Rhodesian Ridgebacks are known for the distinguishing feature ofthe ridge of hair
running along their back in the opposite direction from the rest ofthe coat. Recent
studies have shown this to be due to an autosomal dominant mutationin the \"Ridge\"
gene (i.e., those homozygous recessive for the mutation areridgeless). You have two
ridged dogs (Dog 1 and Dog 2) that you have decided to breed, butyou are uncertain
of their exact genotypes.
1) After breeding your dogs, you observe that out of 10 puppies, 3are ridgeless.
a) What are the possible genotypes of the ridged and ridgelesspuppies {please use
\"R\" and \"r\" to represent the alleles)?
b) Based on these results, what are the genotypes of Dog 1 and Dog2? Explain how
you know this.
2) When looking only at the ridged puppies, can you definitivelydetermine the
genotype of each individual puppy?
3) Devise a breeding experiment that would allow you to determinethe specific
genotype of each ridged puppy. You may breed any of the puppies toeach other or
backcross with a parent (Dog 1 or 2). Please make sure you explainthe rationale of
your breeding crosses (i.e., what outcomes would you expect to seeand how does
this help you determine genotype).