Sasha Gusev
@sashagusevposts.bsky.social
6.4K followers 680 following 770 posts
Statistical geneticist. Associate Prof at Dana-Farber / Harvard Medical School. www.gusevlab.org
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sashagusevposts.bsky.social
Yeah I don't really get it. The hard part is getting the genetic estimates so running this across many other 23andme traits (even restricting to non-controversial traits) would have been very informative. Perhaps they're going to follow up with more detailed linkage analyses?
sashagusevposts.bsky.social
You can estimate the total genetic difference between populations without having to know the underlying causal variants. You don't get the mechanism and you still have to make strong assumptions on GxE and ascertainment, but IMO an effective way to prioritize traits for follow-up.
sashagusevposts.bsky.social
Interesting evidence for genetics explaining disparities in T2D. Previous work identified a Neanderthal introgressed haplotype common to Native American ancestry with a large effect on T2D (pmc.ncbi.nlm.nih.gov/articles/PMC...). Wonder if there's power to look at archaic admixture here.
shaicarmi.bsky.social
Brilliant paper by Visscher et al.

Populations differ in traits/disease burden. Are these differences due to genetics?

Comparing single variants or polygenic scores between populations is biased due to environmental confounders correlated with the variants.

1/3

www.medrxiv.org/content/10.1...
Direct effect of genetic ancestry on complex traits in a Mexican population
Human populations differ in disease prevalences and in average values of phenotypes, but the extent to which differences are caused by genetic or environmental factors is unknown for most complex trai...
www.medrxiv.org
Reposted by Sasha Gusev
shaicarmi.bsky.social
Brilliant paper by Visscher et al.

Populations differ in traits/disease burden. Are these differences due to genetics?

Comparing single variants or polygenic scores between populations is biased due to environmental confounders correlated with the variants.

1/3

www.medrxiv.org/content/10.1...
Direct effect of genetic ancestry on complex traits in a Mexican population
Human populations differ in disease prevalences and in average values of phenotypes, but the extent to which differences are caused by genetic or environmental factors is unknown for most complex trai...
www.medrxiv.org
Reposted by Sasha Gusev
sashagusevposts.bsky.social
Yes, exactly, the idea was to overload the cells with many perturbations and then estimate components of higher-order interactions GREML-like. But we couldn't get enough cells with multiple edits and only had power to look at module interactions.

www.nature.com/articles/s41...
Scalable genetic screening for regulatory circuits using compressed Perturb-seq - Nature Biotechnology
Compressed Perturb-seq incorporates compressed sensing to genetic screening for scalable discovery of genetic interactions.
www.nature.com
sashagusevposts.bsky.social
We were hoping to look at this in perturb-seq data, but very hard to get the number of combinatorial effects needed for statistical power.
Reposted by Sasha Gusev
sashagusevposts.bsky.social
I think about this every time I shave:
Reposted by Sasha Gusev
michelnivard.bsky.social
I wrote about a rare genetic variant (a CNV) that appears to reduce the risk of schizophrenia diagnosis by ~5x, and why that's not as unambigously amazing as it sounds, but potentially still a pretty big deal.
Its probably nothing, but if it is...
A rare copy number variant appears to significantly reduce the risk of schizophrenia.
open.substack.com
sashagusevposts.bsky.social
very relevant, thank you!
sashagusevposts.bsky.social
That's a great idea, and looks something like the below. I'm working on the size scaling a bit more to convey the point more clearly
sashagusevposts.bsky.social
Yeah I was thinking about this initially and unable to find any examples in the literature where epistasis tagged by additivity versus "pure" additivity mattered. I think the response really is just about narrow-sense h2 (as in the Breeder's Equation).
sashagusevposts.bsky.social
Great mini thread here on lessons for GxG and GxE from non-human organisms:
sashagusevposts.bsky.social
Yeah, uncentered effects make more sense to me biologically but of course you could design a statistical generative model where the interaction is purely non-additive.
sashagusevposts.bsky.social
great commentary article (and thanks for the thread!)
Reposted by Sasha Gusev
giacomobignardi.bsky.social
🧵 on cool choices of image headers (and titles) all from @sashagusevposts.bsky.social's Substack
🔗 at the end

'Beneath the surface of the sum'

Genetic interactions may look like the thing they deviate from

Interaction (1964) by Julian Stanczak
Interaction (1964) by Julian Stanczak
sashagusevposts.bsky.social
Yeah, in general multi component models will only take the part of the interaction that is not captured by additivity. The twin ADE model partitions them correctly but ONLY if there's no shared environment (and other assumptions hold).
sashagusevposts.bsky.social
Sure thing, see this gist. Note that this is always the affect allele frequency and not the minor allele frequency and there's no genotype scaling. Let me know if you think there's a better presentation.
simple epistasis model
simple epistasis model. GitHub Gist: instantly share code, notes, and snippets.
gist.github.com
sashagusevposts.bsky.social
Everyone is free to make their own choices, but I personally think what platform you use has negligible impact on the influence of wealthy and powerful people in the US, and far far less than being heard on important topics.
sashagusevposts.bsky.social
:) I still post on twitter as well
sashagusevposts.bsky.social
So the mystery remains. It is tempting to conclude that biological epistasis is widespread but mostly gets mapped to statistical additivity. But that does not explain the deviations from additivity often observed in twins. /x
sashagusevposts.bsky.social
There is no statistical power to identify individual rare var interactions. But interactions between rare variants and common polygenic scores can be tested and show ... nothing. This is genuinely surprising: large deleterious effects simply add up with common polygenic burden.