genetics

1.     A cat heterozygous for both hair length and coat colour is crossed with a tan coloured cat heterozygous for hair length. If short hair is dominant over long hair and black coat colour is dominant over tan coat colour then determine the following (Show your work) (4 marks)
Multiple Alleles
1.     A man with type A blood marries a woman with type B blood.  Their child has type O blood.  What are the genotypes of these three individuals?  What genotypes and in what frequencies would you expect in the future offspring from this marriage? 
 
 
 
 
 
 
 
Sex Linkage
2.     Tail length in salamanders is controlled by a sex-linked gene.  The heterozygous condition gives tails intermediate in length, whereas long and short tailed individuals are homozygous. (show your work) (4 marks)
a.     What phenotypic ratio is expected from a cross of a long-tailed male and an intermediate-tailed female? 
 
 
 
 
 
 
 
 
 
b.   In addition to sex-linked inheritance, what kind of inheritance is illustrated here?
 
 
 
 
 
c.     Explain which cross (if any) will yield intermediate-tailed male salamander offspring. 
 
 
 
 
 
 
Linked Genes
 

3.     Two genes of a flower, one controlling colour, blue (B) versus white (b) petals and the other controlling round (R) versus oval (r) stamens, are linked and are 10 map units apart.  You cross a homozygous blue-oval plant with a homozygous white-round plant. The resulting F1 progeny are crossed with homozygous white-oval plants and 1000 F2 progeny are obtained.  How many F2 plants of each of the four phenotypes do you expect?