Jonathan Sebat

Jonathan Sebat

@sebatlab.bsky.social

Psychiatric genetics, complex trait genetics, genome sequencing, rare variants are my jam

2.1K followers810 following203 posts

Jonathan Sebat reposted

Jonathan Sebat reposted

Please repost: we are recruiting a postdoc for a project in my lab on genes and environment in autism

Jonathan Sebat@sebatlab.bsky.social

We are proud to be one of the 13 projects funded by the NIH Autism Data Science Initiative. Our project: "Elucidating the Interplay of Genes and Environment in Autism Using Genomic and Exposure Data from Large Populations" 🧵https://www.nytimes.com/2025/09/26/health/autism-research-trump-kennedy.html

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We will also investigate how environmental factors influence clinical outcome of genes in ASD. Samples of many thousands are needed to identify G. Capturing the effects of GxE requires sample sizes of millions. Juicy preliminary data will be posted soon to medrxiv. It takes a village, come join us!

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Our 2022 paper in NG illustrates one example: the observed association of parental age with ausism consists of a mixture of causal pathway E → de novo mutation → ASD; and noncausal pathway Parental age ← polygenic score → ASD

As a novel approach to causal inference, we will use collider effects to find genetic evidence to SUPPORT a causal role of environmental exposure. If E has a strong effect that is uncorrelated with G in the population, genes will explain LESS of the variance in the explosed group!

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THE major challenge in epidemiological studies of the environment in autism is the pervasive passive correlation of genes and environment (rGE) that happens in the population, also known horizontal pleiotropy. There are causal effects to be found, but we need to separate correlation from causation

We will use a multi-pronged approach to causal inference using data on G and E in >2 million people, including association, MR and GxE exploring the interplay of exposures with rare and common variation that contributes to ASD, and we will rigorously evaluate rGE in family and population

Pfff, big deal. My social media accounts are powered by edibles

T. Greg Doucette@gregdoucette.bsky.social

So you know how there's a running gag about trying to run old school Doom or Wolfenstein on things never intended to run video games? This guy has managed to code a web server that runs from a disposable vape 🤯 bogdanthegeek.github.io/blog/project...

True story, as an undergrad I did an experiment with green Anole lizards where I kept a constant number of flies in their cage by running a hose from my scuba tank through a jar of flies and into the tank. Lizards really are the mothers of invention

Structural variants are significant contributor to autism. But many SVs & TRs are hard to detect with short reads. Long read sequencing with @pacbio.bsky.social and @nanoporetech.com captures and maps out alot of what short reads miss. So what can LR-WGS tell us about autism? 🧵

medRxivpreprint@medrxivpreprint.bsky.social

Long Read Genome Sequencing Elucidates Diverse Functional Consequences of Structural and Repeat Variation in Autism https://www.medrxiv.org/content/10.1101/2025.07.20.25331880v1

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Power is limited in N=243. But the signal is quantifiable. Rare SVs, TRs and rare SNVs combined explained 7.6% of the heritability. We will need larger samples to get precise estimates, but the combined common and rare is starting to reach a substantial fraction.

TL;DR LRs boost detection of de novo and inherited coding SVs and longer TRs, which boosts detection of causal variants. But long reads are game changer WRT to resolving complex genetic variation and its functional consequences and regulatory effects.

Structural variants are significant contributor to autism. But many SVs & TRs are hard to detect with short reads. Long read sequencing with @pacbio.bsky.social and @nanoporetech.com captures and maps out alot of what short reads miss. So what can LR-WGS tell us about autism? 🧵

medRxivpreprint@medrxivpreprint.bsky.social

Long Read Genome Sequencing Elucidates Diverse Functional Consequences of Structural and Repeat Variation in Autism https://www.medrxiv.org/content/10.1101/2025.07.20.25331880v1

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Skewed methylation was a characteristic of all "gray zone" alleles of FMR1 (>35 repeats). But in all but one sample, the skewing was specific to FMR1. X chromosome inactivation was NOT skewed. 10/N

