Association is determined by calculating the difference in frequency of each marker in the dogs with the disease or trait versus dogs that do not have the disease or trait. Most have nothing to do with disease, but they serve as street signs ("markers") for navigating the dog genome. SNPs, or single nucleotide polymorphisms, represent single bases in the genome that are frequently mutated. The most recent dog SNP chip has over 170,000 SNPs (described in Vaysse et al. 2006).įor most genome-wide comparisons we use a canine "SNP chip", this is a method for reading over 100 thousand spots on the genome at one time. This can be fairly straightforward when studying genes that control appearance, however, it is much more difficult when studying dog disease or behavior ( Spady et al.
To find a mutation that controls or is associated with a trait, scientists usually compare the DNA of dogs that have the trait to those that do not. Most DNA sequences are known as non-coding DNA, which may play regulatory roles such as turning genes on or off, determining the quantity of each gene to produce, or directing the encoded messenger RNA where to go in the cell. In order to locate nucleotide sequences responsible for traits of interest, researchers have to comb through approximately 3 billion base pairs, the length of the canine genome. The sequence of the dog genome was published in 2005 ( Lindblad-Toh et al. Also shown on this page are close up pictures of DNA.
The following sequence is an example of a nucleotide sequence: GGAAACCTGGTATA. Genes can determine how your dog will develop from the color of his fur to his personality traits and, in some cases, the diseases your dog will be susceptible to.Īdapted from NHGRI Intramural Publication The term "canine genome" refers to the entire sequence of the dog genome including all the genes and the spaces in between.
Each gene has a specific code that is passed from parent to offspring. Proteins are needed for all of the key systems in the body such as the nervous system or the digestive system. Genes encode the necessary machinery for manufacturing proteins, which in turn make up the body's physical structure. For a given gene the code is a very precise a single mistake in the DNA sequence could have disastrous consequences for the health of your dog.Įach of the 78 chromosomes contains the codes for hundreds of genes. The sequence of each gene is called its "code." For example, the code from one gene may lead to proteins that add color to a hair shaft, the code from another gene produces enzymes to digest food, and a third gene will direct the formation of antibodies that fight diseases. Genes are defined by a unique sequence of nucleotides which can be as few as a hundred bases or as many as a million. Dogs have approximately three billion base pairs in each cell. The bases are paired in fixed units of adenine-thymine (A-T) and guanine-cytosine (G-C). All living organisms, including humans, use this four-letter code. Chromosomes are made of deoxyribonucleic acid (DNA), the "molecule of life".ĭNA is made up of small chemical building blocks called "nucleotides" or "bases," which come in four types: adenine (A), guanine (G), cytosine (C) and thymine (T). During conception, a dog gets one copy of each chromosome from each parent.
In dogs, 38 pairs of autosomes (non-sex chromosomes) can be found in every nucleus, for a total of 76 chromosomes plus the two sex chromosomes (X and Y) for a grand total of 78.
Canine Genome Summary What is the Canine Genome?Ī dog's body contains trillions of cells.