so are hox genes just the ones that actually code for bodily structures?
do other genes just exist to tell the hox genes when, where and how to be expressed?
>inb4 homework thread
no, just interested
so are hox genes just the ones that actually code for bodily structures?
b
sex genes
Was giving the Pepe colour scheme intentional in this pic?
Um.. are hox genes why there can never be vertebrate hexapods?
So you can never have a dragon with four legs and two wings; it always has to be two legs and two wings?
as I understand it the problem is vertebrates have multiple redundant copies of the hox genes, so to get say a new set of limbs you'd need to disable more than just one or two genes. Something like 16 or 20 would have to be knocked out or replicated.
that's not likely to happen by chance. and if it did the animal would die.
Vertebrate hexapods can't happen because the limbs are located on for lack of a better term "unique" segments (the one linking the head to the body, and the one constituting the base of the torso).
There's no material to insert another pair of limbs, which requires a segment, which in vertebrates can't be constructed from these two.
You can of course help with gene engineering -- and defeat the point of interest.
Also before you ask, snakes astonishingly do not represent an extensively segmented vertebrate, but rather an comically elongated ribcage.
3/3
There are, however, still a few exceedingly oblique, lateral avenues how you could get a hexapod from a circa 2023 AD vertebrate genetic and physiological base. The most promising such concerns the tail: the tail represents a unit that, unlike segments, CAN be duplicated. A stable mutation for a duplicated or bifurcated tail could serve as basis by which these tails take (especially in arboreal animals) on more grasping and other manipulative/tactile jobs (i.e. their use as a surface contacting and even load bearing organ is established). These duplicated prehensile tails could eventually wander more to the sides of the body plan, and optionally via chance come to resemble hands or feet. The "hands" variant would look especially alien, as the handed limb would be the one at the bottom end of the torso.
Many orders of magnitudes less likely is a scenario where by pure chance, exaggerated features or mutation-derived outgrowths stabilize. In a next step, these outgrowths can be adapted for novel tasks vaguely related to manipulation or locomotion. Both of these required steps don't offer any incremental gain in fitness, and can be achieved only via a series of pure chance. I guess an exaggerated pair of ribs would offer the only such viable scenario, rather than hoping some fleshy growth randomly develops a connected bone structure.
i am unintelligent and require diagrams.
Genes don't determine morphology
superior hypothesis
so how do you deal with the fact that meddling with genes changes morphology?
what do you propose determines morphology.
are you a muslim?
You're working within an obsolete and reductive paradigm. Look into bioelectric networks
bioelectricity is only responsible for a minuscule amount of morphology and even that works partly through the genome
Hox genes determine the position of the limbs, organs, etc in the anteroposterior axis.
>Back legs are actually the middle legs
Fuck flies
You've got it backwards: Hox genes regulate the expression of other genes. If you fuck around with them, you can create fruit flies with legs instead of antennae and other freaky shit.
so hox genes are genes near the top of a genetic circuit and they determine the intensity, location ect. of genes that fall in its domain?
so tinman isnt really responsible for making hearts "from scratch" as it is responsible for just activating and deactivating the hundreds of components that make the structure?
>so tinman isnt really responsible for making hearts "from scratch" as it is responsible for just activating and deactivating the hundreds of components that make the structure?
these aren't two different things. False dichotomy.
the process is much more complicated than you imagine. tinman does both. It creates hearts from scratch by differentiating, producing, and activating cardiac progenitor cells.
i understand now, thank you anon