HAMILTON & DISTRICT BUDGERIGAR SOCIETY INC.



PRINCIPLES OF HEREDITY


We will now consider the means by which the mutations are inherited. This, in turn, determines what the offspring of various combinations will look like.
Dominant:
If one of the parent birds is purebred (see below) for the dominant color, all of the young will take on that color. In other words, the purebred dominant suppresses all other colors, even though the offspring carry other colors in their genetic material (or genes). Colors hidden in the genes can emerge later in particular pairings. In general, the wild color is dominant. (If two birds are purebred for the dominant color, all of the offspring also will be purebred for the dominant color.)
Recessive:
If two recessive-colored birds are bred, the offspring also will be of the recessive color. However, if a dominant bird is paired with a recessive bird, all the young will take on the color of the dominant bird. The recessive color is thus hidden.

-----------PARENTS--------------------------------------------YOUNG----------------------------------------
----MALE----------FEMALE-----------------MALES-------------------------FEMALES----------------------
Purebred (homozygous):
A purebred bird possesses only the genes for the revealed color. All recessive-colored birds must be purebred. Dominant-colored birds, however, may carry a masked gene of a recessive color.
Split (heterozygous):
This means a bird of the dominant color has a hidden color mutation, which can be passed on to its offspring. For example, a green bird with a hidden blue mutation in its genetic makeup is called "split for blue" or "green/blue."
Sex-linked:
This means that the inheritance of a particular Factor is dependent on sex. For example, hemophilia in humans is carried by females, hut is revealed only in males. It is thus important to know which parent has the appropriate colors that, with the sex, will be passed on to the young.
Sex-linked recessive:
This means that the recessive gene for a particular factor is associated with the group of genes (or chromosome) that determines the sex of the offspring.
Remember:

  1. In dominant heredity there are no split males or females.
  2. A sex-linked female can never be split for the color.
  3. In recessive birds, regardless of their gender, both male and female can be split.
Autosomal:
This refers to inheritance that is not sex-linked. Autosomal recessive:
This means that the gene for the factor in question is not carried on a sex chromosome. In most cases, the same mutations are inherited by the same means, although there are occasional exceptions to the rules. One example is the lutinos; most inherit sex-linked recessive, but there are also some lutino forms that inherit autosomal recessive (the lutino Princess of Wales parakeet and the lutino Elegant parakeet, for example).

Formulas:
Most color mutations in Australian parakeets may be dealt with either in the autosomal recessive or in the sex-linked recessive form. Autosomal recessive inheritance::
The subjoining mutations follow the same "rules" of inheritance. You only have to replace the yellow mutation from Table I for one of the listed color mutations. Simply by replacing "yellow" in Table I for the following mutations, the results are at your fingertips: Bamard's parakeet -- blue
Bourke's parakeet -- fallow -- yellow
Cockatiel -- pied -- silver -- white face
Elegant parakeet -- lutino
King's parrot -- yellow
Pennant's parakeet -- blue -- yellow -- white
Princess of Wales parakeet -- blue -- lutino -- albino
Rosella -- pastel
Turquoisine parakeet -- yellow
Splendid parakeet -- seagreen
-- pastel blue
-- white-breasted blue
Sex-linked recessive inheritance: The easiest way to explain this inheritance is to study the table below which deals with wild or normal-colored and cinnamon colored parent birds.

E-Mail: berniehansen@sympatico.ca

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Hamilton & District Budgerigar Society Inc.