If any of the information on here is incorrect or inaccurate please let me know! I am not an expert on the subject of genetics so mistakes may and probably have been made!!! EDIT 5/7/2013 Removed from TBT. I thought it would be nice to help people learn some stuff about feline genetics but apparently I was wrong. This is just for basic cat genetics from now on.
-NOTE: Albinos actually only have a red pupil. The rest of the eye is a lavender-y colour due to a film of blue that lies over the un-pigmented pink eye- A big thanks to =meeshapom for letting me know about this!
NOTE: Purple eyes are possible in cats but seem to occur only in pointed breeds. They are, however, rarer than a calico male so keep that in mind!
Blue eyes do not just occur on a cat with a lot of white. The loss of pigment must cover or surround the eye. This is because blue eyes are created from a loss of eumelanin, and the white "erases" the pigment in that area. This is the same with dogs and horses.
Also, even though it does say that ALL calicos and torties are female and there is a small chance that males can have this pattern, but I would like you to know something. There has been at least 4 known cases of male calicos/torites. This is caused by Klinefelter's Syndrome. This creates a sterile male in cats and males them calico/tortie. The reason being is because the calico and tortie gene is a sex-linked trait and is shown like this XOXo. O being orange and o being black, giving it the orange and black spotting. The only way that a male is calico/tortie is if he has two X chromosomes instead of and X and a Y. So, when the male has Klinefelter's Syndrome, he has two X chromosomes and one Y chromosome, which is a true effect of this disease. Humans can also get this, but there are other effects. So, the male calico's/torties' genotype would be: XOXoY
This is very helpful though, and thanks for sharing!
I'm actually working on an updated version of this guide so some of the information on here isn't exactly 100% accurate!
See, I had a feeling that the white had to be around the eye area for it to be blue but other sources stated that as long as the cat had the dominant white gene and displayed some white that it was capable of having blue eyes, albeit a very rare occurrence, but I will certainly have to look into that further. There's also the ojos azules cats and pointed cats but those are exceptions to the rule I guess.
Thank you for explaining how the dominant white causes blue eyes, I had assumed that it caused loss of some sort of pigment but I didn't know the specifics of it!
Haha my knowledge of torties was very limited at the time although I do believe I mentioned that males were possible. During my first year at college I actually had a section in my genetics class on how tortoisehells occured and that is hopefully going to be the subject of my first new guide! From what I've read there seem to be three main causes of male tortie cases: klinefelter's syndrome (as you mentioned the XXY), chimerism, and in some cases the male torties were actually females with enlarged clitorises, similar to that of a female hyena and were mistaken identity.
I'm just curious, do you know how the male tortie gene is passed on? I know that sterile torties are a rarity but there have been some documeted cases where a male tortie bred to a tabby female produced male tortoiseshell offspring. From the other cases I've read the XXY seems to have X-inactivation and only one X chromosome can be passed on to the female offspring (or else you'd have an XXX!) but does this mean that instead of passing on the Y they pass on an XY instead? Is that even possible? I could see it happen if it where an XX being passed on but it just seems strange to have the X and Y passed on together.
Regardless I am glad to see someone as interested in feline genetics! Thank you for sharing your knowledge too! Hopefully my new guides are more up to date on their info but as with all genetics new discoveries pop up all the time!
Yes, pointed cats such as Siamese and Burmese are an exception to the rule on having blue eyes.
For the male tortie gene to be passed on, the male must not be sterile, but he is.
Also, another way for the Klinefelter's Syndrome to pass one, a rare mutation must take place. When the chromosomes are exchanging data to create the offspring, something may occur. Parts of the chromosome sticks on and doesn't let go, giving you an extra gene in that trait. The same goes for the sex chromosomes. For some reason, two X chromosomes go at one time, most likely one from the mother and one from the father, but the Y chromosome goes along with the father's X chromosome, creating the XXY genotype! Also, what you have stated is true. But, sometimes both of the X chromosomes are active, creating a sterile male tortie. If the other X chromosome is dormant, the male is usually sterile since it can both reproduction organs, such as hermaphrodites, which are also sterile. Also, the XXX genotype can happen, but the only cases I've heard of are in humans. This is known as the Trisomy X disease, or the "Super Female" syndrome and causes mental retardation. I am also really not sure how the passing on of genes works when it does come to the crossing of a Klinefelter's Syndrome cat to a normal cat would work. If one of the X chromosome is dormant, it may just ignore it and just pass on the genes norma. Or you could end up with another Klinefelters cat and a "super female" cat. But this is also probably why more of the cats with klinefelter's Syndrome are sterile.
