Know more

About cookies

What is a "cookie"?

A "cookie" is a piece of information, usually small and identified by a name, which may be sent to your browser by a website you are visiting. Your web browser will store it for a period of time, and send it back to the web server each time you log on again.

Different types of cookies are placed on the sites:

  • Cookies strictly necessary for the proper functioning of the site
  • Cookies deposited by third party sites to improve the interactivity of the site, to collect statistics

Learn more about cookies and how they work

The different types of cookies used on this site

Cookies strictly necessary for the site to function

These cookies allow the main services of the site to function optimally. You can technically block them using your browser settings but your experience on the site may be degraded.

Furthermore, you have the possibility of opposing the use of audience measurement tracers strictly necessary for the functioning and current administration of the website in the cookie management window accessible via the link located in the footer of the site.

Technical cookies

Name of the cookie


Shelf life

CAS and PHP session cookies

Login credentials, session security



Saving your cookie consent choices

12 months

Audience measurement cookies (AT Internet)

Name of the cookie


Shelf life


Trace the visitor's route in order to establish visit statistics.

13 months


Store the anonymous ID of the visitor who starts the first time he visits the site

13 months


Identify the numbers (unique identifiers of a site) seen by the visitor and store the visitor's identifiers.

13 months

About the AT Internet audience measurement tool :

AT Internet's audience measurement tool Analytics is deployed on this site in order to obtain information on visitors' navigation and to improve its use.

The French data protection authority (CNIL) has granted an exemption to AT Internet's Web Analytics cookie. This tool is thus exempt from the collection of the Internet user's consent with regard to the deposit of analytics cookies. However, you can refuse the deposit of these cookies via the cookie management panel.

Good to know:

  • The data collected are not cross-checked with other processing operations
  • The deposited cookie is only used to produce anonymous statistics
  • The cookie does not allow the user's navigation on other sites to be tracked.

Third party cookies to improve the interactivity of the site

This site relies on certain services provided by third parties which allow :

  • to offer interactive content;
  • improve usability and facilitate the sharing of content on social networks;
  • view videos and animated presentations directly on our website;
  • protect form entries from robots;
  • monitor the performance of the site.

These third parties will collect and use your browsing data for their own purposes.

How to accept or reject cookies

When you start browsing an eZpublish site, the appearance of the "cookies" banner allows you to accept or refuse all the cookies we use. This banner will be displayed as long as you have not made a choice, even if you are browsing on another page of the site.

You can change your choices at any time by clicking on the "Cookie Management" link.

You can manage these cookies in your browser. Here are the procedures to follow: Firefox; Chrome; Explorer; Safari; Opera

For more information about the cookies we use, you can contact INRAE's Data Protection Officer by email at or by post at :


24, chemin de Borde Rouge -Auzeville - CS52627 31326 Castanet Tolosan cedex - France

Last update: May 2021

Menu Logo Principal


Zone de texte éditable et éditée et rééditée

PhyloSex - Evolution of Sex Determining genes in Fishes

National program coordinated by Yann Guiguen

Sexual reproduction is one of the most highly conserved processes in evolution and implicates many fields of biology but also animal and plant breeding and human health and society. The genetic and cell biological mechanisms making the decision whether the undifferentiated gonad of the embryo develops either towards male or female are manifold and quite different. Sex determining (SD) mechanism range from environmental to simple or complex genetic mechanisms and have evolved obviously repeatedly and independently. In species with genetic monofactorial sex determination, master SD genes lying on sex chromosomes drive the gonadal differentiation process by switching on a developmental program that ultimately leads to testicular or ovarian differentiation. So far very few sex determining genes have been identified in fish and in animals in general. Fish are uniquely suited to study the evolution of sex determination and SD genes. Comprising about half of the about 60 000 species of vertebrates, fish show also the greatest variety of sex determination mechanism including species with either environmental or genetic sex-determination. Even those few known SD genes are apparently not conserved over a larger number of related orders, families, genera or even species. This frequent evolutionary turnover of SD genes may be explained by the large diversity of these master sex regulators due to the high turnover of fish sex chromosomes. This project has then two major objectives: (1) to screen for potential sex determining genes in many fish species; (2) to demonstrate the role of identified genes as master sex determinants in a few selected species. To address these questions, we have developed a strategy (Rad-Sex) that makes use of next generation sequencing technology to identify genetic markers that define sex specific segments of the male or female genome. The obtained markers will be used to isolate candidates for SD genes from these regions. This approach will be carried out by screening in a first round 30 species representing major branches of the fish tree of life. Rad-Sex markers will identify sex chromosomal regions in the majority of species. From these we will then take the most promising 10 species to find candidate SD genes by screening large insert libraries with the Rad-Sex markers. Isolated clones will be sequenced and analyzed for coding sequences. Candidate genes will be evaluated by transcript profiling and finally a selection of three genes will be taken to functional characterization. The finding of new master SD genes will be of major importance taking into account the very low number of species, in which such genes have been characterized in vertebrates. From a comparative point of view, this project will also have a great impact on what is already known about the evolution of genetic sex determination in vertebrates in general and more specifically in fishes, in which the questions about the evolutionary significance of the high diversity of master sex determining genes and the genomic mechanisms allowing these rapid turnovers are largely unanswered. This project will also have important practical outcomes for molecular sexing that will be important for a better control of sex determination in aquaculture and for ecology and ecotoxicology research in some of the species investigated in this project that are economically or environmentally very important species.


  • Yann Guiguen, Inra LPGP, Rennes, France - French coordinator
  • Manfred Schart, University of Wurzburg, Allemagne - German coordinator
  • John Postlethwait, University Oregon, USA
  • Laurent Journot,CNRS MGX, Montpellier, France