Sergey Kryazhimskiy's Avatar

Sergey Kryazhimskiy

@skryazhi.bsky.social

Work in progress | Evolution | Ecology | Systems Biology | Experiments | Theory | Running a lab @ucsdbiosciences | http://sklab.science | https://thoughtsforbreakfast.wordpress.com/

1,560 Followers  |  465 Following  |  261 Posts  |  Joined: 22.08.2023
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Posts by Sergey Kryazhimskiy (@skryazhi.bsky.social)

Very sad news. David Botstein made enormous contributions to molecular biology & genetics. I first met him in a grad school interview. I learned something from him each of the few times I saw him since. Indelible personality. Here he is giving a keynote at the 2015 UCSD Genetics Retreat.

28.02.2026 20:35 β€” πŸ‘ 19    πŸ” 7    πŸ’¬ 3    πŸ“Œ 1

I was sad to learn that my postdoctoral mentor, David Botstein, died yesterday. I started with David as a postdoc in 1998, and he had a profound effect on both my life and scientific career. He was a giant in the field of genetics, making seminal contributions in both yeast and human genetics. 1/

28.02.2026 20:25 β€” πŸ‘ 97    πŸ” 31    πŸ’¬ 5    πŸ“Œ 2

Would love to hear about recent AI experiences of other researchers? @wcratcliff.bsky.social, @baym.lol?

26.02.2026 17:32 β€” πŸ‘ 1    πŸ” 0    πŸ’¬ 2    πŸ“Œ 0

It often goes down rabbit holes and gets confused, but usually manages to pull itself out and eventually focuses on the most reasonable trains of thought. Overall, while it did not offer any new brilliant ideas, the conversation gave me at least one small lead that could be useful. Very cool!

26.02.2026 17:32 β€” πŸ‘ 4    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0

I have to say, I am quite impressed with Claude-Opus-4.6. I had very interesting conversation with it trying to explain a puzzling phenomenon that we observed in our experiments. The internal monologue is fascinating and reveals solid reasoning characteristic of a very good 1st year PhD student.

26.02.2026 17:32 β€” πŸ‘ 9    πŸ” 1    πŸ’¬ 2    πŸ“Œ 0
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Federal funding for US biomedical research is moribund.

Since October 1 2025, NIH is -80% in new grants and -70% in values (total dollars).

Labs are closing down and researchers are leaving science.

To what end?

26.02.2026 15:48 β€” πŸ‘ 69    πŸ” 57    πŸ’¬ 5    πŸ“Œ 12
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Jeffrey Epstein’s tissue samples ignited a furor in the Harvard lab of George Church Exclusive: Harvard geneticist George Church knew more about Jeffrey Epstein's activities than he has previously said, before accepting new donations from the sex offender.

OK I don't have access to the whole article but the overall point / summary is very very troubling www.statnews.com/2026/02/24/e... #epstein

24.02.2026 15:13 β€” πŸ‘ 13    πŸ” 6    πŸ’¬ 2    πŸ“Œ 2

It's just something else that is getting educated πŸ₯²

23.02.2026 18:44 β€” πŸ‘ 1    πŸ” 0    πŸ’¬ 0    πŸ“Œ 0

How to avoid getting an education while paying for one:

23.02.2026 16:36 β€” πŸ‘ 159    πŸ” 34    πŸ’¬ 14    πŸ“Œ 1

It is incredible how out of touch with reality these people are

22.02.2026 02:18 β€” πŸ‘ 1    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0
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#Genomics methodologies can often introduce bias, resulting in inaccurate predictions.

In #GENETICS, Michael Overton and @skryazhi.bsky.social present an improved genotyping pipeline for analyzing mutation accumulation in #yeast with a more reliable statistical estimations. buff.ly/1rcGasy

21.02.2026 17:01 β€” πŸ‘ 5    πŸ” 3    πŸ’¬ 0    πŸ“Œ 0

Country's budget is the clearest quantification of society's values.

21.02.2026 18:36 β€” πŸ‘ 0    πŸ” 0    πŸ’¬ 0    πŸ“Œ 0

Can we simulate realistic evolutionary trajectories and β€œreplay the tape of life”? In this work, we propose a flexible, generalizable deep learning framework for modeling how the entire protein sequence evolves over time while capturing complex interactions across sites. 1/n
doi.org/10.64898/202...

21.02.2026 17:13 β€” πŸ‘ 82    πŸ” 35    πŸ’¬ 3    πŸ“Œ 1

Thanks! I'll reach out by email and we'll coordinate.

21.02.2026 18:02 β€” πŸ‘ 0    πŸ” 0    πŸ’¬ 0    πŸ“Œ 0

It actually looks like complex mutations that we detect carry *more* non-synonymous changes than simple mutations. Hmm...

