Natural variation in genes controlling learning potential

Adapting to a complex environment requires the brain to form an accurate internal representation of the external world. The brain refines its connectivity based on early exposure to the environment. The most robust time for rewiring, or plasticity, occurs just after birth and closes down shortly thereafter. In mice, this critical period, as well as learning ability, is regulated by a brain gene called lynx1. Mice expressing very low levels of lynx1 have enhanced learning potential, but also exhibit neurodegeneration. On the other hand, mice expressing intermediate levels of lynx1 still have enhanced learning potential compared to wild-type mice, but do not exhibit neurodegeneration.

 

For species in which memory and learning influence survival, intermediate levels of lynx1 may be selectively favored. Evolution by natural selection can only occur, however, when heritable variation exists for traits important for fitness. If variation in the lynx1 amino acid sequence has functional consequences, then we might expect natural populations to harbor genetic variation at this locus—especially for species in which learning and memory are important for fitness.

 

Our goal for this study is to assess the amount of variation in the lynx1 amino acid sequence in a natural population of Black-capped chickadees—a species that relies on memory of food storage locations for survival during the winter. We will capture wild chickadees, collect blood samples, extract DNA from these samples, design primers, amplify and sequence the lynx1 gene, and assess the level of variability in the lynx1 sequence among individuals. Results from this project will provide novel information about lynx1 in natural populations, and will form a foundation for future work linking this variation to learning aptitude in a variety of environments.