And your welcome. I have been fascinated in animal genetics for a while and have been studying on it a lot! I am studying dog, cat, and horse genetics at the moment, but I am soon (hopefully) getting into a rabbit breeding business and will be learning about rabbit genes as well! Also, if you ever need help with anything, I can always help! I am learning more everyday and can help with almost anything (other than newer discoveries).
It is true that black cats can have blue eyes but it is such a rare occurrence that I decided not to include it on the guide! I did, however, mention that cats of any colour with a lot of white can have blue eyes! www.cat-world.com.au/General-C… The above link lists the main reasons that blue eyes occur in cats and it's pretty interesting how few breeds there are that can have blue eyes. From what I've heard it seems like most solid black cats with blue eyes have some siamese ancestry which causes the blue colour. Although, I'll admit I've never heard of the breed Ojos Azules, but they are some gorgeous cats indeed!
I'm glad you liked the guide! It was super fun to research and I've definitely learned a lot from it <33
This is so handy! I try to be mostly genetically accurate with my characters but sometimes it's just a hassle to go through huge websites (like Messybeast) just to find the things I want. Thanks so much! Why did TBT kick it out? It's so useful.
I actually removed it myself from the group after I went on a livestream and saw a few people complaining because it 'took away their creativity.' I can sort of see where they are coming from but this was made to be more of a guide than a strict rulebook list. It's purpose was and still is to inform people about feline genetics and, if they so wish, they can then apply that to their cats to be somewhat more realistic. I personally don't care if people have sparkle cats and ginger tabbies with purple eyes as long as they love their character but I know that many people have old me how helpful this was and that they didn't know a lot of the facts on here!
I think there's two sides to it - on one hand, letting all your creative juices flow produces some stunning characters, even if they couldn't ever occur naturally. On the other, there's something to admire about making the best with what is realistic and still coming out with a kickass design. I kind of straddle the line myself with my more recent sketches (that I haven't posted yet sigh) That being said, knowing cat color genetics, eye color restrictions irl, and types of markings literally cannot hurt. I totally agree with the part about loving their characters' designs. If they want to use it, then that's their choice; if they don't, they can love their characters just the same without it. There's nothing wrong with questioning a design and deciding to keep it the same.
I agree I've seen some stunning designs that don't always adhere to real life. And I know how tempting it can be to add blue eyes to a cat that would never have blue eyes in real life too!
I think it's more of a personal preference. I love cats with realistic designs <33 There are so many possibilities out there! Most often I see cats with an eye colour that isn't possible or something like a white tabby or a solid orange cat. One of the things that bothers me the most is the male calico/tortoishell. I know that they are gorgeous but in reality they are hardly ever male and even if they were here is a 99% chance that they would be riddled with health problems. I believe Redtail and Sol from the original books are largely to blame for this though.
btw I think all of your designs are stunning *w* I can't wait to see the ones you upload!
I admit to doing the blue eyes on a grey cat siiiIIIIGH but i'm so used to it that I can't possibly change it now xwx I've been trying to figure out a way to make it work and the closest I came was ocular albinism, but I'm not actually sure if cats can HAVE that. I know people can though. What gets to me the most is "silver tabbies" that are actually light blue or lilac/lavender tabbies. Silver tabbies have black stripes and grey-white to pewter bodies and I guess it's just super-frustrating to me for some reason x-x Oh gosh thank you!! I'm mostly trying to refine the colors to make them flow better/more like an animation-style thing and fix up the design of Sageheart. She is a real problem considering she's based on me uuuuugh