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02-12-2015, 12:58 PM
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#1
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Strong Brew Hamstery
Join Date: Feb 2014
Location: Ontario, Canada
Posts: 5,282
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Genetics behind odd-eyed Syrians
I'm looking for a bit more info on odd-eyed. I know it is generally seen with cinnamon and bands, and some in dominant spot. I have seen it also in blues and polywhites on rodent groups.
What exactly it happening? How does the combination of these genes cause odd-eyed hamsters? Is it independent from cinnamon/banded?
It's not in my line, and I've read it can't be bred for, but I'm interested in the general science behind it.
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02-12-2015, 01:45 PM
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#2
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Adult Hamster
Join Date: Aug 2013
Location: Waterford, Ireland
Posts: 293
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Re: Genetics behind odd-eyed Syrians
Hey Hekomi, I believe in mammals, bi-coloured eyes is in general a sign that the animal is a genetic chimera. Or in other cases in may never be obviously detected, as with some humans, until they need an organ transplant! Chimeras occur when the animal has at least two different sets of DNA. This is due to numerous fertilise eggs or zygotes fusing together to form the blastocyst which will develop into a foetus. There are loads of different ''types'' of chimera. The most obvious one and common one is where a two sperm cells are fused, but leave two heads, fertilising two eggs at the same time. So the resulting baby actually has 4 sets of DNA!
Oh, another aspect of chimerism is that some individuals may be hermaphroditic or in some cases sterile.
There is another similar genetic occurrence called a genetic mosaic or mosaicism. This is where an individual has two different populations of cells, of different genotype. These differing cell populations can occur in individual organs or cell lines.
But the main difference is: a mosaic animal forms from one single egg/sperm, with a mutation or other occurrence that prevents proper meiosis and mitosis. A chimera is formed from multiple fertilised eggs that fuse into one!
I think the mutation for the fur pattern calico is neither chimeraism or mosiacism, but a phenomenon called x-inactivation. A calico cat has two different x chromosomes, with each one expressed in a different somatic cells, in varying population numbers......but maybe this is just felines? I'm not too sure about hamsters?
I'm not too good on hamster genetics, so I just covered the basis of what is happening genetically in mammals.
Hope that explains it!
Ps. Oops, I forgot! Calico patterns and their family like tort and tri-colourations are all caused by x-inactivation.
Last edited by Hetty; 02-12-2015 at 02:58 PM.
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02-13-2015, 06:49 AM
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#3
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Strong Brew Hamstery
Join Date: Feb 2014
Location: Ontario, Canada
Posts: 5,282
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Re: Genetics behind odd-eyed Syrians
Interesting! I've heard some differing theories on how mosaic spots occur in hamsters, some being from chimeras, but others being from how the melanin responds within the body.
I hadn't heard of odd-eye being from genetic chimeras in hamsters! That would make sense. I had always heard it in relation to cinnamon and banding, and then no explanation beyond that. In my mind it's easy for it to make a mock fight scene between a cinnie gene and a band gene, in which the band gene goes "HAH!" wins, and makes one eye dark!
Chimeras are so fascinating. I haven't read much on them, but I was speaking with Moxie Hamstery about a "tort and white" coloured RCD in another country. I had seen one before, and knew it was a result of genetic chimera(ism?). This one was new - she was gorgeous, and I suppose she must have been XXX? as she had a litter. None turned out like her though. I'd have to find the page, it's somewhere on my facebook.
I cropped it myself, as the original (linked below) has images of very newborn pups.
https://fbcdn-sphotos-g-a.akamaihd.n...9b220cd86f8775
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02-13-2015, 09:31 AM
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#4
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Hamster Pup
Join Date: Apr 2012
Posts: 91
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Re: Genetics behind odd-eyed Syrians
I've never heard about odd-eyed being from chimera, and personally I don't think that is the case. No one knows for sure what causes it, but this discussion gives some interesting insights; https://groups.yahoo.com/neo/groups/hamstersinfocus/conversations/topics/2573 (from the Yahoo group "Hamsters in focus"). You may have to be logged in to read the thread. Make sure to read all 11 replys
I find the theories about there being a modifier or polygenic inheritance at play intriguing
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02-13-2015, 11:16 AM
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#5
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Strong Brew Hamstery
Join Date: Feb 2014
Location: Ontario, Canada
Posts: 5,282
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Re: Genetics behind odd-eyed Syrians
Cheers! I will take a look. I have seen Manuel around in a few areas. I'm happy to gather as many sources and ideas as possible! The more things I learn, the better.
