Title: Macroevolution of Gene Expression in Passerine Birds
Abstract: A key objective of evolutionary biology is to decipher the molecular mechanisms driving phenotypic diversity. While genomes provide the informational foundation of life, gene expression plays a critical role in influencing the evolutionary trajectory of diversity. Understanding how gene expression evolves on a macroevolutionary level and contributes to phenotypic variation is essential to understanding these evolutionary processes. Advancements in technologies such as RNA-Seq and evolving computational tools have enabled comparative transcriptomics to play an increasingly important role in this field. However, the use of comparative transcriptomics to study these questions is still limited. My dissertation investigates the macroevolutionary dynamics of gene expression in passerine birds and assesses the relationships between life history traits and gene expression evolution.
In Chapter 1, I provide a review of the history of transcriptomic technology, the importance of RNA preservation in museum collections, and the current landscape of comparative transcriptomics. I discuss major recent developments and future directions in comparative transcriptomics. In Chapter 2, I empirically investigate the macroevolutionary dynamics of gene expression in the two major clades of passerines: oscines and suboscines. To enable this analysis, I sequenced 327 transcriptomes from six key tissues (heart, pectoralis major, liver, brain, eye, and testis) across 22 passerine species and two outgroup species. Using this dataset, I ask which macroevolutionary models (including Brownian motion and the Ornstein–Uhlenbeck process) best fit the patterns of gene expression observed in these clades and what genes are differentially expressed between oscines and suboscines. I contextualize my findings among previous comparative transcriptomic studies in other taxa, discuss the limitations of small datasets, and highlight the need for more robust models of expression evolution. Finally, in Chapter 3, I examine the relationship between gene expression evolution and avian life history traits, specifically diet and migration. My data reveal a significant relationship between migratory strategy and diet and gene expression across avian organs. The findings from my dissertation enhance our understanding of gene expression evolution in passerine birds and provide valuable insights into how life history traits correlate with gene expression across species.
Committee: Scott Edwards, Dan Hartl (Chair), Matthew Harris (HMS Genetics), Stephanie Pierce
LOCATION:Bio Labs Lecture Hall 1080 STATUS:CONFIRMED DTSTART:20240829T140000Z DTEND:20240829T140000Z END:VEVENT END:VCALENDAR