Gray zone carriers typically look like panel E. Only FMR1 methylation is skewed. X chromosome inactivation is not skewed. The one exception (panel D) was a girl that carried an X-linked dominant mutation in DDX3X a gene that escapes XCI and, for unknown reasons, is know to cause skewed XCI

Structural variants are significant contributor to autism. But many SVs & TRs are hard to detect with short reads. Long read sequencing with @pacbio.bsky.social and @nanoporetech.com captures and maps out alot of what short reads miss. So what can LR-WGS tell us about autism? 🧵

medRxivpreprint@medrxivpreprint.bsky.social

Long Read Genome Sequencing Elucidates Diverse Functional Consequences of Structural and Repeat Variation in Autism https://www.medrxiv.org/content/10.1101/2025.07.20.25331880v1

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In the fragile X repeat FMR1, we went full long-read nerd with PHASED repeats AND methylation. Phased reads in one female (REACH365) shows random methylation (red) on the X. In another female (REACH561) with an expanded 49 repeat allele, methylation was totally skewed to expanded haplotype H2 9/N

Structural variants are significant contributor to autism. But many SVs & TRs are hard to detect with short reads. Long read sequencing with @pacbio.bsky.social and @nanoporetech.com captures and maps out alot of what short reads miss. So what can LR-WGS tell us about autism? 🧵

medRxivpreprint@medrxivpreprint.bsky.social

Long Read Genome Sequencing Elucidates Diverse Functional Consequences of Structural and Repeat Variation in Autism https://www.medrxiv.org/content/10.1101/2025.07.20.25331880v1

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Phase information of individual reads ends up being useful for a variety of purposes including assembling SVs, genotyping and detection of de novo and mosaic SVs and TRs (more to come on this) 6/N

Where long reads really shine is when you need to map out and assemble large complex SVs. In doing so, we found a class of duplication/deletion events (TAN-DUP-DEL and INV-DUP-DEL) events. They also produce distinct signatures in short read coverage data

Structural variants are significant contributor to autism. But many SVs & TRs are hard to detect with short reads. Long read sequencing with @pacbio.bsky.social and @nanoporetech.com captures and maps out alot of what short reads miss. So what can LR-WGS tell us about autism? 🧵

medRxivpreprint@medrxivpreprint.bsky.social

Long Read Genome Sequencing Elucidates Diverse Functional Consequences of Structural and Repeat Variation in Autism https://www.medrxiv.org/content/10.1101/2025.07.20.25331880v1

View full thread

Panel C (coding SVs in constrained genes) are a class variants with well-established associations with ASD. To maximize detection of these, one needs a combination of short reads and long reads. For large (>50 bp) tandem repeat variants, long reads alone do a good job 4/N.

De novo SVs have been bread-and-butter of ASD genetics, and LRs detect novel de novo and somatic MOSAIC coding SVs. In this example, a de novo in-frame duplication, was present on most (but not all) reads on the H2 haplotype in the offspring and coverage also showed copy number of 2.5 instead of 3.

Structural variants are significant contributor to autism. But many SVs & TRs are hard to detect with short reads. Long read sequencing with @pacbio.bsky.social and @nanoporetech.com captures and maps out alot of what short reads miss. So what can LR-WGS tell us about autism? 🧵

medRxivpreprint@medrxivpreprint.bsky.social

Long Read Genome Sequencing Elucidates Diverse Functional Consequences of Structural and Repeat Variation in Autism https://www.medrxiv.org/content/10.1101/2025.07.20.25331880v1

We WGS'd 267 subjects from 63 ASD families, 109 with ONT (GridION) and 158 with PacBio HiFi platform (Sequel IIe) and 109 with ONT(GridION). Standard structural variant (SV) and tandem repeat (TR) calling pipelines were applied to both platforms. 2/N

a susbstantial fraction of SVs are only detetable with LRs. However, there is also a significant fraction of SVs that are detectable only with Illumina WGS, particularly large CNVs that are detectable based on coverage. (A) All SVs (B) coding SVs (C) coding SVs in constrained genes (pLI>0.9).