Ah - I had read a bit from Janice too on it, in a facebook genetics group. I'm excited to read the other replies now!
"It may be a modifier that needs a white pattern and at least one cinnamon gene to express itself. There are rat breeders that specialize in odd eyes. Even they don't know the mechanism that's at work."
- Interesting!
The polygenic approach is fascinating too. I suppose we won't know for a while then.
Thank you for sharing that!
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02-13-2015, 11:49 AM
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#6
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Hamster Pup
Join Date: Apr 2012
Posts: 91
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Re: Genetics behind odd-eyed Syrians
You're welcome Some day hopefully we will get our answer!
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02-13-2015, 01:40 PM
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#7
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ST's Hamstery
Join Date: Dec 2013
Location: Mid Ohio USA
Posts: 2,574
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Re: Genetics behind odd-eyed Syrians
I have no idea how it is inherited, but I can say in my case it was two Dove Tort Band girls from two completely unrelated pedigrees, and one had the odd eye on the left , and the other had it on the right. One female above, Lesham proved unable to breed from an event in her past which left her terrified of any other hamster even near her bin so she was pet out. I will be breeding Darrah when she comes in heat to a Homozygous ED Black male who may carry for Cinnamon. The breeding is to test the male for Cinnamon and to add in his bloodlines to improve on his size. I'll let all know if I get any odd eyed offspring or not from this mating.
__________________
Nancy,and The ST's Hamsters
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02-13-2015, 02:14 PM
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#8
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Strong Brew Hamstery
Join Date: Feb 2014
Location: Ontario, Canada
Posts: 5,282
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Re: Genetics behind odd-eyed Syrians
Interesting! I can't wait to hear more Nancy.
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02-13-2015, 04:47 PM
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#9
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Adult Hamster
Join Date: Aug 2013
Location: Waterford, Ireland
Posts: 293
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Re: Genetics behind odd-eyed Syrians
Quote:
Originally Posted by Lemon66|
I've never heard about odd-eyed being from chimera, and personally I don't think that is the case. No one knows for sure what causes it, but this discussion gives some interesting insights; https://groups.yahoo.com/neo/groups/hamstersinfocus/conversations/topics/2573 (from the Yahoo group "Hamsters in focus"). You may have to be logged in to read the thread. Make sure to read all 11 replys
I find the theories about there being a modifier or polygenic inheritance at play intriguing
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Hi Hekomi,
I'm poor on Hamster genetics, most of the bi-eyed animals I have worked and seen are larger animals, not hamsters. The info I wrote on my first entry is just a brief intro about the basics of these genetic occurrences, for the majority of xx/xy mammals.
Bi-colourism of the eyes can be caused by x-inactivation (a type of modifying ''event''). This would be the far more likely cause of it, as oppose to chimerism ( an animal inheriting multiple genes, a poly -genetic event). X chromosome in-activation leads to animals exhibiting a tri-coloured coat. It can also be caused by genetic mosaic events, but this generally only leads to two colours showing.
Bi-coloured eyes can a multiple causes or sometimes be a spontaneous genetic mutation. But the fact that it is linked and seen mostly in animals with distinct coat patterns.
Sorry if I'm confusing you!
Those pictures of those hammies are divine, their coat patterns are pretty distinct!
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02-14-2015, 09:22 PM
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#10
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ST's Hamstery
Join Date: Dec 2013
Location: Mid Ohio USA
Posts: 2,574
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Re: Genetics behind odd-eyed Syrians
I Have had one Satin Heterozygous ED Black Dominant Spot girl who sadly was from a pet store surrender to me that had a BLACK eye and a Bright Red eye. Unfortunately she came here with being exposed to wet tail and she developed wet tail just a week of coming here, and sadly she failed to recover.
Here are the few Photos I got before she became ill. She was one beauty of a Hamster.
Flora:
Flora 3-30-14-c.JPG
Flora 3-30-14-h-Flora Flower.JPG
__________________
Nancy,and The ST's Hamsters
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