21.02.2026 18:00 β€” πŸ‘ 1    πŸ” 0    πŸ’¬ 0    πŸ“Œ 0

We see no evidence of that (correlation btw allele frequencies does not decay with genomic distance).

21.02.2026 17:55 β€” πŸ‘ 2    πŸ” 0    πŸ’¬ 0    πŸ“Œ 0

I know! Would love to chat and get your input. We are still trying to find any technical explanations, but we already ruled out most of the things we could think of. The graph above is from Chlamy. Yeast in the same flasks evolves "normally" and dN/dS increases with multiplicity, as expected.

21.02.2026 03:19 β€” πŸ‘ 1    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0

My current hypothesis is that there are more complex mutations among high multiplicity genes, meaning that complex mutations are drivers. But dN/dS estimates become essentially meaningless for such mutations.

20.02.2026 21:21 β€” πŸ‘ 1    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0
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Thanks! We are seeing such complex mutations occurring at very high rates in one of our evolution experiments. And they appear to drive down dN/dS. On the plot below, the x-axis show the multiplicity of a gene (how many times it was hit by mutations in independent lines).

20.02.2026 20:22 β€” πŸ‘ 5    πŸ” 0    πŸ’¬ 2    πŸ“Œ 0
PNAS Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans...

1/5) Re-reading this excellent paper on using mutation-selection balance models to quantify positive selection. The discussed lack of congruence between MK approaches and classic dN/dS test is entirely unsurprising, see thread below.
www.pnas.org/doi/10.1073/...

20.02.2026 15:01 β€” πŸ‘ 13    πŸ” 3    πŸ’¬ 1    πŸ“Œ 1

Presumably, complex multi-nucleotide mutations/substitutions could also lead to false negatives. What's a good reference that discusses such substitutions?

20.02.2026 17:34 β€” πŸ‘ 1    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0

Thanks!

20.02.2026 05:04 β€” πŸ‘ 0    πŸ” 0    πŸ’¬ 0    πŸ“Œ 0

For example, they asked to add a separate reference list to my supplementary data file. Anyone experienced this? I think it's would create unnecessary confusion.

19.02.2026 17:49 β€” πŸ‘ 0    πŸ” 0    πŸ’¬ 0    πŸ“Œ 0

(1) So far, I received 3 sequential requests to update the ms and the supp files. Why can't they just send one complete list? How many more rounds should I expect?

(2) And I have not encountered weirder and stricter requirements for formatting supp files in any other journal!

19.02.2026 17:49 β€” πŸ‘ 0    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0

I have never had a more painful, awkward and inefficient post-acceptance/production experience than in PLoS Computational Biology. [Apparently not on Blue Sky, so tagging @plos.org and EiC @fmacg.bsky.social.]

Is it just me or do others have issues there too?

19.02.2026 17:49 β€” πŸ‘ 0    πŸ” 0    πŸ’¬ 2    πŸ“Œ 0

19 people.

15.02.2026 15:14 β€” πŸ‘ 160    πŸ” 51    πŸ’¬ 8    πŸ“Œ 1
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CU signs $2M OpenAI deal for ChatGPT access Students and faculty will gain access to ChatGPT Edu starting in March under a three-year deal.

My employer, Univ. Colorado will pay OpenAI $2M/year under the banner of β€œequity”. That’s 54 full scholarships / year. Plus, our IT will be able to read our chatGPT logs, and our chats can be requested under public records law. No thanks. Surveillance is not equity

www.axios.com/local/boulde...

13.02.2026 23:36 β€” πŸ‘ 657    πŸ” 286    πŸ’¬ 30    πŸ“Œ 47

Job opportunities...

Newly launched Quantitative Biology Initiative in the Department of Biology at the University of Maryland, College Park seeks applications for three collaborative postdoctoral fellowships. Best consideration date 3/14.

Full Details:
umd.wd1.myworkdayjobs.com/en-US/UMCP/j...

11.02.2026 20:13 β€” πŸ‘ 20    πŸ” 30    πŸ’¬ 3    πŸ“Œ 0
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Davis Summer Population Genomics Program Want to learn population genetics? Please fill out this form to indicate your potential interest in a 2-week intensive online summer population genetics course taught by Jeffrey Ross-Ibarra and Graham...

Fun news! @gcbias.bsky.social and I are teaching a 2-week online population genetics workshop this summer to raise money for the Center for Population Biology at UC Davis. We're trying to gauge interest -- please fill this out if you might be interested! And please share broadly!

09.02.2026 18:24 β€” πŸ‘ 137    πŸ” 169    πŸ’¬ 7    πŸ“Œ 5
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Black Square - Wikipedia

Hard to believe it, but you surpassed Malevich
en.wikipedia.org/wiki/Black_S...

07.02.2026 06:38 β€” πŸ‘ 2    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0