helsenjana.bsky.social
Evolutionary cell biology, chromosomes, yeasts, and occasional SciArt🧬🧪🎨. Postdoctoral fellow at the labs of Gautam Dey (EMBL) and Gavin Sherlock (Stanford University).
39 posts
1,405 followers
831 following
Regular Contributor
Active Commenter
comment in response to
post
Super nice to see this out! Congrats Hashim!
comment in response to
post
Thank you, that's very nice to hear! 😁
comment in response to
post
Thank you Max! 😁
comment in response to
post
This rewarding project came to fruition with the help of my amazing colleagues @gsherloc.bsky.social, @gautamdey.bsky.social, and @kausthubh.bsky.social, and with the support of @embl.org, Stanford University, and the Life Science Alliance. (8/8)
comment in response to
post
Our study challenges the traditional view of centromere drive as the sole driver of centromere evolution. We propose a multi-faceted model involving drift and selection during both mitosis and meiosis, shaped by constraints imposed by the kinetochore interface. (7/8)
comment in response to
post
Centromere transitions aren't random!
Our findings suggest that the kinetochore interface dictates which centromere changes are tolerated. Coevolution between the kinetochore and centromere sequences likely drives these constrained transitions. (6/8)
comment in response to
post
Centromere variants can also spread through populations via sexual reproduction. In budding yeasts, microhomology-mediated mutations seem to be the key driver in the emergence of these novel centromere variants. (5/8)
comment in response to
post
Centromere transitions turn out to be a gradual, step-by-step process. Through simulations and in vivo centromere function experiments, we show that selection plays a crucial role in driving these changes! (4/8)
comment in response to
post
We developed a new tool, PCAn 🔍, to systematically map point centromeres across budding yeasts, revealing remarkable centromere variation! (3/8)
comment in response to
post
Unlike genes, species with monocentric chromosomes possess multiple centromeres, one on each chromosome. This makes centromere evolution conceptually quite different from gene evolution.
Our work aimed to shed light on the fundamental evolutionary principles underlying centromere transitions. (2/8)
comment in response to
post
Subconscious motivation, I promise, but I was indeed somewhat intrigued by those covers as a child 😂
comment in response to
post
Amazing, thank you 😁
comment in response to
post
I'm one of those! Can I be added?
comment in response to
post
I'd love to be added!
comment in response to
post
This is great! Can I be added too?
comment in response to
post
Thank you so much, that's so nice to hear! Always happy to answer any questions that might come up 😊
comment in response to
post
Just the list I was looking for, thank you! I'd love to be included too if there's still space.
comment in response to
post
Thanks so much 😁
comment in response to
post
Thanks for putting this together! I'd also love to be included 🙋
comment in response to
post
Curious what changes we made since our preprint from October ‘23? Check out the peer reviewer reports. Also, you can check out this complementary study from 2 weeks ago in @CurrentBiology examining the spindle defects of 2-chromosome strains doi.org/10.1016/j.cub.2024.06.058 9/9
comment in response to
post
This rewarding project came to fruition with the help of my amazing colleagues @gsherloc.bsky.social , @gautamdey.bsky.social, Hashim Reza and Ricardo Carvalho, and with the support of EMBL, Stanford University, and the Life Science Alliance. 8/9
comment in response to
post
To summarise: the budding yeast spindle robustly supports karyotypes with at least 5 chromosomes, showcasing how core cellular features can set limitations for evolution. 7/9
comment in response to
post
Why do cells need at least 5 centromeres? Our study reveals that 4 kinetochore microtubules cannot generate sufficient inward force to counteract the outward forces in the metaphase spindle, causing kinetochores to decluster and triggering the spindle assembly checkpoint. 6/9
comment in response to
post
How does diploidization get rid of a mitotic delay? Diploidization effectively doubles the number of chromosomes above the critical limit. Turns out having 5 centromeres is sufficient to completely overcome the delay. 5/9
comment in response to
post
What exactly is the cause of this delay? By evolving cells with low chromosome counts in the lab, we show that cells can completely get rid of this delay through one quick fix ⇨
diploidization. 4/9
comment in response to
post
Using a set of budding yeast strains in which the native chromosomes have been successively fused, we show that cells can tolerate large changes in karyotype. But, only up until a critical point: cells with fewer than 5 chromosomes experience a mitotic delay. 3/9
comment in response to
post
Chromosome numbers can vary widely in nature, even between closely related species. Despite this, the mitotic machinery must accurately segregate each chromosome every cell cycle. We sought to understand the physical constraints dictating chromosome number evolution. 2/9
comment in response to
post
Thanks Omaya 😊
comment in response to
post
To summarise: the budding yeast spindle robustly supports karyotypes with at least five chromosomes, showcasing how the mechanics of a core cellular process can constrain evolutionary processes. 8/8
comment in response to
post
This in turn causes kinetochore declustering, triggering of the spindle assembly checkpoint, and results in a delay in metaphase. 7/8
comment in response to
post
What goes wrong in cells with fewer than five centromeres? We show that in these cells, the number of kinetochore-microtubule attachments is insufficient to counter outward forces in the metaphase spindle. 6/8
comment in response to
post
How does diploidization repair the defect? Diploidization effectively doubles the number of chromosomes above the critical limit, and we show that having five centromeres is sufficient to overcome both the growth and mitotic defect. 5/8
comment in response to
post
Can cells repair this defect? We evolved cells with low chromosome counts in the lab, and show that cells can indeed overcome the growth defect, and they do so by diploidization. 4/8
comment in response to
post
Using a set of budding yeast strains in which the native chromosomes have been successively fused, we show that cells tolerate large changes in karyotype very well, but only up until a critical point. Cells with fewer than five chromosomes display both growth and mitotic defects. 3/8
comment in response to
post
Chromosome numbers can vary widely in nature, even between closely related species. Regardless, the mitotic machinery must accurately segregate each chromosome every cell cycle. Here, we set out to explore the physical constraints dictating chromosome number evolution. 2/8