitat Autónoma de Barcelona
IBE, Institute of Evolutionary Biology, Universitat Pompeu Fabra-CSIC, PRBB (The Barcelona Biomedical Research Park)
Department of Computer Engineering, Bilkent University
Laboratory of Genomic Diversity, Frederick National Laboratory for Cancer Research
Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri
Oceanographic Center, Nova Southeastern University
Miller JR, Delcher AL, Koren S, Venter E, Walenz BP, Brownley A, Johnson J, Li K, Mobarry C, Sutton G: Aggressive assembly of pyrosequencing reads with mates.Bioinformatics 2008,24(24):2818–2824. 10.1093/bioinformatics/btn548PubMed CentralPubMedView Article
Hubbard T, Barker D, Birney E, Cameron G, Chen Y, Clark L, Cox T, Cuff J, Curwen V, Down T, Durbin R, Eyras E, Gilbert J, Hammond M, Huminiecki L, Kasprzyk A, Lehvaslaiho H, Lijnzaad P, Melsopp C, Mongin E, Pettett R, Pocock M, Potter S, Rust A, Schmidt E, Searle S, Slater G, Smith J, Spooner W, Stabenau A, et al.: The Ensembl genome database project.Nucleic Acids Res 2002, 30:38–41. 10.1093/nar/30.1.38PubMed CentralPubMedView Article
Pontius JU, Mullikin JC, Smith DR, Lindblad-Toh K, Gnerre S, Clamp M, Chang J, Stephens R, Neelam B, Volfovsky N, Schäffer AA, Agarwala R, Narfström K, Murphy WJ, Giger U, Roca AL, Antunes A, Menotti-Raymond M, Yuhki N, Pecon-Slattery J, Johnson WE, Bourque G, Tesler G, O’Brien SJ, Agencourt Sequencing Team: Initial sequence and comparative analysis of the cat genome.Genome Res 2007,17(11):1675–1689. 10.1101/gr.6380007PubMed CentralPubMedView Article
Mullikin J, Hansen N, Shen L, Ebling H, Donahue W, Tao W, Saranga D, Brand A, Rubenfield M, Young A, Cruz P, Program NCS, Driscoll C, David V, Al-Murrani S, Locniskar M, Abrahamsen M, O’Brien S, Smith D, Brockman J: Light whole genome sequence for SNP discovery across domestic cat breeds.BMC Genomics 2010, 11:406. 10.1186/1471-2164-11-406PubMed CentralPubMedView Article
Driscoll CA, Menotti-Raymond M, Roca AL, Hupe K, Johnson WE, Geffen E, Harley EH, Delibes M, Pontier D, Kitchener AC, Yamaguchi N, O’Brien SJ, Macdonald DW: The near eastern origin of cat domestication.Science 2007,317(5837):519–523. 10.1126/science.1139518PubMedView Article
Lindblad-Toh K, Garber M, Zuk O, Lin M, Parker B, Washietl S, Kheradpour P, Ernst J, Jordan G, Mauceli E, Ward L, Lowe C, Holloway A, Clamp M, Gnerre S, Alföldi J, Beal K, Chang J, Clawson H, Cuff J, Di Palma F, Fitzgerald S, Flicek P, Guttman M, Hubisz M, Jaffe D, Jungreis I, Kent W, Kostka D, Lara M, et al.: A high-resolution map of human evolutionary constraint using 29 mammals.Nature 2011,478(7370):476–482. 10.1038/nature10530PubMed CentralPubMedView Article
Griffiths-Jones S, Grocock RJ, Van Dongen S, Bateman A, Enright AJ: miRBase: microRNA sequences, targets and gene nomenclature.Nucleic Acids Res 2006,34(suppl 1):D140-D144.PubMed CentralPubMedView Article
Tamazian G, Simonov S, Dobrynin P, Makunin A, Logachev A, Komissarov A, Shevchenko A, Brukhin V, Cherkasov N, Svitin A, Koepfli K, Pontius J, Driscoll CA, Blackistone K, Barr C, Goldman D, Antines A, Quilez J, Lorente-Galdos B, Alkan C, Marques-Bonet T, Menotti-Raymond M, David V, Narfström K, O’Brien SJ: Genomic data of the domestic cat (Felis catus). GigaSci Database 2014. http://dx.doi.org/10.5524/100098
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.