Question

In labrador retrievers some puppies have pink nose and some have black labrador retrievers with black for almost always have black noses what type of inheritance pattern is this explain how this is possible?

Answer 1

Complete dominance.

Step-by-step explanation:

In complete dominance, the two alleles interact in such a way that in heterozygosis the expression of one of them is phenotypically "visible" (the dominant), while the other is hidden (recessive). The heterozygote is phenotypically identical and indistinguishable from the dominant homozygote.

There are two pairs of better known genes that control the color of the Labrador's coat. The "B" gene is dominant and responsible for the black coat color, the "b" gene is recessive and responsible for the chocolate coat color. The "e" gene is responsible for the color of the yellow coat, and for this reason it must always appear homozygous (ee), which will inhibit the expression of the other gene pair. So the possible genotypes for the black coat are the following BBEE, BBEe, BbEE, BbEe, the possible genotypes for the chocolate coat are bbEE, bbEe, and the genotypes for the yellow coat are BBee, Bbee, bbee. So if the mating is done with two double heterozygous animals (BbEe) you can have puppies of the three coat colors in the litter.

However, if complete dominance occurs, the puppies will be black with a black face, because the gene for these characteristics is dominant. In that case, there was complete dominance.