A single theory for the evolution of sex chromosomes and the two rules of speciation Sex chromosomes are involved in three major empirical patterns: (i) Y (or W) chromosomes are often nonrecombining and degenerate; (ii) heterogametic offspring (XY or ZW) from interspecific crosses are...

Interested to know more about a new theory relating the #evolution of #sexchromosomes to the rules of #speciation? Check out this paper that we published with Denis Roze in the last issue of #Science. PDF here: www.science.org/stoken/autho...

RPA directly stimulates Mer3/HFM1 helicase processivity to ensure normal crossover formation in meiosis Meiotic crossover formation is critical for generating viable gametes and enhancing genetic diversity. The helicase Mer3 (HFM1 in humans) is a highly conserved factor essential for promoting crossover...

www.biorxiv.org/content/10.1...

Potatoes Evolved From … Tomatoes? Dipping fries into ketchup just got a little more mind-bending.

Scientists have spent decades puzzling over potatoes’ origin story. The answer was juicier than anyone expected, @katherinejwu.com reports.

Open Call for Expressions of Interest in Max Planck Directorships: Expressions of interest can be submitted until 31 October 2025.

Director at Max Planck - a unique position! The Open Call for Expressions of Interest in Max Planck Directorships is open now and can be submitted by the 31st of October 2025. ➡️ mpg.de/directors - Please share the Open Call among potential candidates.

When the professor edits the student's draft

It's not procrastination i'm thinking

Cette année, les Journées Scientifiques et Techniques (JST2025) du Réseau des Microscopistes INRAE (RµI) sont à Versailles!!! C'est du 5 au 7 novembre 2025 et les inscriptions sont ouvertes !!! 🔬👑✨ @ijpb-versaillescly.bsky.social

👇👇👇

rmui-2025.journees.inrae.fr

Just submitted two..

Hibiscus plant with two different coloured flowers

For all plant developmental biologists out there - has been orange flowered for 20 years. Will be tracking the pink branch from now on!

#TodayOnMyBike

#TodayOnMyBike

Diagram of two types of reproduction based on their meiosis. A. shows typical meiosis taking place in individuals with two copies of each chromosome (diploids) resulting in both male and female gametes carrying one copy of each chromosome. Fertilization restores the double copy for each chromosome. B. shows Canina meiosis in individuals carrying five copies of each chromosome (pentaploids) where male gametes only carry one copy of each chromosome and female gametes carry four copies of each chromosome. Fertilization restores the five copy for each chromosome.

Check out the Views & News piece that Joiselle Fernandes and I wrote for @nature.com on the recent work from @amarques.bsky.social and colleagues about one of the most bizarre ways to do meiosis rdcu.be/euabu.

Explained for non-experts!

I am super happy to see our dog rose's paper featuring the cover of the July 3rd issue of @nature.com

read more here: tinyurl.com/dog-rose

Bimodal centromeres in pentaploid dogroses shed light on their unique meiosis - Nature Insights into the dogrose genome and centromeres explain their ability to achieve stable sexual reproduction.

Nature research paper: Bimodal centromeres in pentaploid dogroses shed light on their unique meiosis

https://go.nature.com/407PRGm

Bimodal centromeres in pentaploid dogroses shed light on their unique meiosis - Nature Insights into the dogrose genome and centromeres explain their ability to achieve stable sexual reproduction.

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I am very excited to announce our🌹NEW PAPER OUT IN 𝑁𝐴𝑇𝑈𝑅𝐸!🌹
𝐃𝐑𝐈𝐕𝐄 𝐓𝐎 𝐒𝐔𝐑𝐕𝐈𝐕𝐄: Bimodal centromeres in pentaploid dogroses shed light on their unique meiosis
With the Ritz and Kovařík labs we show a potential role for centromeres on 𝘙𝘰𝘴𝘢 𝘤𝘢𝘯𝘪𝘯𝘢 bizarre reproduction!
www.nature.com/articles/s41...

