Cellular sex and physiology

Main interests

  • Sex differences in development, metabolism and behaviour
  • Molecular pathways mediating sex chromosome effects
  • Evolution of sexual dimorphism
  • Anatomy and physiology of the reproductive systems

Scientific Questions

An individual can be characterized by the presence of particular sex organs: testes or ovaries. Formation of these reproductive organs is controlled by specific genetic elements: the sex chromosomes. But sex differences encompass much more than sex organs. Evidence suggests that males and females differ in their normal physiology and susceptibility to a broad range of diseases. These disparities underscore the importance of identifying all the places in the body impacted by sex chromosomes. But besides sex organs we have been operating with a unisex vision of cell and organ functions and implications of sex chromosome presence have been overlooked.

Our long-term objective is to understand where, and how the intrinsic presence of sex chromosomes, cellular sex, drives sex differences in development, physiology, and pathologies. We are currently studying these fundamental questions using Drosophila as an in vivo model.

Our Strategy

Our group aims to understand how sex chromosome constitution (XX versus XY) impacts physiology across the body. In particular, we want to establish which organs have a sex chromosome set that actively regulates their physiology and how sex chromosome effects are mediated. These questions have been poorly investigated. This is due in part to the difficulty of studying sex chromosome effects in complex higher organisms. In the team, we are using fruit flies to tackle these research questions. Flies have simpler but functionally analogous sex chromosomes and offer the remarkable possibility to generate mosaic animal in which sex chromosomes are genetically manipulated in defined organs. Given the functional similarities between flies and humans, the sex chromosome effects we will uncover in the fly are likely to be relevant to higher organisms and operate in many diseases presenting sexually dimorphic characters.

Our current work aims at identifying new genes/pathways and concepts driving sex chromosome effects using multi-scale approaches combining biochemistry, genetics and cell biology. More specifically, we design genetic and molecular screens to i) identify new target genes downstream of the fly master-switch sex-determining gene, transformer, ii) establish Drosophila as a new paradigm to study somatic loss of the Y chromosome, iii) identify new genes involved in the control of sexual dimorphic trait evolution.

Research Aims

Although our work has demonstrated the impact of the sex determinant transformer in adult intestinal stem cells, the general significance of cellular sex remains poorly understood. In addition, little is known about the molecular mechanisms through which transformer exerts its influence in this new cellular context. Our objectives here are the following: i) to characterise organism-wide where and when cellular sex is required, and ii) to decipher NEW SEX PATHWAYS downstream of transformer.

It is widely unknown HOW SEXUAL DIMORPHIC TRAITS CAN EVOLVE so rapidly. In fact, reproductive structures, behaviours and secondary sexual characteristics are some of the most variable and changeable features among insects. These changes may require the rapid evolution rate of the underlying master-switch sex-determining gene. We are currently testing this hypothesis using the sex determinant transformer and closely related Drosophila species as a model

SOMATIC LOSS OF THE Y CHROMOSOME (LOY) is the most common acquired human mutation; its frequency increases with age and is associated with decreased survival time from all causes. Yet the full range of phenotypic consequences of LOY, the genes and mechanisms involved remain elusive. We are developing a technology to achieve for the first time conditional and cell-type specific deletion of entire sex chromosomes. This strategy will be use to model LOY during normal and pathological conditions


DELANOUE Renald - +33


FRANçOIS Charlotte - +33

Engineers & Technicians

PIHL Thomas - +33 489150763


Recent publications

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2018 - Young team leader starting grant, ATIP-AVENIR (CNRS)

iBV - Institut de Biologie Valrose

"Centre de Biochimie"

Université Nice Sophia Antipolis
Faculté des Sciences
Parc Valrose
06108 Nice cedex 2