Adog breeder liked yellow and brown labrador retrievers. in an attempt to produce yellow and brown puppies, he mated a yellow labrador male and a brown labrador female. unfortunately, all the puppies produced in this cross were black. (see pp. 117–119 for a discussion of the genetic basis of coat color in labrador retrievers.) a. explain this result. b. how might the breeder go about producing yellow and brown labradors?

For question a, Labrador retrievers vary in two loci, B and E. Black dogs have dominant alleles at both loci (B-E-), brown dogs have bbE-, and yellow dogs have B-ee or bbee. Since all the puppies were black, a dominant E allele from the brown parent and they must all have inherited a dominant B allele from the yellow parent. The yellow male must have been BBee, and the brown female parent must have been bbEE. The black puppies were all BbEe.

For question b, simply mating yellow with yellow will produce all yellow Labrador puppies. If at least one of the parents is homozygous EE, mating two brown Labradors will produce either all brown puppies, or ¾ brown and ¼ yellow if both parents are heterozygous Ee.

hi my name is ashlynn and im 15

these macromolecules could either be amino acids, proteins or nucleic acids. they are responsible for the chemical changes and reactions that affects largely the cell and its composition. take for instance the cytoplasm of the cell where these organelles are settled. these simple organelles are composed of macromolecules which ignites and catalyses different functions that enables cells, in macro-perspective in motion and metabolism. in intestines for example, metabolism happens and breaking down parts of a food to simpler compounds that are used and these nutrients delivered throughout the body and again broken down by into smaller components.