Travis Mallard
@wakeworksleep.bsky.social
asst prof | clinical psychologist | some sort of geneticist | not a neuroscientist | mass general & harvard med | engagement ≠ endorsement
Reposted by Travis Mallard
Join us in New Haven!
August 19, 2026 at 7:54 PM
Join us in New Haven!
Reposted by Travis Mallard
Pleased to share our new preprint: "Mapping the genetic architecture of human cortical expansion and its links to neuropsychiatric disorders" www.biorxiv.org/content/10.6...
Mapping the genetic architecture of human cortical expansion and its links to neuropsychiatric disorders
Cortical expansion is a defining feature of human evolution and neurodevelopment, involving the tangential growth and gyrification of the cerebral cortex. Although disruptions to the expansion of the ...
www.biorxiv.org
July 17, 2026 at 3:15 PM
Pleased to share our new preprint: "Mapping the genetic architecture of human cortical expansion and its links to neuropsychiatric disorders" www.biorxiv.org/content/10.6...
Reposted by Travis Mallard
(10/15) Importantly, genome-wide genetic correlation only told part of the story.
Using MiXeR, we found extensive shared polygenic architecture with many disorders—even when overall genetic correlation was small or absent.
Using MiXeR, we found extensive shared polygenic architecture with many disorders—even when overall genetic correlation was small or absent.
July 17, 2026 at 3:15 PM
(10/15) Importantly, genome-wide genetic correlation only told part of the story.
Using MiXeR, we found extensive shared polygenic architecture with many disorders—even when overall genetic correlation was small or absent.
Using MiXeR, we found extensive shared polygenic architecture with many disorders—even when overall genetic correlation was small or absent.
Reposted by Travis Mallard
(5/15) We then performed a multivariate GWAS of this cortical expansion factor.
This identified:
🧬 48 genomic loci
🧬 30 effector genes
🧬 Multiple novel associations that were not genome-wide significant in any individual imaging phenotype.
This identified:
🧬 48 genomic loci
🧬 30 effector genes
🧬 Multiple novel associations that were not genome-wide significant in any individual imaging phenotype.
July 17, 2026 at 3:15 PM
(5/15) We then performed a multivariate GWAS of this cortical expansion factor.
This identified:
🧬 48 genomic loci
🧬 30 effector genes
🧬 Multiple novel associations that were not genome-wide significant in any individual imaging phenotype.
This identified:
🧬 48 genomic loci
🧬 30 effector genes
🧬 Multiple novel associations that were not genome-wide significant in any individual imaging phenotype.
Pleased to share duckmapR, an R package offering perceptually uniform, CVD-accessible color maps inspired by my namesake 🦆
This started as a bit of a joke but turned into a fun (multi-)weekend project. Check it out at travismallard.github.io/duckmapR/!
This started as a bit of a joke but turned into a fun (multi-)weekend project. Check it out at travismallard.github.io/duckmapR/!
July 13, 2026 at 8:42 PM
Pleased to share duckmapR, an R package offering perceptually uniform, CVD-accessible color maps inspired by my namesake 🦆
This started as a bit of a joke but turned into a fun (multi-)weekend project. Check it out at travismallard.github.io/duckmapR/!
This started as a bit of a joke but turned into a fun (multi-)weekend project. Check it out at travismallard.github.io/duckmapR/!
Reposted by Travis Mallard
1/9 🚨 BREAKING OUT OF STEALTH MODE 🚨
Multivariate GWAS in Genomic SEM now runs on a laptop!
New preprint + package update: a closed-form analytic solution makes multivariate GWAS ~800× faster, cutting runtimes from hours on HPC clusters to minutes on a personal computer.
Multivariate GWAS in Genomic SEM now runs on a laptop!
New preprint + package update: a closed-form analytic solution makes multivariate GWAS ~800× faster, cutting runtimes from hours on HPC clusters to minutes on a personal computer.
The Predator Emerges
ALT: The Predator Emerges
static.klipy.com
June 5, 2026 at 2:04 PM
1/9 🚨 BREAKING OUT OF STEALTH MODE 🚨
Multivariate GWAS in Genomic SEM now runs on a laptop!
New preprint + package update: a closed-form analytic solution makes multivariate GWAS ~800× faster, cutting runtimes from hours on HPC clusters to minutes on a personal computer.
Multivariate GWAS in Genomic SEM now runs on a laptop!
New preprint + package update: a closed-form analytic solution makes multivariate GWAS ~800× faster, cutting runtimes from hours on HPC clusters to minutes on a personal computer.
Reposted by Travis Mallard
We are pleased to announce the release of FinnGen DF13 results! 🧬
While the number of participants remains unchanged, DF13 incorporates updated health register data, increasing the number of cases across most disease endpoints.
