[infodump request] @ActuallyAubrey@void.lgbt what's the deal with eye colors of different animals?
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[infodump request]
@ActuallyAubrey@void.lgbt what's the deal with eye colors of different animals? ik in humans it's a fairly recent mutation -
[infodump request]
@ActuallyAubrey@void.lgbt what's the deal with eye colors of different animals? ik in humans it's a fairly recent mutation@mir actually, humans are relatively unique in the way our eye colors are handled. There are up to 16 different genes currently identified in humans that control various factors relating to eye color, and so eye color is determined largely by your parents' eye colors, creating a variety of different eye colors within the total human population.
In wild animals, eye color is typically consistent within a species. All elephants have brown eyes, for example. The reason for this seems to be because there's no evolutionary advantage to eyes of a different color. If an elephant was born in the wild with blue eyes, for example, that wouldn't give it any advantage over all the elephants with brown eyes, so the genes for blue eyes would likely disappear from the population after a few generations because there would be no selective pressures leading to this gene spreading faster in the population than the brown eye gene.
So, animal species with different eye colors have evolved those eye colors because they provide some sort of advantage, or because other eye colors would provide no distinct advantage to them. Animals with red eyes, such as the satanic leaf-tailed gecko and the black-crowned night heron, are able to distinguish more easily between colors, and filters out UV light. Black eyes help protect the eyes from damage from UV for diurnal animals, and absorbs extra light to help with night vision in nocturnal animals.
However, domesticated animals may also display different eye colors from eachother. Most cats have yellow eyes, which is their ancestral condition, inherited from the first wild cats to be domesticated. But a breed called the Russian Blue is distinguished for having green eyes, and Siamese cats have blue eyes. This is simply because of artificial selection. Breeders of the past had a kitten born with a different eye color, and then specifically bred that individual and its unusually-colored eyes offspring more to propagate that trait more in the population simply because it's pretty. There are other examples of this too. In ball pythons in the pet trade, individuals with blue eyes can be incredibly expensive because it's a rare trait that many people adore.
But it's also important to note that how human eye colors are determined are very different to how other animals' eye colors are determined. It's been a long time since I took genetics courses so I may be misremembering some things, but if you breed a cat with yellow eyes with a cat with green eyes, when it comes to the genes for eye color, the offspring will all get one gene for yellow eyes from the yellow eyed parent, we'll call that Y, and a gene for green eyes from the green eyed parent, we'll call that g. So each kitten will have a gene pair Yg for eye color. Because Y is dominant over g, all these kittens will have yellow eyes, because a dominant gene has priority for being expressed over a recessive gene. But if, down the line, two descendants of this pairing mate and both have Yg genes, then 25% of their kittens will have YY genes, 50% will have Yg, and 25% will have gg. Because there is no Y presiding in a gg pairing, those offspring will have green eyes.
In humans, if I remember correctly, there are two pairs of genes that primarily affect eye color (though there are others that can influence it as well). There's a pair that consists of an A and an a as possibilities, and a pair that consists of B and b. Each pair has three possible outcomes: the A pair can result in offspring with AA, Aa, or aa genes, while the B pair has outcomes BB, Bb, or bb. It's the combination of the results of both of these genes together that produces the offspring's eye color. For example, someone with aa bb genes will be born with blue eyes, someone with Aa bb will have green eyes, and people with Aa Bb, Aa BB, and AA BB will have various shades of brown eyes. As far as I'm aware, no other animal has eye colors determined in this way (though there are other factors regulated like this, just not eye color). As to why it's this way in humans only, it's likely because this mutation happened to occur in a species that thinks that different eye colors are attractive, and that aided this system of eye color determination to spread throughout our species. -
R relay@relay.mycrowd.ca shared this topic
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@mir actually, humans are relatively unique in the way our eye colors are handled. There are up to 16 different genes currently identified in humans that control various factors relating to eye color, and so eye color is determined largely by your parents' eye colors, creating a variety of different eye colors within the total human population.
In wild animals, eye color is typically consistent within a species. All elephants have brown eyes, for example. The reason for this seems to be because there's no evolutionary advantage to eyes of a different color. If an elephant was born in the wild with blue eyes, for example, that wouldn't give it any advantage over all the elephants with brown eyes, so the genes for blue eyes would likely disappear from the population after a few generations because there would be no selective pressures leading to this gene spreading faster in the population than the brown eye gene.
So, animal species with different eye colors have evolved those eye colors because they provide some sort of advantage, or because other eye colors would provide no distinct advantage to them. Animals with red eyes, such as the satanic leaf-tailed gecko and the black-crowned night heron, are able to distinguish more easily between colors, and filters out UV light. Black eyes help protect the eyes from damage from UV for diurnal animals, and absorbs extra light to help with night vision in nocturnal animals.
However, domesticated animals may also display different eye colors from eachother. Most cats have yellow eyes, which is their ancestral condition, inherited from the first wild cats to be domesticated. But a breed called the Russian Blue is distinguished for having green eyes, and Siamese cats have blue eyes. This is simply because of artificial selection. Breeders of the past had a kitten born with a different eye color, and then specifically bred that individual and its unusually-colored eyes offspring more to propagate that trait more in the population simply because it's pretty. There are other examples of this too. In ball pythons in the pet trade, individuals with blue eyes can be incredibly expensive because it's a rare trait that many people adore.
But it's also important to note that how human eye colors are determined are very different to how other animals' eye colors are determined. It's been a long time since I took genetics courses so I may be misremembering some things, but if you breed a cat with yellow eyes with a cat with green eyes, when it comes to the genes for eye color, the offspring will all get one gene for yellow eyes from the yellow eyed parent, we'll call that Y, and a gene for green eyes from the green eyed parent, we'll call that g. So each kitten will have a gene pair Yg for eye color. Because Y is dominant over g, all these kittens will have yellow eyes, because a dominant gene has priority for being expressed over a recessive gene. But if, down the line, two descendants of this pairing mate and both have Yg genes, then 25% of their kittens will have YY genes, 50% will have Yg, and 25% will have gg. Because there is no Y presiding in a gg pairing, those offspring will have green eyes.
In humans, if I remember correctly, there are two pairs of genes that primarily affect eye color (though there are others that can influence it as well). There's a pair that consists of an A and an a as possibilities, and a pair that consists of B and b. Each pair has three possible outcomes: the A pair can result in offspring with AA, Aa, or aa genes, while the B pair has outcomes BB, Bb, or bb. It's the combination of the results of both of these genes together that produces the offspring's eye color. For example, someone with aa bb genes will be born with blue eyes, someone with Aa bb will have green eyes, and people with Aa Bb, Aa BB, and AA BB will have various shades of brown eyes. As far as I'm aware, no other animal has eye colors determined in this way (though there are other factors regulated like this, just not eye color). As to why it's this way in humans only, it's likely because this mutation happened to occur in a species that thinks that different eye colors are attractive, and that aided this system of eye color determination to spread throughout our species.@ActuallyAubrey@void.lgbt i love that there is something called the "satanic leaf-tailed gecko" lol
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@ActuallyAubrey@void.lgbt i love that there is something called the "satanic leaf-tailed gecko" lol
@mir definitely one of the coolest creature names out there!!
