Maximizing meiotic crossovers

Mardi 20 mai, en salle Lynn Margulis & sur zoom.

Si vous souhaitez rencontrer Raphaël durant son séjour, vous pouvez prendre contact avec lui ou Jean-Marc : mercier@mpipz.mpg.de , Jean-Marc.Routaboul@inrae.fr

Abstract

Meiotic crossovers shuffle parental genetic information, providing novel combinations of alleles on which natural or artificial selection can act. However, meiotic crossovers are relatively rare, typically one to three per chromosome. Intriguingly, crossover numbers differ between males and females in many species. Perhaps even more intriguing, when multiple crossovers occur on a single chromosome, they tend to be distant from each other, a phenomenon called interference, whose mechanisms have been a matter of debate for over a century. 

Using the model plant Arabidopsis thaliana, we revealed multiple mechanisms that limit meiotic crossovers. Mutation of the corresponding genes led to a spectacular-more than 10-fold increase in genome-wide recombination, without a dramatic effect on chromosome segregation and fertility. This shows that crossovers are naturally constrained well below their possible maximum, open possibilities to manipulate crossover rate for plant breeding, and raises the question of the evolutionary forces that limit meiotic crossover. 

Finally, our data and previous results support a unifying emerging model for crossover control, in which the coarsening dynamic of the HEI10 pro-crossover protein along meiotic chromosomes designates crossover position, accounting for crossover numbers, heterochiasmy, and crossover interference.

Zoom

https://inrae-fr.zoom.us/j/95742980367?pwd=HxNZCpUJgrzBobJXMFd4u7WS7wt8JS.1
ID de réunion : 957 4298 0367
Code secret : Mercier25!