Gallo BRAMA BIANCO COLUMBIA* Gallina BRAHMA PERNICIATA A MAGLIE NERE....
Is like Tünde explained all F1 will be bianco Columbia with one allel Co/co+ and carrier of one allele Pg/pg+
Co is dominant over Pg (is why in phenotype we see bianco Columbia)
The male will look some kind good bianco Columbia.
The female will look some kind of "dirty" bianco Columbia.
Depending on the fact if the parents where carriers of other alleles (for ex. both carrier of one recessive white allel) these two c/C+ alleles can come together as c/c and this is "epistatic" (dominant) over Co and Pg so than will let see in phenotype a "White Brahma".
In second generation when the father bianco Columbia (Co/Co) will be breed back on a daughter (Co/co+) 50% of all F2 will be pure (homozygote) Co/Co bianco Columbia(in both sexes) and 50% will be unpure (heterozygote) Co/co+ bianco Columbia. The unpure males (Co/co+) of these last almost not to be distinguished from the pure males (Co/Co), but the unpure females Co/co+) will be some kind of "dirty" bianco Columbia and very good be distinguised from the pure females (Co/Co).
I hope to have given a clear answer to your question and if a smart person can translate my text to Italian because for me it is still imposible.
[Modificato da Danny_57 28/08/2009 11:36]