You'd expect phenotypic variance to be lower in inbred strains cuz genetic variance (Vg) = zero.
But because they are inbred (homozygous at all alleles) the ability of cellular systems to buffer noise or environmental fluctuations may be much lower
This means that the non-genetic sources of variance (here called Ve, but not necessaarily "environmental") may be much higher:
Homozygosity is BAD! (Not just cuz of specific deleterious recessive effects, but generally for the robustness of the whole system)
This has parallels in the slightly increased variance of males > females for all kinds of traits, most likely due to hemizygosity (having only one copy) of the X chromosome
Making the entire genome homozygous should have correspondingly larger effects on variance
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Cog/comp neuro folks: is there a mechanism that an organism can draw on to increase the randomness in the ideas that "occur to it" as possible actions in a given situation?
If an organism is frustrated in its goals or faced with no good options, can it (~choose to) dial up cognitive "exploration" to expand the action search space?
Are any such neural mechanisms known? (e.g., acetylcholine signals of arousal...?) (cc @DrYohanJohn re Grossbergian "arousal" signals)
I did find the idea (from @mh_lab) that some individual *synapses* may be innate and others learned confusing. Does that refer to the existence of the connection or its weight?
In my view, polygenic scores are a statistical tool, not one with adequate precision in individuals to warrant use in embryo selection.
It is true that those in the very highest PGS deciles for some complex diseases have significantly higher risk than the population average. But any such embryos will also have sibling embryos with higher than average PGS...
How Mathematical ‘Hocus-Pocus’ Saved Particle Physics quantamagazine.org/how-renormaliz… - on the "renormalization group" as a means of traversing scales...
Question: is renormalization just a handy mathematical tool to enable calculations to be done at higher scales (by truncating sums that tend towards infinity OR= averaging over small-scale parameters at some grid size)?
Or is this how nature itself works? Is there real coarse-graining across levels that grants a degree of genuinely level-specific causality? (Contra reductionism) cc @C4COMPUTATION
I mean, these could be very reliable findings. But they rest on some major assumptions: 1. that psychopathy is at the level of brain a single thing. 2. that the analyses included in the met-analysis are not biased at all...
...and 3. that the size of different brain regions is relatable to (and explains differences in) complex psychological functions like moral reasoning
How a ‘fatally, tragically flawed’ paradigm has derailed the science of obesity statnews.com/2021/09/13/how… - is obesity due to over-eating or dysregulated fat storage? cc @StephenORahilly
One point not commented on in article is that genes implicated in obesity (through rare or common variants) are enriched for nervous system expression and function...
Do these regulate appetite (many clearly do) or brain mechanisms controlling fat metabolism? Or both?