Lutino
Sex-linked Mutation
The Lutino Cockatiel mutation is sex-linked recessive and is one that seems to stand out from the crowd. It’s bright yellow colour devoid of all dark contrast except for the orange cheekpatch make them a striking looking bird. Also the presence of the red eye instead of the normal dark colour give it a unique look. Lutino can be combined readily with the pearl, pied, cinnamon and whiteface mutations to further enhance the beauty of this colour. Lutino Cockatiels are a colour that makes visual sexing of the bird very difficult and the subtle differences between the sexes can often be nigh on impossible to distinguish.
One negative trait of lutino cockatiels has been a bald patch which is apparent behind the crest area on the head. Fortunately with successful selective breeding practices this trait is being reduced. There are some magnificent specimens around now that have total feather coverage of the head.
The lutino gene is called a sex-linked recessive gene. It is one that affects the grey family of pigments in birds and is one of the easiest to recognise. Basically this gene successfully prevents the production of grey colours or ‘melanin’. So if you imagine a normal grey cockatiel that has all the grey washed out or taken away then you will see a lutino.
The lutino gene in birds is the equivalent of the Albino gene in mammals. In mammals this gene leaves a white creature with red eyes because the melanin has been removed. In the lutino the same effect has taken place. The reason we don’t get a white bird from the lutino gene is because birds do not just have one form of pigment, ie melanin, as mammals do. Birds have grey family pigments (melanin) and yellow family pigments (psittacins). To get a white bird both these pigments need to be removed and there is no one gene that is capable of doing that. Having said this though it is possible to get a white bird by the combining of the lutino gene that removes the melanin and the blue or whiteface gene that removes the yellow. Thus the albino cockatiel is genetically a Whiteface Lutino.
Now we get down to the technical part of inheritance, or how a bird can be a lutino cockatiel and what does it need from what parent. This is where the term sex-linked recessive needs to be explained.
As most people know in humans, each person basically contains pairs of chromosomes that hold all the information that make us what we look like. To determine the sex of a human child each baby has a pair of chromosomes that are either XX (female) or XY (male). In birds this is the opposite way around so it is the female that has the XY combination and thus it is her that determines what sex each chick will be. So basically it gets down to the point that the cock bird carries two ‘X’ chromosomes while the hen has only one.
The lutino gene is one that is carried on the sex chromosome or X. The Y that the hen contains as her second one is too short to carry any wild-type genes that would suppress or oppose those carried on the X. Thus if the X chromosome contains the lutino gene in a hen, she will be a visual lutino bird because she has no gene on her Y chromosome to dominate over the lutino. In a cock bird though because he has two ‘X’ chromosomes if he has only a lutino gene on one of them then he will have a wild-type or normal gene on the other that would prohibit the lutino from being visible. If he had a lutino gene on both X’s then there is nothing to prohibit it from being visible and the bird would thus be lutino. I hope I still have you with me at this point!
So when we have two birds making babies each parent will give either one of their two sex chromosomes to a chick. The male has only two ‘X’s so he will give one of them whereas the hen could give either an X or a Y. Because the lutino gene is carried on the X, any chick from a visual lutino father will get a lutino gene. With the hen having an X and a Y she could pass on either but remember only the X holds the lutino. So if she passes the X to a chick it will have an X from mum and an X from dad and so will be an XX and thus a boy. If the mother passes the Y gene the chick will have an X from dad and the Y from mum and be a girl.
From this we should see that only a chick that gets an X chromosome from mum can inherit any sex-linked genes from her as the Y contains none. So it is impossible for a hen to pass any of these on to any female chick she produces.
So we have a scenario where we have a lutino hen and a normal grey male. Dad will give each chick a normal gene and mum will give her sons the X that contains the lutino gene and her daughters the Y that contain no genes. Thus each male chick will have a normal gene and a lutino gene. The lutino is opposed by the normal and thus called recessive and will not show up visually. He will be then termed ‘split lutino’. He can then give any of his chicks either a lutino or a normal and if he gives the lutino to a daughter then she will be visual lutino.
I hope this makes sense. If you have any questions please feel free to email me and I will help wherever I can.
All of these chicks below I know are definitely hens because mum was not a Lutino and dad was only split Lutino.
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