[WARNING- genetic geekery ahead!]
Let me just say this- fox color genetics in Planet Zoo are whack. But I think- after breeding over 5000 foxes and keeping good records on the last 2000 or so- that I may have them figured out. I’d be thrilled if a developer jumps in to confirm or deny!
The color genetics of red foxes in the game are decidedly not simple Mendelian, nor do they follow the same rules as real fox genetics. Here’s the best take I have on how they work.
Let’s call the normal-colored fox “wild type”, or W. When each color morph was created by Frontier, it was given individuals who are homozygous for- have two copies of- the color gene for that morph. So, for example, we could say a cross fox had CC, a black fox had BB, etc. And, among each color morph, its color is dominant. So, for example, if you breed two black foxes, B is dominant; if you breed two cross foxes, C is dominant. That means that each color normally pretty much breeds true. (Frontier likes to throw in a “throwback” wild-type animal every 100 births or so; those can be disregarded.) It also means that a pure-breeding strain of color morphs could “hide” genes for other colors that are recessive to the morph color.
So what happens when you breed two color morphs together? It appears that whichever pair of genes that the animal gets that is highest on the color scale determines the color of that animal. And it also appears that the order of dominance, from most to least, is:
Leucistic (L)
Black (B)
Cross (C)
Silver (S)
So, if an animal happens to receive two pairs of color genes, the most dominant will be its phenotype. So, for example, it would be possible to have an animal with genotype LLBBCCSS. That animal would appear leucistic.
And, if an animal doesn’t get any matching pair of color genes, it will be W, or wild-type. Let’s indicate the absence of a gene with x.
So, for example, if I cross a purebred leucistic fox that carries no other color genes with a black fox that carries L but no other color genes, my offspring should be approximately half leucistic (genotype LLBx) and half wild-type (genotype LxBx.) None of the offspring should be black.
As a couple examples from my breedings:
Gwyneth, a purebred leucistic fox established through test breedings to carry no other colors(LLxx), was bred to Harry, a black fox carrying no other colors (BBxx.) Their 2 litters produced 10 pups, all wild-type, as expected. (LxBx.) A male from this litter mated to a purebred black fox carrying no other colors (BBxx) produced all black offspring (but could have produced wild-type as well.) A female from this litter mated to a purebred leucistic fox produced 2 wild-type and 4 leucistic cubs.
Keturah, a silver fox , was mated to Tegid, a test-bred pure leucistic fox. Their offspring were 4 wild-type and 1 leucistic. That meant that Keturah caries the L gene. Her genotype is SSLx.
Does this all make sense now? I told you it was whack. But this explanation seems to be working.
Let me just say this- fox color genetics in Planet Zoo are whack. But I think- after breeding over 5000 foxes and keeping good records on the last 2000 or so- that I may have them figured out. I’d be thrilled if a developer jumps in to confirm or deny!
The color genetics of red foxes in the game are decidedly not simple Mendelian, nor do they follow the same rules as real fox genetics. Here’s the best take I have on how they work.
Let’s call the normal-colored fox “wild type”, or W. When each color morph was created by Frontier, it was given individuals who are homozygous for- have two copies of- the color gene for that morph. So, for example, we could say a cross fox had CC, a black fox had BB, etc. And, among each color morph, its color is dominant. So, for example, if you breed two black foxes, B is dominant; if you breed two cross foxes, C is dominant. That means that each color normally pretty much breeds true. (Frontier likes to throw in a “throwback” wild-type animal every 100 births or so; those can be disregarded.) It also means that a pure-breeding strain of color morphs could “hide” genes for other colors that are recessive to the morph color.
So what happens when you breed two color morphs together? It appears that whichever pair of genes that the animal gets that is highest on the color scale determines the color of that animal. And it also appears that the order of dominance, from most to least, is:
Leucistic (L)
Black (B)
Cross (C)
Silver (S)
So, if an animal happens to receive two pairs of color genes, the most dominant will be its phenotype. So, for example, it would be possible to have an animal with genotype LLBBCCSS. That animal would appear leucistic.
And, if an animal doesn’t get any matching pair of color genes, it will be W, or wild-type. Let’s indicate the absence of a gene with x.
So, for example, if I cross a purebred leucistic fox that carries no other color genes with a black fox that carries L but no other color genes, my offspring should be approximately half leucistic (genotype LLBx) and half wild-type (genotype LxBx.) None of the offspring should be black.
As a couple examples from my breedings:
Gwyneth, a purebred leucistic fox established through test breedings to carry no other colors(LLxx), was bred to Harry, a black fox carrying no other colors (BBxx.) Their 2 litters produced 10 pups, all wild-type, as expected. (LxBx.) A male from this litter mated to a purebred black fox carrying no other colors (BBxx) produced all black offspring (but could have produced wild-type as well.) A female from this litter mated to a purebred leucistic fox produced 2 wild-type and 4 leucistic cubs.
Keturah, a silver fox , was mated to Tegid, a test-bred pure leucistic fox. Their offspring were 4 wild-type and 1 leucistic. That meant that Keturah caries the L gene. Her genotype is SSLx.
Does this all make sense now? I told you it was whack. But this explanation seems to be working.
