Ryan Hernandez
rdhernand.bsky.social
Ryan Hernandez
@rdhernand.bsky.social
From busboy/car washer to population geneticist at UCSF, co/Director of the BMI PhD program & UCSF PREP/PROPEL Programs!!!
Reposted by Ryan Hernandez
PEQG! My favorite conference ever*. Single session, fantastic talks, great discussions. Only once every 2 years. And in the best conference location too! Abstract deadline coming up Feb 5!

*Disclosure: I am required to say it's the best conference because it is and I told my mom I wouldn't lie.
Homepage - 2026 Population, Evolutionary, and Quantitative Genetics Conference
Visit our website to learn more.
genetics-gsa.org
January 23, 2026 at 2:37 PM
Reposted by Ryan Hernandez
The meeting will take place at the gorgeous IslandWood Resort on Bainbridge Island, a short ferry ride from downtown Seattle.

Registration is free. We will cover travel and lodging for graduate students, and at least partially subsidize those costs for postdocs and assistant professors.
Outdoor Meeting and Retreat Venue – IslandWood
islandwood.org
January 17, 2026 at 11:51 AM
Reposted by Ryan Hernandez
Excited to share our new preprint from the @arbelharpak.bsky.social Lab!

How do recruitment into genetic studies and study characteristics impact what we infer about the genetic bases of traits, and what are the consequences? (1/21)

www.biorxiv.org/content/10.6...
Representation in genetic studies affects inference about genetic architecture
Knowledge of a trait's "genetic architecture," namely the joint distribution of allele frequencies of causal variants and the direction and magnitude of their effects, is essential to understanding it...
www.biorxiv.org
January 14, 2026 at 7:07 PM
Reposted by Ryan Hernandez
How well does TWAS estimate a gene’s direction of effect on a trait? We think of this as an important stress-test for the accuracy of TWAS.

In a new pre-print, we find that TWAS gets the sign wrong around 20-30% of the time!

doi.org/10.64898/202...

1/n
High false sign rates in transcriptome-wide association studies
Transcriptome-wide association studies (TWAS) are widely used to identify genes involved in complex traits and to infer the direction of gene effects on traits. However, despite their popularity, it r...
doi.org
January 6, 2026 at 2:30 AM
Reposted by Ryan Hernandez
Here's my latest contribution to the @nytimes "Lost Science" series. Brenna Henn's sweeping study of African genetics has been frozen. Gift link: nyti.ms/3Ypmm1A
January 5, 2026 at 5:32 PM
Oh come on… it is January SECOND. Who ALREADY broke our cluster?? #Wyntoff
January 2, 2026 at 7:05 PM
This story is heartbreaking. Brenna Henn is a wonderful scientist, and the work their lab does is truly insightful. Anger and rage…

www.nytimes.com/2026/01/02/s...
January 2, 2026 at 4:30 PM
Reposted by Ryan Hernandez
I'm usually skeptical about AI research tools. But Google's new tool for literature search is fantastic - because it does less, not more. New post:

substack.com/home/post/p-...
Google's New AI Tool Can't Do Much. That's Exactly the Point
Finally, an AI research tool that doesn't hallucinate papers
substack.com
January 1, 2026 at 4:56 PM
Reposted by Ryan Hernandez
Putting on my hat as @asn-amnat.bsky.social ASN President for a minute for a string of announcements, please share widely!!!

1. Student research awards are open for applications, to fund research expenses for 10 graduate students ($2000 each)
nam10.safelinks.protection.outlook.com?url=https%3A...
Student Research Award
<p>The ASN Student Research Awards support research by student members that advances the goals of the society: the conceptual unification of ecology, evolution, and behavior. Each award consists of a ...
nam10.safelinks.protection.outlook.com
November 25, 2025 at 5:55 PM
Reposted by Ryan Hernandez
Grateful to share our paper on gene-specific selective sweeps in human gut microbiomes, now out in Nature! It has been a joy to work with @rwolff.bsky.social, whose insights and hard work made this possible.
www.nature.com/articles/s41...
Gene-specific selective sweeps are pervasive across human gut microbiomes - Nature
Development and application of the integrated linkage disequilibrium score (iLDS) reveals both selective pressures impacting the human gut microbiome and the mechanisms by which gut bacteria adapt to ...
www.nature.com
December 17, 2025 at 6:53 PM
Reposted by Ryan Hernandez
Our latest preprint revisits the classic model of mutation-selection balance.

Do human recessive genes fit Haldane's 100-year old model?

