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
My daughter Maya, who had to wear a scoliosis brace for 2 years, wants to connect with other teens who live with invisible diseases. www.under-the-iceberg.com/about
About | Who We Are — Under the Iceberg
Learn about Under the Iceberg, a youth organization dedicated to nurturing future leaders through education and growth. Contact us to join or collaborate.
www.under-the-iceberg.com
February 12, 2026 at 3:45 AM
My daughter Maya, who had to wear a scoliosis brace for 2 years, wants to connect with other teens who live with invisible diseases. www.under-the-iceberg.com/about
Reposted by Ryan Hernandez
“Success in US science has come from sustained funding and welcoming the best talent from around the world, yet both of these advantages are in decline”
www.science.org/doi/10.1126/...
www.science.org/doi/10.1126/...
China turns the tables in biotech
For at least a century, major scientific research initiatives have reliably occurred in the United States, usually in response to geopolitical competition. This helped establish the country’s status a...
www.science.org
February 11, 2026 at 12:03 PM
“Success in US science has come from sustained funding and welcoming the best talent from around the world, yet both of these advantages are in decline”
www.science.org/doi/10.1126/...
www.science.org/doi/10.1126/...
Reposted by Ryan Hernandez
We are in the middle of MCB graduate admissions interviews. It has renewed my sense of hope—there are so many bright, empathic and resilient young people ready to help advance knowledge and make a difference.
February 4, 2026 at 5:27 PM
We are in the middle of MCB graduate admissions interviews. It has renewed my sense of hope—there are so many bright, empathic and resilient young people ready to help advance knowledge and make a difference.
Reposted by Ryan Hernandez
It took scientists 11 years to compute 1-2/3=1/3
February 4, 2026 at 8:52 PM
It took scientists 11 years to compute 1-2/3=1/3
Reposted by Ryan Hernandez
Balancing selection alert!! 🧬🧪
New preprint where we try to quantify how likely (or rather, unlikely) it is for balancing selection to maintain stable polymorphism, and how easy (or rather, challenging) it is to identify its signatures in genomes.
#Popgen #MolecularEvolution #EvoBio #Science
New preprint where we try to quantify how likely (or rather, unlikely) it is for balancing selection to maintain stable polymorphism, and how easy (or rather, challenging) it is to identify its signatures in genomes.
#Popgen #MolecularEvolution #EvoBio #Science
A new preprint from the lab, with postdoc @deboraycb.bsky.social and collaborators @aidaandres.bsky.social and Tim Connallon:
“Characterising the detectable and invisible fractions of genomic loci under balancing selection”
www.biorxiv.org/content/10.6...
“Characterising the detectable and invisible fractions of genomic loci under balancing selection”
www.biorxiv.org/content/10.6...
www.biorxiv.org
January 21, 2026 at 4:11 PM
Balancing selection alert!! 🧬🧪
New preprint where we try to quantify how likely (or rather, unlikely) it is for balancing selection to maintain stable polymorphism, and how easy (or rather, challenging) it is to identify its signatures in genomes.
#Popgen #MolecularEvolution #EvoBio #Science
New preprint where we try to quantify how likely (or rather, unlikely) it is for balancing selection to maintain stable polymorphism, and how easy (or rather, challenging) it is to identify its signatures in genomes.
#Popgen #MolecularEvolution #EvoBio #Science
Reposted by Ryan Hernandez
A new preprint from the lab, with postdoc @deboraycb.bsky.social and collaborators @aidaandres.bsky.social and Tim Connallon:
“Characterising the detectable and invisible fractions of genomic loci under balancing selection”
www.biorxiv.org/content/10.6...
“Characterising the detectable and invisible fractions of genomic loci under balancing selection”
www.biorxiv.org/content/10.6...
www.biorxiv.org
January 21, 2026 at 3:32 PM
A new preprint from the lab, with postdoc @deboraycb.bsky.social and collaborators @aidaandres.bsky.social and Tim Connallon:
“Characterising the detectable and invisible fractions of genomic loci under balancing selection”
www.biorxiv.org/content/10.6...
“Characterising the detectable and invisible fractions of genomic loci under balancing selection”
www.biorxiv.org/content/10.6...
Reposted by Ryan Hernandez
Hey MD/PhD-bound Scholars 👋 Prepare for MSTP Program applications with PROPEL! This is an opportunity you don't want to miss!
📆 Feb 6 – Sign up for AMCAS essay reviews by MSTP grad students (QR code)
📆 Feb 13 – Submit essay draft for review
📆 Feb 20 – Receive Feedback
📆 Feb 6 – Sign up for AMCAS essay reviews by MSTP grad students (QR code)
📆 Feb 13 – Submit essay draft for review
📆 Feb 20 – Receive Feedback
January 30, 2026 at 10:46 PM
Hey MD/PhD-bound Scholars 👋 Prepare for MSTP Program applications with PROPEL! This is an opportunity you don't want to miss!
📆 Feb 6 – Sign up for AMCAS essay reviews by MSTP grad students (QR code)
📆 Feb 13 – Submit essay draft for review
📆 Feb 20 – Receive Feedback
📆 Feb 6 – Sign up for AMCAS essay reviews by MSTP grad students (QR code)
📆 Feb 13 – Submit essay draft for review
📆 Feb 20 – Receive Feedback
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.
*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
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.
*Disclosure: I am required to say it's the best conference because it is and I told my mom I wouldn't lie.
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.
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
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.
Registration is free. We will cover travel and lodging for graduate students, and at least partially subsidize those costs for postdocs and assistant professors.
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...
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
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...
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...
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
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
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
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
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
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
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...
www.nytimes.com/2026/01/02/s...
January 2, 2026 at 4:30 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...
www.nytimes.com/2026/01/02/s...
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-...
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
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-...
substack.com/home/post/p-...
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...
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
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...
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...
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...
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
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...
www.nature.com/articles/s41...
Reposted by Ryan Hernandez
What a beautiful paper! 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 6:18 PM
What a beautiful paper! www.nature.com/articles/s41...
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...
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
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...
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...
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...
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
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...
www.thelancet.com/journals/lan...
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
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-...
Reposted by Ryan Hernandez
"Prebunking works by exposing people to the techniques used to create misleading arguments before they encounter them in the wild."
Finland has emerged as a global leader in countering “fake news”. Here's how they've done it
Teaching when to trust
As fake news accelerates, we need to teach our children how to think critically. Finnish schools are leading the charge
newhumanist.org.uk
December 7, 2025 at 5:56 PM
"Prebunking works by exposing people to the techniques used to create misleading arguments before they encounter them in the wild."
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
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.
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
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
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
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
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
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...