Glossary Of Terms I

Glossary of Terms Part I
14th July 2011, 8:31 am

.Multiple Allelic Series - A set of three or more alleles potentially able to be expressed at a
given locus. In a diploid organism like birds, only two alleles or genetic variants can be pres-
ent at one time. Examples: LB, R CFW and C CFW in the Zebra Finch or the human ABO
blood typing system.

Nonsex-Linked Ino - The Ino mutation when it occurs on an autosome (chromosome other
than the sex chromosomes).

Ocular Albinism (Hypopigmentation) - Extremely reduced or the complete absence of eye pig-
ments. Commonly called red eyed.

Oculocutaneous Albinism - Extremely reduced or the complete absence of eye and body pig-
ments. See “Ino” and “Albino.”

Par-Ino - Literally 'partial Ino'. Creamino and Lutino are par-inos as they retain residual
melanin pigments. Albino is a full Ino.

Pearlino - In Societies, a hypothetical crossover mutation between Creamino and Pearl. Both
loci are located on the same Z (X) sex chromosome.

Phaeomelanin - One of two major classes of melanin. Phaeomelanin is typically reddish
brown, rust or warm chestnut in color though it can appear bright red or even yellow in certain
circumstances. Human red hair and wild type Zebra Finch cheek patches contain a very high
proportion of phaeomelanin pigments.

Phenotype - The visual or measurable characteristics of an individual bird or an individual
gene. Outward appearance. Gene expression we can see or measure.

Phino - Literally 'phaeomelanin Ino'. An autosomal mutation that results in the complete
reduction of eumelanin in the Zebra Finch. Phinos only had orange markings and were simi-
lar in appearance to the double factored Florida Fancy, only Phinos had red eyes. This muta-
tion was lost.

Progeny - The immediate or first generation offspring from sexual reproduction.

R CFW/C CFW - A male zebra finch which carries both CFW alleles, or put another way, a
male Zebra Finch which is split for both CFW mutations. A hen can never be R CFW/C CFW.
An R CFW/C CFW has an intermediate phenotype. Which CFW is written first is arbitrary. It
could just as easily be written C CFW/R CFW.

Recessive - A mutant allele which is masked by a dominant or visible allele. An individual
must receive two recessive alleles, one from each parent, in order to see the hidden or reces-
sive mutant phenotype. Examples: White Breasted in Gouldians, Gray in Societies or White in
Zebras. The most common form of a mutation.

Recombination - Commonly called crossover. The exchange of portions of homologous
(matched) chromosomes during the formation of gametes (eggs and sperm). There is no
genetic recombination on the W (Y) chromosome in female birds because the Z (X) and W (Y)
chromosomes are not homologous.

Red Brown - Aka Foxy Red or Red Fox. Rich intense reddish brown shade of Euro
Bengalese Finch. In American Societies. Fawn is the Red Brown analog. See “Euro.”

Red eyed - Eyes which lack most or all of the typical pigments as found in the wild type. Red
eyes have a pinkish red color similar to albino rabbits, rats or mice. Red eyed is not to be
confused with maroon or deep red eye color.

Segregation - The occurrence of different phenotypes amongst progeny. Also, the separation
of homologous chromosomes during gamete (sperm or egg) formation. Put another way, the
separation of paired genes during germ cell formation. Mendel's first law of genetic inheri-
tance.

Selection - The act of determining which phenotypic traits a breeder prefers. One can select
for a preferred trait and keep birds with a certain characteristic, or one can select against
undesirable traits and cull these birds.

Sex Chromosomes - Determine which gender an organism will be. In birds and butterflies,
these are the Z or W chromosomes rather than the X or Y chromosomes as they are com-
monly referred to in most other organisms. Sex determination is still unclear in birds, however
ZZ (XX) constitutes the male gender, while ZW (XY) determines the hen's gender. Remember
that sex determination is the opposite in birds than it is for mammals.

Sex-Linked - A mutation which occurs on the Z (X) chromosome in birds.

Sex-Linked Co-Dominant - A mutation which occurs on the avian Z (X) sex chromosome and
is inherited in a co-dominant manner. Only one copy of the mutation needs to be present in
order to see partial expression of the mutation or color. Example: single factored Yellow
Bodied in purple breasted male Gouldians.

Sex-Linked Dominant - A mutation which occurs on the avian Z (X) sex chromosome and is
inherited in a dominant manner. Only one copy of the mutation need be present in order to
see full expression of the mutation or color. Example: Red headed in Gouldians.

Sex-Linked Ino (SL Ino) - Ino mutation that occurs on the avian sex (Z) chromosome. Unlike
NSL-Ino, SL-ino is NOT a mutation in tyrosinase. In fact, SL ino birds have higher than nor-
mal levels of tyrosinase. It is still not clear which enzyme is affected by this mutation.
Melanin production is extremely reduced in SL inos, although there are certain amounts of
residual melanin pigments still synthesized.

Sex-Linked Recessive - A mutation which occurs on the avian Z (X) sex chromosome and is
inherited in a recessive manner. Hens can never be split for any sex-linked mutation, and
they inherit their Z (X) chromosome and any mutations on it ONLY from the father. The moth-
er always gives the W (Y) chromosome to her daughters. In hens, what you see is what you
get with sex-linked mutations. Males can be split for sex-linked recessive mutations.
Example: CFW, LB, Fawn in Zebra Finches, Creamino and Pearl in Societies, Black Headed
in Gouldians.

Single Factor (SF) - A term for co-dominant mutations, when only one mutant allele is present
in an individual. Only one copy of the mutation need be present in order to see partial expres-
sion of the mutation or color. Examples: SF Florida Fancy in Zebra Finches or SF Yellow
Backed purple breasted male Gouldians.



Split - This is the layman's terminology for a heterozygote. Commonly written as dominant
mutation/recessive mutation. Examples: Aa, or Green Backed/Blue Backed in Gouldians.
See “heterozygote.”

Tyrosinase - The rate limiting enzyme absolutely essential for ALL melanin synthesis. If this
enzyme is nonfunctional or mutated, the bird will not be able to make any melanins at all. See
“Albino.”

W Chromsome - The avian female sex chromosome. Female birds have the ZW (XY) geno-
type. The W chromosome would be equivalent to the Y chromosome in humans. Avian sex
determination is the opposite from most species.

White Ground - A bird that appears white when all melanin is removed from its feathers.

Wild Type - The coloration and patterning of a bird as found in the wild. This is the dominant
phenotype. Aka normal.

Yellow Ground - A bird that appears yellow (due to carotenoids) when all melanin is removed
from its feathers.

Z Chromosome - The avian male sex chromosome. Male birds have the ZZ (XX) genotype.
The Z chromosome would be equivalent to the X chromosome in humans. Avian sex determi-
nation is opposite from most species.

Christine ACY Kumar has been breeding Estrildid finches for 5 years. Her passion
lies with color mutational and combinational breeding/selection, and she works
extensively with Zebra, Bengalese & Gouldian Finches, as well as other Australian
Grassfinches and Blue Capped Cordon Blues.


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