Hi everybody ,

This topic was put in the arab version of the forum by " Dr. Hassan Salama " so all his copyrights are reserved . I chose the cockatiel related part of that topic .

This is the link of the original text : http://www.canaryfans.com/forum/viewtopic.php?t=14617" onclick="window.open(this.href);return false;

As I previously mentioned : Cockatiels are like all other creatures . Their characteristics and colors are determined by a kind of nucleic acid called DNA ( Deoxyribonucleic acid ) which is formed by a group of genes that determine the shape , color and structure . These genes are carried in each cell by chromosomes . Every living-organism has a number of these chromosomes that carries his genes which determines his characteristics .

These chromosomes are classified into two categories :

1 - Autosomal chromosomes : ( carry color , shape and size genes . )

2 - Sex-linked chromosomes : ( determine the gender of the bird , some color and pathological traits . And this is our main topic .)

Sex-linked chromosomes are a pair of chromosomes one called " X " and the other is " Y " . Hereditary traits are carried only on the " X " chromosome and is never carried on " Y " chromosomes . Most sex-linked genes are recessive and don't appear unless they are clear .

In humans the male determines the sex as he has two chromosomes one is called " X " and the other is called " Y " and the traits are carried only on the gene of " X " . Females have " XX " chromosomes and males have " XY " chromosomes . Then if the male has a trait on the gene of " X " chromosomes it appears . But females have two genes the one which determine the trait is the dominant gene .

Birds are opposite to humans . Which means that the one which determines the sex is the female as it has the chromosomes " XY " , but the male has the similar chromosomes " XX " . So any color trait carried by the female must appear , but a male can carry a trait on one of the two " X "s without appearing . Males can be " Split " as they have 2 Xs and one might be dominant and the other recessive .

Now I'm going to give an example of a sex-linked trait and let it be Cinnamon :

- Cinnamon cock structure : Xc Xc
- Split Cinnamon cock structure : Xc Xn
- Normal cock structure : Xn Xn
- Cinnamon hen structure : Xc Y
- Normal hen structure : Xn Y

- When pairing a Cinnamon cock with a Normal hen : ( knowing gender from the nest ) :

Xc Xc with Xn Y =
Xc Xn + Xc Y
Xc Xn + Xc Y
All cocks will be Normal split to Cinnamon .

- When pairing Normal cock with Cinnamon hen :

Xn Xn with Xc Y =
Xn Xc + Xn Y
Xn Xc + Xn Y
All cocks will be Cinnamon split to normal .

- When pairing a Normal split to cinnamon cock with a Normal hen :

Xc Xn with Xn Y =
Xc Xn + Xc Y
Xn Xn + Xn Y
50 % of cocks will be Normal
50 % of cocks will be Normal split to Cinnamon
50 % of hens will be Normal
50 % of hens will be Cinnamon

- When pairing a Normal split to cinnamon cock with a Cinnamon hen :

Xc Xn with Xc Y =
Xc Xc + Xc Y
Xn Xc + Xn Y
50 % of cocks will be Cinnamon
50 % of cocks will be Cinnamon split to Normal
50 % of hens will be Normal
50 % of hens will be Cinnamon

Sex-linked mutations :

1- Lutino : ( recessive sex-linked trait ) :

This gene hides the melanin pigment and keeps the lipochrome pigment which gives the feather the yellow or cream white color as well as tail and wings barrings. The psittacins pigment occurs to give the cheek patches their orange color . The lack of melanin pigment in the cells of the body causes the red color of eyes and pink color of legs . Baldness occurring behind the crest, as an inherited trait and increases by inbreeding .

2- Pearl : ( recessive sex-linked trait ) :

All feathers are spotted with the lipochrome pigment or no pigments which shows a white color on the grey , brown or yellow background . Males lose these pearl lacings by the first molt and continue to lose them on each molt . Females keep these pearl lacings without being lost .

3- Cinnamon : (recessive sex-linked trait ) :

A more pronounced brown shade lacking any grey overtones, is preferred. Some hens may have more yellow (lipochrome pigment) on the face than their normal grey counterparts.

4- Platinum :

Has less melanin pigment , which makes the bird yellow washed with light grey color . Male birds might carry the Lutino gene on X and the Platinum gene on the other X , and is called " Platino " ( Platinum + Lutino ) , this doesn't appear on females of course .

5- Yellow-cheek ( sex-linked ) :

The psittacins pigment doesn't exist , so the cheek patches turn peach-yellow or blend in the yellow male face and washed in females dark face .

6- Albino :

In cockatiels Albino gene doesn't exist , but in fact it's a combination of two color traits one of them is Lutino where melanin pigment disappears and the other is recessive White-face where lipochrome and psittacins pigments disappear . So all feathers appear white , pink legs and red eyes . Actually it's deprived from all pigments and doesn't have a recessive Albino gene .

Best wishes and Good luck

Thanx,

You are great.

Hi Abdo Abu Seir ,

Thank you very much for giving us this amazing opportunity , it very beneficial