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| Genetics, Mutations, and Names of Gouldians:
There are pictures of these mutations with notes under bird photos.
Simplified Genetics...
I know when I first started to keep and breed gouldians I found this topic most confusing. I really didn't comprehend much of it until I studied the book The Gouldian Finch by Authors: Stewart Evans, Mike Fidler, Dr Stacy Gelis, Russell Kingston, Dr Debra McDonald, David Myers and Sarah Pryke
Also the book A Guide to Gouldian Finches
and their Mutations by Authors: Milton Lewis, Dr. Rob Marshall, Dr. Terry Martin, and Ron Tristram
I highly recommend both. I will now give you my simplified version of gouldian genetic and the resulting mutations.
Let's talk color....
There are 2 type of colors in play. The Pigment color and the Structural color or Optical properties that we see.
Structual color: The way light reflects determines what colors we see. Example: The blue on the neck and rump of the gouldian is not the actual pigment color. It is the results of the barbs on the feathers. This structure is called boxed celled. They absorb light from the red spectrum and reflect it as blue spectrum...cool hunh? we see blue though there is no pigment for blue found in the pigments of gouldians.
Another cool note... gouldians can see reflected light in the ultraviolet range...we cannot as we have only human eyes. So they may see each other very different than we see them.
Pigment color: There are 4 pigment colors. 2 are known as Melanins and 2 are known as Carotenoids.
Melanins: 1) eumelanin = black
2) phaeomelanin = reddish-brown
Carotenoids: 1) lutein = yellow (absorbed through food)
2) astaxanthin = red (made by the body with lutein)
The different parts of the bird or under different color influences. The blues are a result from the structural properties.
Single pigments are the result of the yellow color of the belly and the head colors. However the black headed bird has distinctly different feather barbs than the red or yellow headed bird. The black head's feathers are much finer where as the red and yellow heads have fattened barbs. The single pigments listed above are the ones responsible for black, red, and yellow heads.
Now for the rest of the bird, the purple breast, the dark blue in the tail, the green of the back. These occur by pigments mixing or ommiting, thus producing a new color. Yellow pigment with blue structural color makes green. phaeomelanin, or reddish-brown, mixed with blue structual creates Purple. Eumelanin, or black, added to structual blue creates the dark blue of the tail feathers. Not so complex after all, Males have more pigment than females, hence the depth of their color.
Now for the mutations of things such as white breast, blue back, and lutino. These mutations have been observed in the wild. Though they are not likely to reproduce. Shunned by the group due to their odd color, target for easy prey, or simply do breed yet the trait is a recessive gene and it would take 2 birds that carried it to visually show it. Odds are low for that happeneing.
Mutations are simply the failure for the bird to produce normal color pigments.
Example: A bird failing to produce the structual blue feathers then the result would be a lutein pigmented bird only...thus yellow.
A bird not able to manufacture lutein from their food would result in a blue bird since lutein is responsible for the yellow (yellow + blue=green in normal wild colored birds) They also lack the red coloration as the astaxanthin is made from the lutein.
A white breasted bird lacks the ability to produce any color. A genetic defect from the wild bird. White breast is a recessive trait.
A lilac breasted bird is only partially blocked and is also a recessive trait.
Mutations can happen at any time. It is simply a result of a genetic defect. Though most mutations today are bred from generation to generation from the first carefully bred mutants.
Never quite looked at it like that, now did you?
Let's Talk Genes...
Foundation of genetics:
Life starts as a single cell which divides into 2 cells, then four cells, then 8 cells, then 16 cells... okay you get the idea.The instruction of the cell is contained in the nucleous. The nucleous contains the chromosomes which are always in pairs. There are 2 kinds of chromosomes.
1) autosomal chromosomes- these are similar to one another,in length and shape. These are known as X chromosomes. All are of this kind except for one pair.
2) sex chromosomes - A stunted , vestigial structure and different from the X chromosomes. This sex chromosome is know as the Y chromosome.
Females have only one sex hormone therefore is know as XY. Males have 2 x chromosomes , known as XX.
Y chromosome carries no genetic material but the X chromosome carries the full genetic material.
So how do these chromosomes make beautiful colored birds?
They form a special DNA code. This code is a specific set of instructions to the developing chick. These instructions are inherited from the parents. One set from the cock and one set from the hen. Sex and color are inherited traits.
Dominant and Recessive Traits:
If one genetic trait takes precedence over others it is called dominant.
Such as, red head feathers are dominant over black head feathers. So if you have a red head father and a black head mother then all the chicks will have red heads like there father. However the chicks will have also inherited aone gene from their mother, the black head, which is recessive. So even though theses chicks look like they are red headed, they have a hidden black head gene. This is what is referred to as split for. Meaning that it is a red head split for black head. Written like this: RH/BH. So if that chick is later paired with a black head or split to black head mate then they could produce black headed gouldians. They will also produce the dominant red head.