Browsing & download instructions here: www.finngen.fi/en/access_re...
While the number of participants remains unchanged, DF13 incorporates updated health register data, increasing the number of cases across most disease endpoints.
Browsing & download instructions here: www.finngen.fi/en/access_re...
June 3, 2026 at 7:26 AM
We are pleased to announce the release of FinnGen DF13 results! 🧬
While the number of participants remains unchanged, DF13 incorporates updated health register data, increasing the number of cases across most disease endpoints.
Browsing & download instructions here: www.finngen.fi/en/access_re...
While the number of participants remains unchanged, DF13 incorporates updated health register data, increasing the number of cases across most disease endpoints.
Browsing & download instructions here: www.finngen.fi/en/access_re...
Reposted by Travis Mallard
Interested in applying multi-omics imputation or TWAS/PWAS approaches to your data? Frustrated by the models being spread across multiple resources? Enter OmicsPred: a centralised resource for genetic prediction of multi-omic traits!
🔗 : www.omicspred.org
📃 : www.medrxiv.org/content/10.6...
🔗 : www.omicspred.org
📃 : www.medrxiv.org/content/10.6...
May 20, 2026 at 10:44 AM
Interested in applying multi-omics imputation or TWAS/PWAS approaches to your data? Frustrated by the models being spread across multiple resources? Enter OmicsPred: a centralised resource for genetic prediction of multi-omic traits!
🔗 : www.omicspred.org
📃 : www.medrxiv.org/content/10.6...
🔗 : www.omicspred.org
📃 : www.medrxiv.org/content/10.6...
Reposted by Travis Mallard
🧬 New preprint! We present an All by All analysis in All of Us: common and rare variant association testing across 392,030 whole genomes and 3,602 phenotypes. 1.337 trillion tests, ~50k significant signals, all publicly browseable. www.medrxiv.org/content/10.6...
Systematic common and rare variant association testing in 392,030 whole genomes in All of Us
Large-scale genome-wide association studies (GWAS) and rare variant association studies (RVAS) from population biobanks provide valuable resources for gene discovery in complex human traits. We presen...
www.medrxiv.org
May 13, 2026 at 1:10 PM
🧬 New preprint! We present an All by All analysis in All of Us: common and rare variant association testing across 392,030 whole genomes and 3,602 phenotypes. 1.337 trillion tests, ~50k significant signals, all publicly browseable. www.medrxiv.org/content/10.6...
Reposted by Travis Mallard
Don't be shy to take on a little two-week side project. These five months will be the most precious three years of your academic journey.
April 20, 2026 at 6:48 AM
Don't be shy to take on a little two-week side project. These five months will be the most precious three years of your academic journey.
Reposted by Travis Mallard
🚨🚨New work just out by the truly stellar Will Snyder - revealing rare and common genetic influences on complexity of human cortical folding !! 🚨🚨
👀 Will’s thread ⬇️ for deets, and to follow on @willsnyder.bsky.social
Huge congrats to Will & thnx to fabulous collaborators who made this possible.
👀 Will’s thread ⬇️ for deets, and to follow on @willsnyder.bsky.social
Huge congrats to Will & thnx to fabulous collaborators who made this possible.
How may rare vs. common genetic variation separately influence how our brains – and their complex folding patterns – take shape? 🧬 🧠
Check out our new preprint (and final work from my PhD!) out now! ( + thread below) www.biorxiv.org/content/10.6...
Check out our new preprint (and final work from my PhD!) out now! ( + thread below) www.biorxiv.org/content/10.6...
www.biorxiv.org
March 9, 2026 at 10:01 PM
🚨🚨New work just out by the truly stellar Will Snyder - revealing rare and common genetic influences on complexity of human cortical folding !! 🚨🚨
👀 Will’s thread ⬇️ for deets, and to follow on @willsnyder.bsky.social
Huge congrats to Will & thnx to fabulous collaborators who made this possible.
👀 Will’s thread ⬇️ for deets, and to follow on @willsnyder.bsky.social
Huge congrats to Will & thnx to fabulous collaborators who made this possible.
Reposted by Travis Mallard
4/ With such a large and diverse sample, we identified many genes associated with externalizing: Across 1,294 genomic loci and 647 fine-mapped SNPs, we pinpointed 961 effector genes, including known biology (e.g., CADM2, BDNF) and novel discoveries (e.g., SLC17A6, NRN1)!
February 11, 2026 at 10:33 AM
4/ With such a large and diverse sample, we identified many genes associated with externalizing: Across 1,294 genomic loci and 647 fine-mapped SNPs, we pinpointed 961 effector genes, including known biology (e.g., CADM2, BDNF) and novel discoveries (e.g., SLC17A6, NRN1)!
