A breeder is interested in a new coat colour in mice. This trait is controlled by a single autosomal gene (Gene T) with two alleles. The T-allele results in a yellow coat colour, while the recessive allele causes a cream coat colour. The breeder has a yellow mouse. Can you suggest how the breeder can determine the genotype (TT or Tt) of his mouse in a single cross? Describe this cross and provide details on how you would interpret the results.

A dog 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.  Q. Explain this result.

Type 1 albinism in humans is a rare hereditary condition associated with a reduced amount of active tyrosinase, an enzyme required for the conversion of the amino acid tyrosine to the dark pigment melanin. In the pedigree above, males are indicated by squares, females by circles and individuals with type 1 albinism are indicated by shading. Use A and a for the dominant (sufficient active tyrosinase) and recessive alleles (absent or insufficient tyrosinase activity), respectively. Remember that, when genotype is not known for a dominant phenotype, an m-dash is used (A- = AA or Aa). Match the genotypes of the indicated family members as specifically as possible based on the pedigree data. Except where necessary to explain the pedigree, assume that the individuals marrying into the family are homozygous wild-type. v Individual A - v Individual B 1. A- v Individual C 2. Aa Individual C v Individual E

Cystic fibrosis (CF) is an autosomal recessive trait. A three-generation pedigree is shown below for a family that carries the mutant allele for cystic fibrosis. Note that carriers are not colored in to allow you to figure out their genotypes.      Normal allele =  F      CF mutant allele =  f        What is the genotype of individual #13? A) ff B) FF C) Ff  D) it is impossible to tell