Know more

Our use of cookies

Cookies are a set of data stored on a user’s device when the user browses a web site. The data is in a file containing an ID number, the name of the server which deposited it and, in some cases, an expiry date. We use cookies to record information about your visit, language of preference, and other parameters on the site in order to optimise your next visit and make the site even more useful to you.

To improve your experience, we use cookies to store certain browsing information and provide secure navigation, and to collect statistics with a view to improve the site’s features. For a complete list of the cookies we use, download “Ghostery”, a free plug-in for browsers which can detect, and, in some cases, block cookies.

Ghostery is available here for free: https://www.ghostery.com/fr/products/

You can also visit the CNIL web site for instructions on how to configure your browser to manage cookie storage on your device.

In the case of third-party advertising cookies, you can also visit the following site: http://www.youronlinechoices.com/fr/controler-ses-cookies/, offered by digital advertising professionals within the European Digital Advertising Alliance (EDAA). From the site, you can deny or accept the cookies used by advertising professionals who are members.

It is also possible to block certain third-party cookies directly via publishers:

Cookie type

Means of blocking

Analytical and performance cookies

Realytics
Google Analytics
Spoteffects
Optimizely

Targeted advertising cookies

DoubleClick
Mediarithmics

The following types of cookies may be used on our websites:

Mandatory cookies

Functional cookies

Social media and advertising cookies

These cookies are needed to ensure the proper functioning of the site and cannot be disabled. They help ensure a secure connection and the basic availability of our website.

These cookies allow us to analyse site use in order to measure and optimise performance. They allow us to store your sign-in information and display the different components of our website in a more coherent way.

These cookies are used by advertising agencies such as Google and by social media sites such as LinkedIn and Facebook. Among other things, they allow pages to be shared on social media, the posting of comments, and the publication (on our site or elsewhere) of ads that reflect your centres of interest.

Our EZPublish content management system (CMS) uses CAS and PHP session cookies and the New Relic cookie for monitoring purposes (IP, response times).

These cookies are deleted at the end of the browsing session (when you log off or close your browser window)

Our EZPublish content management system (CMS) uses the XiTi cookie to measure traffic. Our service provider is AT Internet. This company stores data (IPs, date and time of access, length of the visit and pages viewed) for six months.

Our EZPublish content management system (CMS) does not use this type of cookie.

For more information about the cookies we use, contact INRA’s Data Protection Officer by email at cil-dpo@inra.fr or by post at:

INRA
24, chemin de Borde Rouge –Auzeville – CS52627
31326 Castanet Tolosan CEDEX - France

Dernière mise à jour : Mai 2018

Menu INRA Clermont Auvergne University

UMR GDEC

Joint Research Unit 1095 Genetics, Diversity and Ecophysiology of Cereals

Task 2 : Organization

Principle : Polyploidization is followed by a diploidization process at the genome and gene levels.

Duplication of chromosomes, or polyploidy at large, are followed by a return to the diploid state through a process called diploidization that we investigated at two levels of resolution: gene and chromosome. At the chromosome level, we observed that successive rounds of polyploidy were followed by ancestral chromosome fusions. The genomes of modern plants and animals appear as a mosaic of fused ancestral chromosomes. Our work demonstrated that the appearance of new plant species was related to the fusion/fission of chromosomes and each modern species could then be associated with a specific pattern of ancestral chromosome fusions/fissions. However, while the chromosomal fusions in cereals are centromeric (CCF for 'Centromeric Chromosome Fusion'), chromosomal fusions appear telomeric (TCF for 'telomeric Chromosome Fusion') in animals. These regions of ancestral chromosomes fusion regions become over time the preferential location of intense rearrangements via the insertion of repeats and tandem gene duplications.

At the gene level, the diploidization process leads to a loss and/or differential transposition of duplicated genes from paralogous blocks. We have established that this deletion / transposition of duplicated genes is not random and preferentially observed on one of the subgenomes (following genome duplication). This dominance and / or sensitivity of the subgenomes (or intra-genomic) following a duplication event is more pronounced in plants which have undergone recurrent and recent polyploidies unlike animals.

Duplication_english

Plant genome diploidization processes (Salse 2012). [Left]- Diploidization at the chromosome level. The model begins with WGD, followed by ancestral chromosome fusions, producing a diploidized paleopolyploid karyotype. A derived duplicated region with different gene contents (colored bars) is illustrated in the centre. [Right]- Diploidization at the gene level. The figure illustrates the reduction in duplicated gene redundancy after WGD through non-functionalization (gene deletion), sub-functionalization (new expression pattern via regulatory sequence shuffling shown as a pink bar), neo-functionalization (new function through functional domain shuffling shown as a pink bar), concerted evolution (expression and functional redundancy retained) mechanisms. The consequences for duplicated gene structures and expression patterns are schematically illustrated in colored boxes at the right.