Reposted by Travis Mallard
Our multi-ancestry GWAS of EXTernalizing conditions (ADHD, substance use...) in ~4M people reveals neurodevelopmental risk, drug-repurposing targets, and yields one of the strongest psychiatric polygenic indices yet! 🧬🎉 doi.org/10.64898/202...
Genomic insights into substance use and disinhibitory disorders
Externalizing spectrum disorders- spanning attention-deficit/hyperactivity disorder, conduct disorder, substance use disorders, and other disorders characterized by disinhibition - frequently co-occur...
doi.org
February 11, 2026 at 10:33 AM
Our multi-ancestry GWAS of EXTernalizing conditions (ADHD, substance use...) in ~4M people reveals neurodevelopmental risk, drug-repurposing targets, and yields one of the strongest psychiatric polygenic indices yet! 🧬🎉 doi.org/10.64898/202...
Reposted by Travis Mallard
Nature research paper: Rare genetic variants confer a high risk of ADHD and implicate neuronal biology
go.nature.com/3LARwjy
go.nature.com/3LARwjy
Rare genetic variants confer a high risk of ADHD and implicate neuronal biology - Nature
An analysis of rare genetic variants identifies three genes—MAP1A, ANO8 and ANK2—that have a role in attention deficit hyperactivity disorder (ADHD) and investigates the potential underlying biological mechanisms.
go.nature.com
November 12, 2025 at 5:40 PM
Nature research paper: Rare genetic variants confer a high risk of ADHD and implicate neuronal biology
go.nature.com/3LARwjy
go.nature.com/3LARwjy
Reposted by Travis Mallard
1/4 Thrilled to be sharing new work published today in Nature describing the third wave of results from the PGC Cross-Disorder Group. This reflects a massive group effort to examine shared and unique genetic signal across >1 million cases for 14 psychiatric disorders. www.nature.com/articles/s41...
Mapping the genetic landscape across 14 psychiatric disorders - Nature
Genomic analyses applied to 14 childhood- and adult-onset psychiatric disorders identifies five underlying genomic factors that explain the majority of the genetic variance of the individual disorders...
www.nature.com
December 10, 2025 at 4:22 PM
1/4 Thrilled to be sharing new work published today in Nature describing the third wave of results from the PGC Cross-Disorder Group. This reflects a massive group effort to examine shared and unique genetic signal across >1 million cases for 14 psychiatric disorders. www.nature.com/articles/s41...
Reposted by Travis Mallard
First time on Bsky and first big announcement!
I am excited to announce that our new study explaining the missing heritability of many phenotypes using WGS data from ~347,000 UK Biobank participants has just been published in @Nature.
Our manuscript is here: www.nature.com/articles/s41....
I am excited to announce that our new study explaining the missing heritability of many phenotypes using WGS data from ~347,000 UK Biobank participants has just been published in @Nature.
Our manuscript is here: www.nature.com/articles/s41....
Estimation and mapping of the missing heritability of human phenotypes - Nature
WGS data were used from 347,630 individuals with European ancestry in the UK Biobank to obtain high-precision estimates of coding and non-coding rare variant heritability for 34 co...
www.nature.com
November 12, 2025 at 5:57 PM
First time on Bsky and first big announcement!
I am excited to announce that our new study explaining the missing heritability of many phenotypes using WGS data from ~347,000 UK Biobank participants has just been published in @Nature.
Our manuscript is here: www.nature.com/articles/s41....
I am excited to announce that our new study explaining the missing heritability of many phenotypes using WGS data from ~347,000 UK Biobank participants has just been published in @Nature.
Our manuscript is here: www.nature.com/articles/s41....
Reposted by Travis Mallard
When do machine learning models actually outperform standard polygenic scores? 🤔
In our new preprint, we benchmark how non-additive genetic effects (i.e, dominance deviations) shape polygenic prediction across simulated and UK Biobank traits.
👉 www.medrxiv.org/content/10.1...
🧵 1/6
In our new preprint, we benchmark how non-additive genetic effects (i.e, dominance deviations) shape polygenic prediction across simulated and UK Biobank traits.
👉 www.medrxiv.org/content/10.1...
🧵 1/6
Benchmarking non-additive genetic effects on polygenic prediction and machine learning-based approaches
Polygenic scores (PGSs) are widely used to translate genome-wide association study (GWAS) findings into tools for genetic risk prediction. Most current approaches assume additive effects, yet the cont...
www.medrxiv.org
October 14, 2025 at 11:14 AM
When do machine learning models actually outperform standard polygenic scores? 🤔
In our new preprint, we benchmark how non-additive genetic effects (i.e, dominance deviations) shape polygenic prediction across simulated and UK Biobank traits.
