Assessing the Nature and Magnitude of Gametic Isolation between Two Recently Diverged Plant Species

Author: Jamie Axelrod

Field of Study: Biological Sciences; Environmental Science

Faculty Mentors: James Sobel

Easel: 21

Timeslot: Morning

Abstract: Speciation is the process by which populations evolve to become distinct, reproductively isolated species. Reproductive barriers that contribute to isolation continue to accumulate after speciation is complete, making it difficult to determine which barriers contribute most to reproductive isolation. A relatively understudied form of isolation is postmating prezygotic (PMPZ) isolation. PMPZ isolation emerges from interaction between gametes and/or reproductive tissues, affecting the success of fertilization and it is theorized to be an early contributor to population divergence. Studying PMPZ isolation will provide insight into the order in which reproductive barriers evolve, building on previous studies of premating barriers. The study system for this project consists of Mimulus clevelandii and Mimulus aurantiacus, two distinct, recently diverged species. Although they are distinct species, they remain interfertile. As these plants are at an earlier stage of divergence, studying them will provide insight into the nature and magnitude of PMPZ in the Mimulus sect. Diplacus.