Cinnamon sticks to genetic map

The DNA of a four-year-old Abyssinian cat named Cinnamon, whose well-documented lineage can be traced back several generations to Sweden, has been sequenced.

Details of the assembly, annotation, and comparative analysis of the genome of Felis catus the domestic cat are published in the journal Genome Research

Cinnamon is one of several mammals that are currently being analysed using "light" (two-fold) genome sequence coverage.

To make sense of Cinnamon's raw sequence data, a multi-centre collaboration of scientists used information from previously sequenced mammalian genomes as well as previous gene-mapping studies in the cat.

They found that Cinnamon's sequences spanned about 65 per cent of the euchromatic regions of the feline genome.

The similarity between the cat genome and the other six recently completed mammalian genomes (human, chimpanzee, mouse, rat, dog, and cow) have allow the scientists to identify 20,285 putative genes in the cat genome.

The comparison also revealed hundreds of chromosomal rearrangements that have occurred among the different lineages of mammals since they diverged from a diminutive ancestor that roamed the earth among the dinosaurs some 100 million years ago.

The domestic cat serves as an excellent model for human disease, which is one reason why the US National Human Genome Research Institute (NHGRI) initially authorised the cat genome sequencing project three years ago.

Domestic cats possess over 250 naturally occurring hereditary disorders, many of which are similar to genetic pathologies in humans.

For example, Cinnamon's pedigree carries a genetic mutation that causes retinitis pigmentosa, a degenerative eye disease that can lead to blindness.

The domestic cat also serves as an excellent model for human infectious diseases, including HIV/AIDS. Feline immunodeficiency virus (FIV) is a genetic relative of human immunodeficiency virus (HIV), which causes AIDS.

Using the cat genome sequence data, the researchers identified several hundred thousand genomic which can be used to determine the genetic basis for common hereditary diseases.

Collaborators have already used these variants to identify the causative gene for Cinnamon's retinitis pigmentosa, publishing a paper in the May/June 2007 issue of the Journal of Heredity.

These variants will also be useful for parentage testing, forensic analysis, and studies of evolution, including the reconstruction of domestication processes, fancy breed development, and ecological adaptation among the great cats.

They also analysed the feline genome for interesting features such as microRNAs, Numts (pronounced "new mights"-nuclear genomic fragments that migrated to cat chromosomes from mitochondria), and a vast sea of selfish DNA-like repetitive elements.

According to her carers, Cinnamon is a shy cat. While the other cats in Dr Kristina Narfstrom's ophthalmology research centre at the University of Missouri College of Veterinary Medicine vie for the attention of veterinary medical students and technicians, Cinnamon is more reticent, preferring to sit quietly and watch the other cats play.

Narfstrom predicts that the feline genome will rapidly shed new research light on a number of cat and human medical problems including virus-mediated diseases, respiratory problems, cancers, AIDS, immunity problems, muscular dystrophy, polycystic kidney disorder, and Narfstrom's research specialty, retinal eye diseases.

Source: Genome Research/University of Missouri