Sex-linked Recessive Mutation
- Sex-linked - locus of the mutation gene is located at the X-chromosome.
Chromosomes are in pair and in birds it is the female who has only one X chromosome
X and one Y, which makes her to be a female. Therefore
female cannot "split" to the mutation - either has the mutation gene and the mutation
can express itself or does not.
- Recessive - mutation gene cannot overrule the second from the pair.
In order the mutation could express itself, there must be both mutation preset in the bird.
If there is only one, the mutation will not be visually detectable and the bird
is only so-called split to the mutation.
- From the above it follows, it is necessary, both parent would carry at least
one mutation gene to produce a mutant male, to produce mutant female, only a split male
is needed. Let's assign X to the mutation gene and x
to the normal one. Then the mutated bird can be produced from the following matings:
-
XX x XY = 100% mutated offsprings
XX x xY = 100% mut. females 100% split males
Xx x XY = 50% mut. females, 50% mut. males
+ 50% split males
Xx x xY = 50% mut. females 50% split males
- - - - - -
xx x XY = 100% normal fem. 100% split males
Sex-linked Incomplete Dominant Mutation
- Sex-linked - locus of the mutation gene is located at the X-chromosome.
Chromosomes are in pair and in birds it is the female who has only one X chromosome
X and one Y, which makes her to be a female. Therefore
female cannot "split" to the mutation - either has the mutation gene and the mutation
can express itself or does not.
- Incomplete Dominant - mutated gene can partially overrule the second from the pair,
so the presence of only one mutated gene is sufficient for the mutation to express.
However, it will not express in the full way, for that both mutation genes are necessary.
Than the bird is called double factored(df).
If only one mutation gene is present is called single factored(sf)
and the bird looks somewhere between the mutant and normal appearance.
Autosomal Recessive Mutation
- Autosomal - locus of the mutation gene is not at sex chromosome.
X or Y
- Recessive - mutation gene cannot overrule the second from the pair.
In order the mutation could express itself, there must be both mutation preset in the bird.
If there is only one, the mutation will not be visually detectable and the bird
is only so-called split to the mutation.
- In order to produce a mutated bird, both parent must carry at least one mutation gene.
Let's assign X to the mutation gene and x
to the normal one. Then the mutated bird can be produced from the following matings:
-
XX x XX = 100% mutated offsprings
XX x Xx = 50% mutated 50% split
Xx x Xx = 25% mutated 50% split
- - - - - -
XX x xx = 100% split
Xx x xx = only 50% split
The sex of the parents is irrelevant.
Autosomal Dominant Mutation
- Autosomal - locus of the mutation gene is not at sex chromosome.
X or Y
- Dominant - mutation gene can overrule the second from the pair,
so the presence of only one mutated gene is sufficient for the mutation to express.
According to the number of mutation genes single factor(sf) and
double factor(df) birds ca be distingush. Visually, they look the
same the only difference is in inheritance.
- In order to produce a mutated bird, it is sufficient to have at least one single factor parent.
Let's assign (sf) to the single factor bird,
(df) to the double factor bird, and xx to a normal one.
Then the mutated bird can be produced from the following matings:
-
(df) x (df) = 100% (df)
(df) x (sf) = 50% (df) 50% (sf)
(df) x xx = 100% (sf)
(sf) x (sf) = 25% (df) 50% (sf) 25% xx
(sf) x xx = 50% (sf) 50% xx
The sex of the parents is irrelevant.
Autosomal Incomplete Dominant Mutation
- Autosomal - locus of the mutation gene is not at sex chromosome.
X or Y
- Incomplete Dominant - mutated gene can partially overrule the second from the pair,
so the presence of only one mutated gene is sufficient for the mutation to express.
However, it will not express in the full way, for that both mutation genes are necessary.
Than the bird is called double factored(df).
If only one mutation gene is present is called single factored(sf)
and the bird looks somewhere between the mutant and normal appearance.
- In order to produce a (sf) mutated bird,
it is sufficient to have at least one single factor parent.
Let's assign (sf) to the single factor bird,
(df) to the double factor bird, and xx to a normal one.
Then the mutated bird can be produced from the following matings:
-
(df) x (df) = 100% (df)
(df) x (sf) = 50% (df) 50% (sf)
(df) x xx = 100% (sf)
(sf) x (sf) = 25% (df) 50% (sf) 25% xx
(sf) x xx = 50% (sf) 50% xx
The sex of the parents is irrelevant.
Co-dominant Mutation
- It is the situation, when there is a lack of dominant or recessive behavior between
two Multiple Alleles (mutant alleles belonging to one locus).
Once the bird has both mutation genes (one from each mutation) it is visually
half the way between the two appearaces. In the name both names are
written together without separation by a space, for example "pallidIno".
- The mutation itself can be of any mode - Recessive, Sex-linked Recessive,
Dominant, or Incoplete Dominant towards the normal (non-mutant) color.
Lethal Semi Dominant
- Lethal - mutation does not go along with live - homozygot bird,
having two mutation genes die. Often before hathching.
- Semi Dominant - because of the fack mentioned above, there are
only single factor(sf) birds with one muation gene, where
the mutation can express itself.
- We have only two possibilities for mating. It is recomended to always mate
a normal bird to single factor bird. In the second case the double factored
(df) offsprings die.
- Let's assign (sf) to the single factor bird,
(df) to the double factor bird, and xx to a normal one.
Then the mutated bird can be produced from the following matings:
(sf) x (sf) = 25% (df) 50% (sf) 25% xx
(sf) x xx = 50% (sf) 50% xx
The sex of the parents is irrelevant.
Multiple Alleles
- - when more then one mutant allele (an alternative gene for particularr locus) exists.
Since they all belong to the same locus a bird can have at maximum two of them at the same time.
- A situation, when there is no natural gene, but only two different alleles may occur.
Then eather one is dominant over the other and it will express itself or they can be
co-dominant and the resulting feather color will be a blend between those two.
Crossover
- Is a mechanism where two homologous chromosomes can exchange a sequence of genes of the same length
containing the same loci and re-assort so their combination of genes(alleles). This accures during meioses
- a stage where sister chromatids are formed. It can occure several times possibly produsing multi crossovers.
The rate at which the crossover can accure for two given mutations is called a Recombinant frequency.
Too many resulting combinations
- The number of all possible outcomes can double or triple with every new mutation selected.
-
normal x split or (sf) => 2x
visual or (df) x split or (sf) => 2x
split or (sf) x split or (sf) => 3x
- Selecting many mutations can lead to a very large number of possible outcomes.
For exapmle, both parrents split for 4 the same mutations can result into 81 (3^4) and
for 5 even into 243 (3^5) different output combinations.
However, most of them will differ only in the number of mutations they split to.
In this case check "Visuals only". In case of dom. mutation (no splits)
leave out the not important mutations.
-
There is a software limit, because of the calculation time.
Having a large number of resulting combinations wouldn't be useful anyway.
Dark-blue chromosome
- Similarly, as the sex-linked mutations are all linked to the one chromosome,
the loci of blue and dark mutations appear to be linked to another autosomal
(non-sex) chromosome. Therefore there is an influence on inheritance,
when a bird has one mutation gene for both mutations (single factor dark and splits
for blue).Two different situations can occur:
- Type 1 (T1) - both mutation genes are at the same chromosome
in the chromosome pair. XD-blX
- Type 2 (T2) - the mutant genes are on different chromosomes
in the pair. XD Xbl