Timing matters: how do physiology and genetics facilitate reproduction early on in life?

Background and approach

Reproduction is directly linked to evolutionary success, and timing is a key characteristic of the reproductive process. The ability to have a high level of reproduction early on in life is intricately correlated with changes in other phenotypes, including lifespan, cognition, metabolism, and immunity. Yet, we know very little about the mechanisms responsible for variation in early reproduction. The aim of this set of projects is to understand the genetic networks and physiological processes involved, by studying natural variation in early reproduction, defined as time needed to lay the first 50 eggs, in the powerful genetic model Drosophila melanogaster (fruit flies). Your project would focus on one of the subtopics below, or combinations thereof:

(A) “From guts to (reproductive) glory”: reproduction is hugely energetically costly and has profound effects on animal physiology: after mating, females will undergo an extensive remodeling of their metabolism and the morphology of various organs, such as the gut and the ovaries to ensure the availability of sufficient nutrients to support reproduction. In this project, you will screen a panel of wildtype Drosophila lines that differ in early reproduction. You will assess (1) changes in the morphology of the gut and the ovaries before and after mating, (2) the metabolic capacity of these lines, by measuring lipid and carbohydrate content, and/or (3) resource allocation towards different organs by stable isotope labeling. This will help us understand which aspects of the reproductive process are involved in the adaptation of early reproduction. (*precise assays depend on your interests and regulations related to COVID-19).

(B) At the genetic level, reproduction is associated with profound changes in gene expression networks after mating, including distinct temporal patterns of gene expression as well as tissue-specific responses, for example in the brain or the reproductive organs. It is not clear, however, which of these factors may control variation in early reproduction, specifically. In this project you will do a comparative (meta-)analysis in which you try to link these various gene expression (transcriptome) datasets, to genomic datasets from experimentally evolved populations that adapted timing of reproduction. The aim is to identify promising candidate for the regulation of early reproduction. Some of these candidates may be validated using RT-qPCR or RNAi in your project.

Supervision and information

Dr. Katja Hoedjes (Room H128, W&N building, Vrije Universiteit)
E-mail: k.m.hoedjes@vu.nl