👉 www.medrxiv.org/content/10.1...
🧵 1/6
In our new preprint, we benchmark how non-additive genetic effects (i.e, dominance deviations) shape polygenic prediction across simulated and UK Biobank traits.
👉 www.medrxiv.org/content/10.1...
🧵 1/6
Reposted by Travis Mallard
Some recent work led by @peterjonghona.bsky.social and myself at @yaleschoolofmed.bsky.social looks at environmental, psychiatric, and genetic predictors of alcohol use disorder.
Online today at The American Journal of Psychiatry (@apapsychiatric.bsky.social):
psychiatryonline.org/doi/10.1176/...
Online today at The American Journal of Psychiatry (@apapsychiatric.bsky.social):
psychiatryonline.org/doi/10.1176/...
September 24, 2025 at 7:34 PM
Some recent work led by @peterjonghona.bsky.social and myself at @yaleschoolofmed.bsky.social looks at environmental, psychiatric, and genetic predictors of alcohol use disorder.
Online today at The American Journal of Psychiatry (@apapsychiatric.bsky.social):
psychiatryonline.org/doi/10.1176/...
Online today at The American Journal of Psychiatry (@apapsychiatric.bsky.social):
psychiatryonline.org/doi/10.1176/...
Reposted by Travis Mallard
I'm looking for a PhD student to do some trailblazing at the frontier of personality genomics and lifespan gene-environment transactions (start Fall 2026)! If you want to work with me: psychology.msu.edu/graduatestud...
(PS @drmeltemyucel.bsky.social is taking a student too, in moral psych/dev!)
(PS @drmeltemyucel.bsky.social is taking a student too, in moral psych/dev!)
September 2, 2025 at 3:57 PM
I'm looking for a PhD student to do some trailblazing at the frontier of personality genomics and lifespan gene-environment transactions (start Fall 2026)! If you want to work with me: psychology.msu.edu/graduatestud...
(PS @drmeltemyucel.bsky.social is taking a student too, in moral psych/dev!)
(PS @drmeltemyucel.bsky.social is taking a student too, in moral psych/dev!)
Reposted by Travis Mallard
Now on CRAN, ggdiagram is a #ggplot2 extension that draws diagrams programmatically in #Rstats. Allows for precise control in how objects, labels, and equations are placed in relation to each other.
wjschne.github.io/ggdiagram/ar...
wjschne.github.io/ggdiagram/ar...
August 20, 2025 at 10:43 AM
Now on CRAN, ggdiagram is a #ggplot2 extension that draws diagrams programmatically in #Rstats. Allows for precise control in how objects, labels, and equations are placed in relation to each other.
wjschne.github.io/ggdiagram/ar...
wjschne.github.io/ggdiagram/ar...
Reposted by Travis Mallard
The field of neuroscience views the goal of human genetics as "finding genes". This is an outdated view. In whole genome studies of rare variants, finding genes is the easy part. The more interesting and important goal is to map out the causal pathway from genes to brain function to cognitive traits
A cross-disorder analysis of CNVs finds novel loci and dose-dependent relationships of genes to psychiatric traits https://www.medrxiv.org/content/10.1101/2025.07.11.25331310v1
July 16, 2025 at 2:47 PM
The field of neuroscience views the goal of human genetics as "finding genes". This is an outdated view. In whole genome studies of rare variants, finding genes is the easy part. The more interesting and important goal is to map out the causal pathway from genes to brain function to cognitive traits
Reposted by Travis Mallard
Excited about our new preprint: 1st successful genome-wide study of >61,000 panic attack and 29,000 panic disorder cases. www.medrxiv.org/content/10.1... We find 17 associations & evidence that peripheral neurons in eye, lungs and heart are involved in panic & other psychiatric disorders 1/n
June 17, 2025 at 10:50 AM
Excited about our new preprint: 1st successful genome-wide study of >61,000 panic attack and 29,000 panic disorder cases. www.medrxiv.org/content/10.1... We find 17 associations & evidence that peripheral neurons in eye, lungs and heart are involved in panic & other psychiatric disorders 1/n
Reposted by Travis Mallard
Examining the sensitivity for environmental influences by conducting a GWAS on differences between identical twins - very clever design!
Out now in @nathumbehav.nature.com : www.nature.com/articles/s41...
Out now in @nathumbehav.nature.com : www.nature.com/articles/s41...
June 10, 2025 at 2:16 PM
Examining the sensitivity for environmental influences by conducting a GWAS on differences between identical twins - very clever design!
Out now in @nathumbehav.nature.com : www.nature.com/articles/s41...
Out now in @nathumbehav.nature.com : www.nature.com/articles/s41...