Student retention is a recurring challenge in undergraduate science education. We address this issue for diverse life science cohorts taking an introductory lab course in genetics. Applying an anthropomorphic spin, we designed a mock-up experiment about the parallel evolution of humans and dogs. In humans, the gene AMY has been duplicated several times, resulting in a wide variation of gene copy numbers among individuals. In addition, while populations traditionally consuming low-starch food (ex.: hunter-gatherers) have, on average, low AMY copy numbers, populations that have integrated high-starch food for a long time possess, on average, high AMY copy numbers. As the AMY gene encodes for the protein amylase that breaks up starch into sugar, a high-energy nutrient of human diet, it has been proposed that a high AMY copy number would lead to an elevated production of salivary amylase and would confer a selective advantage through enhanced nutrition. For our mock-up experiment, students test whether similar selective pressures acted on dogs, which were domesticated by humans at least 10,000 years ago.

Students are presented with simulated amylase samples from 8 representative dog breeds and from a wild canid (gray wolf, Canis lupus). They perform a laboratory test (enzyme-linked immunosorbent assay or ELISA) to quantify the amount of amylase in their unknown canid samples (dogs or wolves). Once the quality of the processed samples and controls has been verified and approved by lab instructor, students get to know the identity of their sampled subjects (breed or species and AMY copy number). Then, all class samples are pooled to increase sample size and improve result validity. Using the class data, students test if the positive association between AMY copy number and amylase production observed in humans is also present in dogs, hence testing for a pattern of parallel evolution.

To date, the experiment has been performed for three years by three lab sections per year. Despite the limited experience (primarily second year students) and the high number of experimenters (approximately 50-60 per year), a positive association between simulated dog amylase and AMY copy number has been obtained by lab groups.

Beyond basic life science laboratory skills, this experiment tackles mathematical skills, such as concentration of unknown samples by standard curve through ELISA, statistical testing, and introduces important core concepts in genetics and evolution. In addition, the activity that can create a personal connection and instill a sense of purpose, especially so among dog lovers. To content cat lovers, the design of the mock-up study is flexible and could be modified to include other furry friends.

Keywords: Student retention, lab skills, evolution, genetics, pets.