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Biology class analyzes dog DNA for body size, snout length and coat length

April 17, 2019
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By Diane Mar-Nicolle

Biological sciences senior lecturer Kathleen Fitzpatrick loves dogs and teaching, so it’s not surprising that she modified a genetics lab course to use dog DNA as the study subject.

Fitzpatrick teaches BISC 302, a research course that focuses on genetic analysis and how DNA helps us understand physical traits, certain behaviours, and impacts on health.

Using DNA taken from a swab supplied by canine “Fern,” students used sampling techniques to determine which of her genetic variants are associated with body size, snout length and coat length.

Before modifying the course, Fitzpatrick was using the fruit fly as a study subject, but found  students were not as engaged as she wanted them to be, so she replaced the fruit fly project with a dog project.

“Not surprisingly, many students have emotional connections with dogs and they found that topics like explaining the colour pattern of a dog’s coat were more interesting than the DMAP1 gene of the fruit fly,” laughs Fitzpatrick.

She explains that while most dogs have identical DNA, there are a huge number of variants associated with the features that make one dog physically different from another. For example, a Chihuahua and a Russian wolfhound share the majority of their genome, but a small number of variants gives them their diversity, such as tails that are either curly or straight and ears that are either floppy or upright.

Dog owner Sara taking a DNA swab from Fern's inner cheek.

Fitzpatrick explains that these genetic variants are not causative, and that associations with conditions, disorders or traits such as body size, snout length and coat length are only statistical associations.

To demonstrate the association of these traits, the students amplified small sections of DNA around seven variants and used enzymes that cut DNA in predictable places to digest the amplified segments. The students then separated the DNA segments by size, which revealed information about each dog’s genetic variations, based on their SNPs (single nucleotide polymorphisms).

Next came the hard work of explaining their results to a lay audience.

The students were tasked with writing up their findings as if they were presenting a professional report to the dog owner.

Because variants and associated traits are statistical and not causative Fitzpatrick says that it can be challenging to digest and explain them to a layperson.She says, “The variants the students studied are not influencing the physical characteristics of the dogs—they are found physically close to genes that are influencing the characteristics. The association between the variant and the trait will not be 100 per cent.”

Since using dogs as the study subject, Fitzpatrick finds her students seem to be more engaged in the course.

Third-year biology major Kirin Yaseen says, “BISC 302 has been an opportunity to learn real-life techniques and that has helped enhance my understanding of how genomics works in the world.”  

Breanna Handley, also a biology major in her third year, agrees.

“I thought this project was really interesting and engaging because a lot of us have dogs at home, so studying something that has real meaning to you really helps push you to do well.”

Fitzpatrick is happy with the course, but she’s not one to rest on her laurels.

“I'm always thinking about ways to tweak the experiments and improve the outcomes,” she says.

“My next hope is to pilot some kind of dog "paternity"-testing exercise. It will be like solving a mystery and if we get it working well, I think the students will find it interesting.”

Breanna Handley reviews her report with Fern's owner, Sara.