I would just add that it’s a gradient of transcription factor(s), proteins that regulate production of other proteins. Some of the regulated proteins are other thranscription factors that create finer gradients, like repeated stripes of gradients. along the initial, single gradient. This can be repeated on multiple levels so that pretty much every point of the body has unique combination of transcription factors. This combination triggers all the other proteins, including structural that create the form of the body. and of course, all this doesn’t just happen in 3D, but also changes with time. It’s complicated.
For illustration and possible direction for some particular interesting cases wrapped in a very entertaining package, I recommend this: www.youtube.com/watch?v=ydqReeTV_vk
This is something I always wondered because some people have a bunch of theories about whether your head should face north or south or whatever, because of the earth magnetic field. Is there any science in this or just “superstition”?...
That’s a strong claim you’ve got there. It seems humans do possess some amount of magnetoreception, there’s even a suggested mechanism. It might be jammed by certain radiofrequencies, although I don’t know if they are still in use. Some other mammals have been shown to sense magnetism too. Personally, when I’m in a bed, especially a new one, I feel my rotation relative to my normal bed. It isn’t very precise and it’s difficult to test, so I can’t be entirely sure, but that’s how it feels. I don’t know about any studies relating magnetism and sleep. I know there historically were people who claimed it matters to them, but I think that unless you already know that it matter to you, it probably doesn’t. I’d say that much more important is darkness. Also, I heard people feel better with feet towards the door, but I don’t know if it’s proven in any way.
I wonder why I’m being downvoted. I very much welcome discussion. If you want to tell me why I’m wrong, like that cryptochromes cannot be used in sensing magnetic field upon closer look etc., I’d be excited. Disagreement without pointing out any mistakes I did brings me nothing.
If it’s just disbelief, I would’ve preferred being asked for sources. Even wikipedia mentions some of what I wrote (en.m.wikipedia.org/wiki/Magnetoreception) and while I admit my source isn’t primary literature, it is a monography about senses and I would’ve made an effort to track down at least some of the original papers.
I actually don’t know, it’s a good point. It’s definitely stochastic, but I don’t know how late in the development it happens. There are definitely cats with colours completely jumbled cats with large patches of each colour. But I just realised that colour comes from melanocytes. And melanocytes must migrate from the back, as they come from neural crest. Which strikes me as a great reason for straight division on the front (the cells coming from left and right meet there) that we see here, regardless of the origin of diversity of cell colours. So I think it shouldn’t matter, but it’s just a guess.
How do different body parts (specifically shape) emerge from our genes?
I am creating a simulation to evolve simple, multi-cell organisms. (Just for fun!)...
Is there any scientific study about where should the bed be facing?
This is something I always wondered because some people have a bunch of theories about whether your head should face north or south or whatever, because of the earth magnetic field. Is there any science in this or just “superstition”?...
The littlest chimera ( lemmy.world )