In Labrador retrievers, two genes work together to determine coat colour.The first gene affects the colour of the dark pigment, eumelanin. A genotype containing at least one dominant allele of this pigment gene results in black pigmentation (B_). A homozygous recessive genotype of this gene results in chocolate (brown) pigmentation. The second gene affects whether the pigment eumelanin is present in the fur. If a dog has one dominant allele for this expression gene (E_), fur colouration is determined by the pigment gene. If a dog is homozygous recessive for the extension trait, the dog will have a yellow coat. Description Genotype(s) Black coat B_E_ Chocolate coat bbE_ Yellow coat _ _ ee   Predict the percentage of offspring that would be black in colour for each of the following crosses. Record your answer as a whole number. Cross: BbEe x BBEe  BbEE x BbEE  Percentage of Offspring: Answer% Answer%

Labrador retrievers are commonly black, brown, or yellow. Two different genes determine coat color in Labrador retrievers. The B gene determines pigment color (B is black, bb is brown). The E gene determines whether the pigment can be deposited in the hair shaft: ee prevents any pigment from being deposited, resulting in yellow dogs. You want to breed Labrador retrievers, and you cross a true-breeding brown Labrador retriever to a true-breeding yellow Labrador retriever. All 15 of the F1 puppies are black. After the puppies grow up, you cross two of the F1 black dogs together. In the F2 generation you get 8 black puppies, 4 yellow puppies, and 3 brown puppies. Part 1 What is/are the possible genotype(s) of the true-breeding brown lab in the P generation? O bbEE Brown bbee O bbEe Could be either answer bbEE or bbEe Part 2 What is/are the possible genotype(s) of the true-breeding yellow lab in the P generation? Obbee Bbee BBee Could be either bbee or Bbee. O Could be either Bbee or BBee.…

In the red backed vole (a small mouse-like mammal) there are two traits under investigation.  The first trait is a distinct tuft of long hairs at the tip of the tail with a tufted tail being recessive to non-tufted tail.  The letter T is used to represent the tail tuft gene.  The second trait is a patch of red fur on the head which is known to be recessive to the more common lack of a red patch.  The letter R is used to represent this trait.  A female to be used in the cross was drawn from a pure breeding line that consistently has both the red patch on the head and a tufted tail.  The female is to be crossed with a male from a highly variable wild population.  The male used had no red head patch and a normal (untufted) tail.  The results were as follows:  7 red head patch with tail tuft, 8 no red head patch with tail tuft, 8 red head patch without tail tuft, 8 no red head patch without tail tuft.  What would the results be if the male was crossed with a female that was known to be…

In a poultry breed, chickens can have black, blue or white feathers. The different feather colors are determined by interactions between genes at two loci. One locus determines the type of pigment produced by the skin cells: a dominant allele B encodes black pigment, whereas a recessive allele b encodes blue pigment. Alleles at a second locus affect the deposition of the pigment onto the feathers. Allele E allows dark pigment (black or blue) to be deposited, whereas the homozygous recessive (ee) condition prevents the deposition of dark pigment, causing the feathers to be white. In each of the following 3 crosses give the genotypes and phenotypes of the parents and their offspring: a) Two black birds that are both heterozygous for traits B and E b) Two blue birds that produce 6 blue and 2 white chicks c) A black bird that is homozygous dominant for both traits and a white bird that is homozygous recessive for both traits