🎉 We’re thrilled to share that our director Miltos Tsiantis has been awarded an ERC Advanced Grant @erc.europa.eu for his project CLONAL, which will explore the development and diversity of root suckers. Congratulations! 🌱👏Learn more: bit.ly/43KuvBe #ERCAdG #plantsci

#TodayOnMyBike

Maximizing meiotic crossover rates reveals the map of Crossover Potential - Nature Communications Meiotic crossovers enhance genetic diversity in sexually reproducing organisms. Here, the authors propose that the higher-order spatial organization of the meiotic chromosomes shapes sexual dimorphism...

More in the paper: www.nature.com/articles/s41...

We propose that COP reflects the density of eligible recombination precursors, which is determined by genomic features and is thus identical across sexes, with sexual dimorphism resulting solely from differential regulation of their maturation into crossovers.

a close up of a woman 's face with a triangle and a mathematical formula . ALT: a close up of a woman 's face with a triangle and a mathematical formula .

Interestingly, COp can be accurately predicted using only sequence and chromatin features.

a lake in the middle of a mountain range ALT: a lake in the middle of a mountain range

While wild-type crossover patterns differ between sexes. But, the distributions of COs along the genome in various mutant combinations converge to a common profile in both females and males, which diverges markedly from the wild-type distribution. We term this new profile Crossover Potential (COp).

In wild-type males, there are more crossovers than in female (heterochiasmy). Intiguingly, in many of the mutants examined here, heterochialsmy is inverted whith more CO in females. This shows that while CO levels are higher in male wild-type, the potential for CO formation is higher in females.

garfield is walking on the sidewalk with the words `` can 't do this reached physical limits '' . ALT: garfield is walking on the sidewalk with the words `` can 't do this reached physical limits '' .

Manipulating additional CO regulators in zyp1 recq4 did not further increase CO frequency but altered the ratio of class I and class II COs. This suggests that an upper limit had been reached and that the two pathways compete for a large but limited number of CO precursors.

two women are sitting next to each other and one is pointing at the camera ALT: two women are sitting next to each other and one is pointing at the camera

Notably, crossovers in zyp1 recq4 showed a 12-fold increase in females and a 4.5-fold increase in males. 35 Crossovers per female gamete compared to 2.8 in wild-type! This the highest increase described so far.

two women are working hard on a conveyor belt . ALT: two women are working hard on a conveyor belt .

In this study, we pushed crossovers by manipulating one, two, three, or four crossover regulators in Arabidopsis. We examined crossovers frequency in thousands of progenies derived from female and male crosses.

Meiotic crossover shuffle genetic information. But their number are relatively low, ~1-3 per chromosome. Intriguingly crossover frequency and distribution among chromosome often differ between male and female.

Maximizing meiotic crossover rates reveals the map of Crossover Potential - Nature Communications Meiotic crossovers enhance genetic diversity in sexually reproducing organisms. Here, the authors propose that the higher-order spatial organization of the meiotic chromosomes shapes sexual dimorphism...

Paper alert! #Meiosis4Ever

Maximizing meiotic crossover rates reveals the map of Crossover Potential

Juli Jing, Qiachao Lian and Stephanie Durand
www.nature.com/articles/s41...

We pushed meiotic crossover as much has we could, and had some surprises

A thread 👇

#TodayOnMyBike

A property map showing four buildings each labeled with a number 1 through 4. The legend reveals that the building labeled "1" is in fact "Building 4", "2" is "Building 3", "3" is "Building 1", and you guessed it "4" is "Building 2"

Prepping my #datavisualization slides tomorrow's class means it is once again time for my favorite annual activity: finding new awful charts to include. What a beauty!

Nobel laureate: I owe America my success. Today, its scientific future is in danger | CNN Dr. Ardem Patapoutian says he watches “with deep sadness as the United States’ remarkable scientific enterprise, which took generations of hard work and national investment to build, faces a concerted...

Published an op-ed for @cnn.com: “Nobel laureate: I owe America my success. Today, its scientific future is in danger.”
A personal reflection on what’s at stake as science funding gets slashed. I’d be grateful if you could amplify both in and beyond the science world.
www.cnn.com/2025/04/09/h...