Dissertations, Theses, and Capstone Projects

Date of Degree

2-2018

Document Type

Dissertation

Degree Name

Ph.D.

Program

Biology

Advisor

Mandë Holford

Advisor

David F. Gruber

Committee Members

John Sparks

Dimitri D. Deheyn

Ana Riesgo Gil

Subject Categories

Evolution | Genomics | Marine Biology

Keywords

Bioluminescence, venom, comparative transcriptomics, convergent evolution, annelida, polychaeta

Abstract

The convergent evolution of phenotypic traits is a widespread phenomenon across the tree of life and is explained as the outcome of different taxa facing similar selective forces or environmental conditions. A longstanding question in evolutionary biology is whether the evolution of convergent phenotypes in unrelated lineages is driven by similar or different molecular processes. The research presented here investigates this question by characterizing the molecular basis of two biochemical innovations, bioluminescence and venom production, that have evolved independently in different lineages of polychaetes worms (Annelida). We use an integrative approach, combining next-generation sequencing, phylogenetics and computational tools to evaluate whether these two convergent traits are the result of similar genetic and molecular mechanisms in different lineages. We have generated a great amount of genomic resources that allowed us to investigate bioluminescence and identify candidate genes responsible for light production in three species of Syllidae (Chapters 2 and 3) and Polynoidae (Chapter 4), as well as a wide diversity of putative toxins in the transcriptomes of three Amphinomidae species (Chapter 5) and four Polynoidae species (Chapter 6). Our results provide a more comprehensive scenario to understand the molecular basis, gene expression patterns and evolution of bioluminescence and venom production in polychaetes, and suggest that convergent traits are generally the result of similar molecular mechanisms in unrelated lineages.

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