FAQ: how can we determine that we are indeed dealing with a new mutation?
On a weekly basis I receive photographs of birds with a (presumably) deviating colour and always the same question: what is this and is it a new mutation? Unfortunately it is not possible to determine this based on a photograph. Others send me feathers but even this is not sufficient to form a well-founded conclusion.
The first question is whether the deviating colour is indeed a (new?) mutation and not a modification or a combination of existing mutations? There fore the pedigree of the parents, and if possible of the ancestors, is crucial. We can use this to easily look at all possibilities. If there is no reason to assume that we are dealing with a mutation combination we come to the next question: is the phenotype really a mutation and not a modification?
Admittedly, this sound very simplistic but it is an important question: does this deviating type inherit? Everything depends on this. If we can determine that the phenotype does indeed inherit our first job is to figure out how this inheritance occurs. The only correct way is to mate this possible new mutant with green wild-type and it usually takes a few generations before we are 100 percent sure. But fortunately purposeful trial pairings will tell us over time which locus is really involved in this mutation. Once the inheritance method has been determined we can start comparing these to existing mutations in other species based on the genotype and the phenotype to try and figure out which mutation we are dealing with. If that does not provide an clear answer, we have to proceed with further feather or DNA research.