This work is by the wonderful @jonj-udd.bsky.social, and co-mentored by @jeffspence.github.io

www.biorxiv.org/content/10.6...
Allele Frequencies at Recessive Disease Genes are Mainly Determined by Pleiotropic Effects in Heterozygotes
The classic theory of mutation-selection balance predicts the equilibrium frequency of genetic variation under negative selection. The model predicts a simple relationship between the total frequency ...
www.biorxiv.org
December 13, 2025 at 4:45 PM
Reposted by Ryan Hernandez
Normalization of glucose in people with prediabetes, i.e. achieving remission, is linked to halving of major cardiovascular adverse events over ensuing decades
www.thelancet.com/journals/lan...
Prediabetes remission and cardiovascular morbidity and mortality: post-hoc analyses from the Diabetes Prevention Program Outcome study and the DaQing Diabetes Prevention Outcome study
Reaching prediatbetes remission is linked to a decades-long benefit, halving the risk of cardiovascular death or hospitalisation for heart failure in diverse populations. Targeting remission might rep...
www.thelancet.com
December 13, 2025 at 12:43 AM
Faculty at OHSU, UIowa, UCSF, UW–Madison, and VCU: Your next amazing mentee could be one 10‑minute conversation away. PROPEL Virtual Matchmaking Event is Jan 30: 9–1 PT. Faculty registration deadline extended to 5pm PT on Wed Dec 10: propelscholars.org/matchmaking-...
December 8, 2025 at 10:22 PM
Reposted by Ryan Hernandez
"Prebunking works by exposing people to the techniques used to create misleading arguments before they encounter them in the wild."
December 7, 2025 at 5:56 PM
Amazing to be at the #CAGI7 conference. As a data PRODUCER, no less! Fascinating discussions about variants of unknown significance, and how to get rid of them. Sad they are almost always acronymized as VUS, and only once was it VOUS.
December 7, 2025 at 4:46 PM
Reposted by Ryan Hernandez
My quote of the day

The probability that we may fail in the struggle ought not to deter us from the support of a cause we believe to be just.

Abraham Lincoln
December 7, 2025 at 10:18 AM
Reposted by Ryan Hernandez
A study on 1.7 million people in Hong Kong shows superior hybrid immunity to Covid in people who got vaccinated before infection vs. people who got infected first. "Our findings are a direct rebuttal to arguments for natural immunity," the authors write. doi.org/10.1016/j.va...
Redirecting
doi.org
December 6, 2025 at 5:02 PM
Reposted by Ryan Hernandez
Did you publish with researchers outside your lab during grad school? Or published as faculty with a student not under your supervision?

I’m collecting examples of cross-lab collaboration in graduate training.

Please share your experience & this post!

Repository: bit.ly/4pT66BE
December 6, 2025 at 8:05 PM
Reposted by Ryan Hernandez
The era of coding agents is here. How do we approach this as scientists?

Wednesday Dec 10th at 9am PT I'll livestream an interactive demo of what I have learned (matsen.group/agentic.html) about how to leverage agentic coding to do rigorous science.

www.youtube.com/watch?v=Rbhs...
Agentic Coding for Scientists (Dec 2025 edition)
YouTube video by Erick Matsen
www.youtube.com
December 2, 2025 at 6:57 PM
"I love Slate! Everything is so intuitive and seamless!!"
- No grad program director or program manager I've ever met...

For those who attempted to submit your apps to PhD programs and have gotten strange errors, my apologies for the added stress... Folks are working hard to resolve issues!! 🤞🏽
December 2, 2025 at 8:38 PM
Reposted by Ryan Hernandez
I have a new preprint demonstrating a genome-architecture-aware approach to inferring species trees and introgression landscapes from a small number of genomes. If you are interested in phylogenomics, birds, or hybridization, this is for you! www.biorxiv.org/content/10.1...
December 1, 2025 at 7:35 PM
Reposted by Ryan Hernandez
It's the home stretch teaching undergrad Evolutionary Genetics with @aneil-agrawal.bsky.social using my Primer of Mol Pop Gen text! Grateful it's free for all 67 of our students courtesy @uoftlibraries.bsky.social LMK if you use it and suggestions for improvements! global.oup.com/academic/pro...
November 25, 2025 at 7:45 PM
Reposted by Ryan Hernandez
Reminder to everyone - mental health issues and depression generally do not just magically go away - it is important to be vigilant if you or ones you love have or are going through such issues www.espn.com/nfl/story/_/...
Records: WMU police called twice to aid Kneeland
Western Michigan University police were twice called to perform welfare checks on former Cowboys defensive end Marshawn Kneeland while he played for the school.
www.espn.com
November 22, 2025 at 2:30 AM
Reposted by Ryan Hernandez
I wrote a little bit about the "missing heritability" question and several recent studies that have brought it to a close. A short 🧵
The missing heritability question is now (mostly) answered
Not with a bang but with a whimper
theinfinitesimal.substack.com
November 21, 2025 at 10:34 PM