xanthophores

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Pacific Tree frog

The Pacific tree frog (Pseudacris regilla), also known as the Pacific chorus frog, has a range from the West Coast of the United States (from Northern California, Oregon, and Washington) to British Columbia in Canada and extreme southern Alaska. They occur in shades of greens or browns and can change colors over periods of hours and weeks. A rare, recessive “blue morph” is known. This mutation might inhibit the xanthophores’ ability to produce yellow pigments, thus the normally green frog appears blue.

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anonymous asked:

What's the difference between an animal being leucistic and albino? What causes it, I mean. I know leucistic animals can have eyes that aren't pink but I'm not sure why. Also isn't there a type of albinism that doesn't affect the eyes? If so, how can you tell that apart from a leucistic animal?

there are a bunch of differences!

One is that albinism leaves you with a body that has melanocytes but doesn’t produce any melanin. The bits are there, but nothing is working.

In leucism there are not melanocytes to be found. Which also relates us to the next difference: complete leucism doesn’t have any sort of pigment in the affected body parts. It’s snow white. Albinos don’t do that. See, in albinos, only the melanin isn’t happening. If you’re looking at any animal species that has something else, say xanthophores (they contain a yellow pigment) you don’t get snowwhite, you get a yellow. You know those yellow ball pythons? Those are genuine albinos, they  don’t have any melanin in them. But since they have other pigments, they’re not white. 

Now onto the eye difference, that one’s actually funky to explain because fetal development is weird my dude.

Ok, so the vast majority of your melanin producing cells stem from your neural crest. The neural crest is a cell grouping that you get during fetal development. Over times, the cells of the neural crest specify into all sorts of things: melanocytes (eyyyy), cranial cartilage/bone, peripheral nerves + glia and a bunch of other stuff. The melanocytes in the eyes however come from the neural tube. That’s a different bit of fetus that later turns into the central nervous system, and importantly here, your retina. So if the cells that come from the neural tube have melanocytes you get eye colors.

Whereas in albinism it doesn’t matter if there are melanocytes present anywhere because they don’t do their job of producing any melanin. 

Since the melanocytes in skin and eye have different origins, there is a chance that the eyes ones manage to dodge out of the mutations that cause leucism. another result of that is piebald patterning. In piebald patterning you have some cells that have melanocytes and working melanin and some that don’t so you get bigger or smaller patches of normally colored animal and then some bits that are just white. 

Got a closeup of some Doryteuthis pealeii hatchlings!  Chromatophores are the cells responsible for the color changing camouflage in cephalopods. You can see that one of the hatchlings has the chromatophores on its head activated, showing yellow (xanthophores) and maroon pigment (erythrophores), while the other squid has inactive chromatophores (dark dots).

For more information on chromatophores, you can watch my former mentor Roger Hanlon go into much more detail on youtube here!