The last years we examined several breeding records of *dominant yellow* Agapornis fischeri. It soon became clear that this phenotype (mutation) has a dominant expression, but not all youngster are *yellow*. We also have *misty* and *edged* youngsters. Breeding outcomes helped us to exclude a sex-linked dominant inheritance.
Because we have several phenotypes in * dominant yellow* and there are no clear SF or DF phenotypes, we believe that this mutation has most probably a variable expressivity and, POSSIBLE, a reduced penetrance, but reduced penetrance is something that definitely needs further examination.
Variable expressivity refers to the different phenotypes that can occur in the carriers of this mutation and can explain the different phenotypes in the offspring of *dominant yellow*.
Reduced penetrance means the genetic trait is expressed in only part of the youngsters (who have that *dominant yellow* mutation / gene), but again this is still not sure.
Reduced penetrance and variable expressivity usually affect mutations that have an autosomal dominant pattern of inheritance, although they are occasionally seen in mutations with an autosomal recessive inheritance pattern.
So we are still looking for further breeding records and we would like to ask serious breeders to do some extra test matings to help us to confirm / debounce this theory. Any information is welcome. Interesting to know is:
– complete genome of the parents (colour and splitfactors)
– the colour of all chicks in the clutch, sex of these chicks.
– The colour and the sex of the offspring from these chicks, even if they are not *dominant yellow*
Ideal is a pedigree of two or three generations offspring from *dominant yellow*, even from the green youngsters.
Thanks in advance