The first is that the effect of a mutation (dot variations of the DNA structure of a chromosome) can manifest itself suddenly in any generation with traits that are so precise and clear-cut that selection may require few, sometimes very few, generations, both in Nature itself and when carried out by Man. Examples of this in the domestic state as regards the canary are the appearance of the tuft and the brown colour of the entire plumage, or alternatively the disappearance of lipochromes (Whites) or their lightening (Ivories), etc. All ìvariations on the themeî due to mutations which breeders are familiar with.

In these cases identification of the genetic dominance or recessivity of a specific factor guides the breeder in the selection process. Basically, either yes or no: either the trait appears or it does not appear. Or in a third, rather particular case, it is segregated and reappears in exactly the same form in subsequent generation(s) (recessive character). There are no other basic alternatives. This is the so-called Mendelian heredity described in relation to green and yellow peas in Mendelís laws.

Perhaps I should point out right now that this heredity does not concern the Italian Giant Frill, except as regards the acquisition of certain colours like white, brown and a few others, which is common to all the other breeds.

The second point, which for the Italian Giant Frill in particular is of fundamental importance, is that certain mutations can give rise to exterior manifestations (the phenotype!) that are so minute that they may at first pass unobserved. But we need to be clear about the fact that we are dealing with variations in DNA here! Just that they have limited effects. But these ìsmall eventsî, which at the time might go unnoticed, can gradually accrue with time and finally become noticeable and then even be selected, thereby giving rise over a long period of time to new breeds and, in Nature, to new species. This is the so-called quantitative heredity. This really does concern the Italian Giant Frill! Examples of this include variations in size, the development of individual feathers, an increase or decrease in the number of eggs laid, and so on. The value of these factors can be measured with common units of measurement (length, weight, number, etc.).