In the course of evolution live organisms, adapting to changes of environment, throughout many generations accumulate new dissimilar properties for a long time. Such not inherited properties caused by changes of environment are called modifications.
Pairings as AHA give birds, bright, graceful, but small in size. At a parovka at such birds it is necessary to delete carefully plumage round a foul place as the dense plumage often interferes with normal fertilization.
Connection of factors of P and B causes imaginary exceptions to the rules. In this case some genotypes have a combination of genes. In the list of genotypes there are designations "1 and 2 types". On external signs these birds are indiscernible, but they are very various on the hereditary properties.
Pairing as VHV gives posterity of larger sizes, but a bad exterior. Long pairing on this type conducts to emergence in each new generation of quickly accruing degeneration signs.
"Yellow and Buff" - is literally translated, as "yellow and pale yellow". Kanarovoda which adhere to the rule long enough use the theory: "Couple birds of bright coloring to birds of pale coloring". In the international practice of birds with intensive coloring designate a symbol And, and birds with not intensive coloring - Century. So, speaking to language of symbols, the theory suggests to parovat birds as AHV.