That was certainly an interesting article to help put things into
perspective and help explain some of the problems we have to deal with now.
Their arguments about extrapolating exact locus function from the
function lost by mutant colour morphs are important to consider.
However statements like
>"We shall refer to mutated genes as actual genes producing definite
>effects, and not as absences of biochemical processes
Have lead to our current situation where many breeders think a gene
controlling a lutino mutation is creating yellow colour, etc. At the most
basic level of learning about colour morphs this idea is acceptable, but not
if we are truely trying to understand what is happening under the influence
of various mutations, nor if we wish to explore the action of a single locus
across more than one species.
It also creates confusion for breeders if we concentrate only on
phenotypes because many different but distinct genotypes create similar
phenotypes, particularly when our study crosses multiple species.
If the authors had known of the vast array of mutations in so many
species of birds that we have today, their approach may have been a little
So whilst it is a good point to remember that the precise point of
action of a particular wildtype allele cannot always be identified fully, we
have progressed beyond the simplistic view suggested in the article.