Late Lunch Talk: Unraveling the functional significance of complex sperm design and behavior
Late Lunch Talk by Kristin Hook
Sperm aggregation in Peromyscus
Despite sharing a common goal to reach and fertilize an egg, sperm cells have undergone extensive evolutionary modification and are one of the most diverse cell types in existence. Rodent sperm are particularly diverse – they vary within and across species, typically feature a mysterious hook on their head, and a rare few exhibit unique collective behaviors in which they form motile aggregations of cells that are hypothesized to be useful in outcompeting rival sperm. While this structural and behavioral variation is well established, its functional significance remains elusive. Here I present my most recent work investigating the complex sperm shapes and behaviors observed across species of Peromyscus mice, in which the sperm of some species form coordinated groups of multiple cells that swim together. My research project addresses fundamental questions regarding the relationship between sperm structure and function, the biological advantage of complex sperm design, and specific hypotheses about the role of female promiscuity in the evolution of sperm aggregation behavior. Basic research on sperm traits is important because it can be useful for optimizing assisted reproductive techniques and conservation programs as well as shed light on which traits influence fertilization success, which is critical for understanding sexual selection – a major driving force that generates biodiversity.