The term for birds that are pure color (no splits) is called homozygous.
The birds that have a hidden recessive trait or 'split for' are called heterozygous. These are the genotype of the bird.
When a trait can be passed down from either parent it is called and autosomal genotype. However some traits are sex linked..............
Sex Linked Traits:
When an egg is fertilized by the male's sperm and the hen's ovum it receives a combination of the parents genes, traits, or chromosomes. Both sets of chromosomes provide genetic instructions gor the chick. These instructions are passed on like in the earlier color iherotance discussed earlier with the exception of the chromosome that control sex-linked traits.
As pointed out in the beginning the hen sex chromosome is shorter than the cocks. This means that it will only contribute one gene for each trait that is on that part of the chromosome.
Red Head and black head are sex linked traits. This means that recessive traits passed on by the father can be espressed just as easily as dominant traits if the hen does not have a complimentary dominant gene on her chromosome...... This part still confuses me,,,,,,,
A simlper way to say it is a male chick will always show the dominant color, no matter which oarent it got it from. Female chicks receive a shorter chromosome so this means that they only need one recessive gene from their father to display the recesive color.
For example...If you have a single factor pastel male (dilute) and a green hen breeding.. you could get yellow hens because they could get the one recessive yellow gene from the father. Boy was I surprised to get a yellow bird from my green parents the first time this happened. As a matter of fact this is what made me dwelve into studying genetics...inquiring minds want to know.
Now more confusing stuff. The yellow headed bird, which many people call orange head because it does look orange. The yellow head gene surpresses the carotenoid synthesis which produces the red color. ( red color is produced in the body by lutein..go to the color section and read again) This can be passed by either parent, and autosomal trait. The lack of red pigment that produces this yellow or orange head can only be seen if the bird was a red headed bird to begin with. The way these traits mingle it means that a yellow headed hen will always be homozygous (can not be split for another color). A yellow headed male can be yellow or even split to black. How do you know if the bird has the yellow gene? Look at the beak. If the yellow headed bird is showing in a visually black headed bird then the beak will be tipped in yellow. But also, a black headed bird can carry the yellow trait without expressing it. This will show as a black headed bird with a red tipped beak.
The way you pair a sex linked trait will have a great effect on the color of the chicks. Many times you will not get the recessive color with the first generation (F1). But will only get split birds. With the next generation greater possibilities develope. For example. If you have a normal, wild type green backed bird and you breed it with a blue hen you will not see any blue chicks in the nest. But each one of those chicks will have the recessive trait hidden within them. These will be called split to blue. When these chicks are bred with other split to blues or blues you will then get blue chicks in the nest. Boy was I surprized the first time I had a blue chick in the nest of 2 normal looking green backed birds.... I had bought them as greens and they turned out to both be split to blue. Back to the genetic studies I went. The thing about split birds is that you just can't tell by looking at then if they are or not. Buying from a breeder who keeps accurate records helps out a lot. But then again, if you are like me, surprizes are fine too.
Another point to make on this example...say you have a green looking male bird that is split to blue and you bred it to a green looking hen that is also split to blue.. you may get blue chicks, green chicks split to blue, or just normal green chicks. The catcher is you will not know which of the green chicks are normals and which ones are split to blues....that is until you breed them. If you get blue chicks in the nest then they are split. But don't be dissapointed if you don't get blues the first clutch...this does not men that they are necessarily normals. I had a pair of 'normal' greenbacks that bred the first year. They had 3 clutches of pretty green chicks. The next year again I paired them and got 2 clutches of green chicks and then on the 3rd cluth there was a blue, actually 3 blues. They produce at least 20 chicks before the recessive gene matched up and produced a blue. I will pair them together again next year.
It's kind of like Forest Gump says.."It's kind of like a box of chocolates... you never know what you are going to get." At least in the case of buying a bird that the parentage is not known.
Here is a link to n online gouldian gnetic mutation forcator. You don't have to download anything. Just type in the color of your male and the clor of your hen and it will calculate the possible outcome of the offsprings and the percentage that these colors will occur. You can learn a lot by just creating different dream pairs.
http://www.amadinagouldove.cz/gouldian-genetics-forecast-online/english/
Another excellent , more advanced forcastor, also for other species
http://www.finchbreederdatabase.com/phpBB3/birds_manual.php?mode=genfor&species_id=29
The above forcastor link is from the finch breeder data base and is one of the most comprehensive record keeping site out there. It is free and the owner is constantly striving to update all aspects of finch ownership. There is much info on species and the basic facts of that species. Also a forum where you can ask questions and share information with other finchers from around the world. I urge you to check out this great site.
http://www.finchbreederdatabase.com/phpBB3/birds_manual.php |
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