@JonAMichaels @casa_tuthill @JAlGallego This is really beautiful work! On the degree of precision, the underlying principle is that encoding of the arborisation pattern should be as precise as it needs to be, but no more so
@JonAMichaels @casa_tuthill @JAlGallego If the genome can encode some guidance and branching rules that get the axons or dendrites in generally the right place to meet the right partners, that's usually good enough
@JonAMichaels @casa_tuthill @JAlGallego Nicely reviewed by @bassemh1 + Hiesinger here: Beyond Molecular Codes: Simple Rules to Wire Complex Brains cell.com/cell/fulltext/… 
@JonAMichaels @casa_tuthill @JAlGallego @bassemh1 That leaves loads of scope for random variability in branching of individual cells. For most cells, this won't have any impact on anything... but sometimes it will...
@JonAMichaels @casa_tuthill @JAlGallego @bassemh1 As described here: A neurodevelopmental origin of behavioral individuality biorxiv.org/content/10.110…
@JonAMichaels @casa_tuthill @JAlGallego @bassemh1 Interestingly, the degree of randomness can itself be a genetic trait... As mutations arise or are introduced affecting the developmental rules, variability tends to increase...
@JonAMichaels @casa_tuthill @JAlGallego @bassemh1 When played out across the whole nervous system, such variability can sometimes have outsized, cascading effects on the eventual phenotype, due to the contingent and non-linear nature of developmental processes
@JonAMichaels @casa_tuthill @JAlGallego @bassemh1 All of which means that individuals with the same genome will not have identical brains and this variation is a likely source of the "non-shared environment" effects on psychological traits in humans, as discussed in INNATE 😊press.princeton.edu/books/hardcove…
@JonAMichaels @casa_tuthill @JAlGallego @bassemh1 Or, if you prefer it in talk form: How the Wiring of Our Brains Shapes Who We Are - with Kevin Mitchell via @YouTube
