Definitions of Words used in the Articles
Research & Advice Group, The Netherlands
- A group of inherited conditions which include a decrease in the amount of
- the eyes, skin and feathers.
- Just a specific variation of a gene
- Referring to a chromosome other than one of the sex (Z or W) chromosomes.
- The container for chromosomes. A Budgerigar cell carries at least 30 chromosomes in
- a gamete cell or at least 30 chromosome pairs in all other cells.
- A microscopic structure, made out of DNA, which carries the genes. All cells
- the body have a set of chromosomes. Each chromosome contains a large number of
- genes except for the W-chromosome in female birds.
- The lack of dominant or recessive traits allowing both alleles in a chromosome pair to
- express themselves.
- A cross section is a cut through something (such as a feather shaft) at an angle perpendicular to its axis in order to
its interior structure.
- When a pair of chromosomes trade genes.
- Desoxyribonucleic acid, a natural substance which stores genetic information as an
intertwined double chain. The body reads the code stored in this chain to learn how to
assamble proteins from amino acids.
- The opposite of recessive. A gene that is visible when paired with other genes. The
- most expressive gene at the allele of a chromosome pair.
- Dihychoxyphenylalanine, a natural chemical which the body makes as a step in the
process of making the pigment melanin.
- The suppression of a gene by the effect of an unrelated (epistatic) gene.
- A black or brown form of the pigment melanin as is to be found in e.g. Budgerigars.
- The "root" of a bird feather, from which growth and coloration of the feather
- Featherbulbs go through moulting cycles, and when moulting or the feather is
- out, a new one starts to grow after three days.
- A piece of information, stored in a code in DNA, which tells the body how to make a
- Hens, having only one copy of the Z-chromosome or a human male having only one copy of the Y-chromosome.
- A general term for decreased or total absence of pigmentation or coloration.
- The inability of a gene to produce its usual effect when coupled with another gene that is epistatic
- Such a gene is called hypostatic.
- The normally white colored part visible in the eyes of Budgerigars, which closes in and
opens out around the pupil.
- A location on a chromosome or chromosome pair. A specific place that defines an
- A type of pigment made in the eyes, skin and feathers.
- A type of cell specialized to make the pigment melanin. Melanocytes are
located in the
- skin, the featherbulbs and the eyes. Researchers have found melanocytes in the
- featherbulbs and eyes of birds with albinism.
- A pigmentgranule within the melanocyte and/or within the featherbarbules.
- A chromosome that is almost to small to positively identify as a chromosome.
- Therefore the exact number of chromosomes in the Budgerigar is higher than in most
- reference books.
- Secondary genes that modify the expressivity of a co-dominant or dominant gene.
- A reddish or foxbrown form of the pigment melanin which has never been
- psittacine species.
- The appearance. What the dominant genes express.
- A coloring matter. Pigment absorbs light in the medullas of the featherbarbules.
- sees the light that is not absorbed but reflected back.
- The control by a single gene of several distinct and seemingly
- unrelated phenotypic effects.
- Referring to an altered gene which does not shows its effect if the bird carrying
- gene also has an unaltered gene.
- The surface on the inside of the back of the eye. Light enters the eye through the
- and the lens focuses the light on the retina. The retina converts the light to a message to
- Any gene on the Z-chromosome.
- A set of creatures which, in their natural setting, breed among themselves.
- Segment of DNA that moves to a new location in a chromosome, or to another chromosome,
and alters the
- existing genetic instructions, sometimes producing significant changes.
- They are able to trigger changes in gene expression by shutting of genes or causing insertion mutations.
- An amino acid used by the system to make melanin.
- An enzyme or specialized protein substance in the pigment cell which promotes
the conversion of the amino acid tyrosine to DOPA in the process of making pigment.
- Referred to a gene that is passed on with the Z-chromosome. Male birds have two
Z-chromosomes, while female birds have one Z-chromosome.
MUTAVI Research & Advice Group