Brief Cockatiel Genetics
I'm Still Learning!

Dominant Colors:

     Normal Gray
     Silver
     Yellow Cheek

Recessive Colors:

     Pied
     Whiteface
     Fallow
     Pastel
     Emerald (Spangle)
     Silver

Sex-Linked:

     Lutino
     Cinnamon
     Pearl
     Yellow Cheek
     Platinum

Ok, genes come in pairs, one from the mald and one from the female.  Mutations can
affect both  genes, only one  or possibly neither!   These different  combinations
affect the birds color and hidden color splits and determines whether its color(s)
is/are dominant, recessive or sex-linked.

The dominant color only needs to be present in one copy of the gene.

A recessive color must affect both copies of the gene in order to change the birds
appearance.  A whiteface, since it is recessive, must have inherited a copy of the
whiteface gene from each of the parents.  If it only received one copy of the gene
then it is called a split and since it  is only split, it will only pass this gene
onto 1/2 of its offspring.  In this case it will be a "hidden" color that will not
be  seen.  Most splits  are not  visual but the  most commont  visual split is the
"pied" mark, usually a patch  of white or yellow feathers  behind the head or dark
and white toe nails.

Sex-linked colors are only carried on one of the sex chromosomes. Females can only
have one copy of a sex-linked mutation.   Because of this, females cannot be split
to a sex-linked  mutation.  Hence, if the female does not carry  the visual color,
she doesn't carry it at all.

Males  inherit one chromosome (X1) from  the father and one from the mother  (X2).
Both of  these chromosomes can carry a  sex-linked mutation.  In the  babies, they
will get both the chromosomes from the father and the mother.

Pastelface is sometimes called dominant  but it is recessive to normal gray.  But,
in  relationship to  the whiteface it  is dominant.  The two  mutations affect the
same gene.