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Deoxyribonucleic acid, abbreviated DNA, is the carrier of genes, and it contains all the genetic information and instructions that make up an organism, including information for development, growth, and reproduction. DNA is located in cells, mainly in the part of the cell called the nucleus (nuclear DNA), with a small amount found in the cell’s energy center called the mitochondria (mitochondrial DNA). Almost every cell in the body contains the same DNA, but humans and animals use different sets of DNA instructions leading to various cell types, including neurons, muscle cells, and blood cells. 

The structure of DNA is complex, where blocks of chemical substances called nucleotides are linked together like a long chain. A nucleotide consists of a sugar molecule attached to a phosphate group and a nitrogen-containing base. The bases present in DNA are adenine (A), cytosine (C), guanine (G), and thymine (T). These DNA bases create pairs, where A pairs with T, and C pairs with G. The order, or sequence, of these bases, is critical because it forms the instructions in the DNA. Each piece of DNA contains two long chains of nucleotides linked together by base pairs (like rungs of a ladder) to form the shape of a twisted ladder. 

When additional DNA is needed, for example, before a cell divides, DNA makes a photocopy of itself (known as DNA replication) to produce the DNA required for the new cell. During DNA replication, the two nucleotide chains of DNA separate (like breaking ladder) rungs, and each free nucleotide chain acts as a template for new chains of DNA.

As in humans, DNA in your pets comes from their parents. Half of the offspring’s DNA comes from the father and the other half from the mother. Therefore, the offspring may express characteristics of either parent or both. These characteristics may include the likelihood of developing certain diseases, such as cancer. Thus, understanding the science of DNA allows you to appreciate the makeup of your pet, their health risks, and how they can be treated if certain diseases arise.

The Pet Cancer Foundation’s Website Editorial team is comprised of veterinarians, veterinary oncologists, and veterinary technicians, as well as scientific writers and editors who have attained their PhD’s in the life sciences, along with general editors and research assistants. All content found in this section goes through an extensive process with multiple review stages, to ensure this extended resource provides pet families with the most up-to-date information publicly available.

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Last Updated: October 15, 2022

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The following sources were referenced to write the content on this page:

Read, CY 2017, ‘Primer in Genetics and Genomics, Article 3–Explaining human diversity: the role of DNA’, Biol Res Nurs, vol. 19, no. 3, pp. 350-356.

Alberts, B, 2003, ‘DNA replication and recombination’, Nature, vol. 421, no. 6921, pp. 431-435.

Binladen, J, Wiuf, C, Gilbert, MTP, Bunce, M, Barnett, R, Larson, G, Greenwood, AD, Haile, J, Ho, SYW, Hansen, AJ & Willerslev, E 2006. ‘Assessing the fidelity of ancient DNA sequences amplified from nuclear genes’, Genetics, vol. 172, no. 2, pp. 733-741.

The Pet Cancer Foundation’s medical resource for pet owners is protected by copyright.

For reprint requests, please see our Content Usage Policy.