Mutation parrot: Genetics is the science of heredity that studies the transmission of anatomical, cytological and functional traits from parents to their offspring. In more common terms we can say that it is science that studies the transmission of genes (mutants or not) in living beings. The first laws of genetics were identified by Mendel in 1865.
A mutation is a sudden and always hereditary change that appears in all living things.
There are lots of mutations and composite varieties (combinations of mutations) in many species of Psittacidae including among others; Agapornis (Inseparable); roseicollis (rosegorge aka facefishing), fischeri (Fischer’s), personatus (masked), Neophema (Euphems); elegans (Elegant Parakeet), pulchella (Turquoisine Parakeet), splendida (Splendid Parakeet), Platycercus (Platycerques aka Rosella; eximius (omnicolor), elegans (Pennant), palliceps, Calopsitte Parakeet, Wavy Parakeet, Psittacula k. manillensis (Indian-collared Parakeet), Neopsephotus bourkii (Bourkes Parakeet), Psephotus haematonotus (Red-rumped Parakeet), Forpus coelestis (Celestial Touïs), Bolborynchus lineola (Catherine’s Parakeet)…
A mutation is always transmitted hereditarily and genetically; we cannot therefore “create” a mutation or a mutant gene but we can isolate the mutant gene following its sudden appearance (in breeding or in the wild) by reproducing it according to its own mode of transmission. All mutants are either heterozygous (single-factor = sf = 1 mutant gene) or homozygous (double-factor = df = 2 mutant genes) and all mutant genes are genetically transmissible according to one of the three main known modes of transmission:
It is a mutation of genes on sex chromosomes commonly known as sex-related recessive. In birds, compared to humans the sex chromosomes are reversed: that is to say that here it is the male who has 2 complete chromosomes named XX while the female has 1 complete chromosome X and 1 incomplete Y (on which no genetic information can ever be transmitted)
Here 1 heterozygous male (1 mutant gene) is non-visual for the mutation and commonly referred to as carrier or asymptomatic mutant. 1 homozygous male (2 mutant genes) is visual for the mutation. Females since having only 1 complete sex chromosome where genetic information is therefore present (mutant gene(s) or not) will always visually be what is written on its complete sex chromosome (X) and therefore always heterozygous when mutant since its incomplete sex chromosome (Y) can not contain any genetic information. On the other hand, this last chromosome (Y) is absolutely not useless since it is responsible for determining the sex of the bird which is then always female.
It is a recessive gene mutation present on autosomes or genes containing DNA. Here both sexes (male and female) can be heterozygous (1 mutant gene = carrier = non-visual = asymptomatic) or rather homozygous (2 mutant genes = visual) since they are not mutant genes present on the sex chromosomes but on the autosomes of which both sexes are equally provided.
It should be noted that the Wild-Type (natural color) is always dominant on recessive mutant genes (autosomal or sex-related) except in the only case of 1 homozygous male related to sex since all its female offspring inherit one or the other of its 2 mutant genes and then automatically visually become the mutation inscribed on their complete sex chromosome (X)
Here is an example of a cross-breed involving a recessive-autosomal gene mutation;
Type-Wild X recessive-autosomal (visual so 2 mutant genes): 100% offspring Type-Wild/recessive-autosomal
or with a known mutation: Green X blue: 100% Green/blue (visually Green but asymptomatic carrier of 1 blue gene)
It is a mutation of the Dominant gene present on autosomes or genes containing DNA. A Dominant gene mutation is preferably called a Factor rather than a mutation that is typically recessive. Here we always observe a form of dominance on the Wild Type and this according to whether it is a Dominant-autosomal mutation following one of the 3 distinct modes of dominance;
* Dominant (Complete) where there is complete dominance over the Wild-Type. Here the heterozygous and homozygous are absolutely IDENTICAL. Here is an example of a crossing involving a Dominant Factor:
Wild-Type X dfDominant (doublefactorDominant):
100% sfDominant (single factorDominant) visual
mutant or with a known
Factor (mutation) Green X dfGris-Green
* Dominant-Incomplete where there is incomplete (partial) dominance over the Wild-Type. Here the heterozygote is visually different and ALWAYS of intermediate coloration between the Wild-Type and the homozygote (dfDI). Here is an example of a crossing involving 1 Factor-DI (Dominant-Incomplete):
Type-Wild X dfDominant-Incomplete:
100% sfDominant-Incomplete (Always intermediate between the Wild Type (or other mutation at the base of the crossing) and the dfDI)
or with 1 Known Factor:
Green X dfFuncted (Olive):
100% sfFonçé (Green-Fonçé) (intermediate between TS (Green) and dfDI (Olive)
* Co-Dominant where there is a cooperative phenomenon (hence Co-Dominant) observed only between mutations of a series-alleles-multiples and therefore of the same locus without direct regard to the Type-Wild. In all locus we find a complete mutation and several incomplete (partial) mutations An example of series-alleles-multiple mutations of the same locus:
The blue locus where we find a complete mutation; blue and several blue-incomplete mutations (aka parbleu of partial blue) such as aqua and turquoise (separate mutations and not the same!)
Here the mutants are always double-heterozygous (double-carrier or carrier of 1 mutant gene for each of the crossed mutations) but always visually intermediate between the 2 cross mutations. Since intermediate, the double-heterozygous mutants then form a composite manifold.
It is very important to note and ALWAYS remember that there is on the other hand in co-dominance no homozygous since it is not at the base of a single mutation but of 2 mutations that are crossed. In addition, it is also very important to note and always remember that there is NEVER a phenomenon of dominance/recessivity between mutations of a multiple-alleles series but ALWAYS co-dominance between them.
Here are some examples of crossovers involving the phenomenon of co-dominance between mutations of a series-alleles-multiples of the same locus;
mutation1 X mutation2:
100% variety-composite (ALWAYS intermediate between mutations 1 and 2)
or with known allied mutations:
aqua X turquoise: 100% aquaturquoise (intermediate between aqua and turquoise)
aquaturquoise X aqua: 50% aquaturquoise – 50% aqua
aquaturquoise X turquoise: 50% aquaturquoise – 50% turquoise
Parrot Genome Project