GENERAL GENETICS PRACTICAL SESSION BIO 221 LECTURER ALSHEHRI

GENERAL GENETICS (PRACTICAL SESSION) BIO 221 LECTURER ALSHEHRI, DOKHNAH SAEED DALSHEHRI@UT. EDU. SA

QUESTION 1: • How can the child of two browneyed parents have blue eyes? ( in such case which kind of dominance presents here? . )

QUESTION 2: • If two pea plants hybrid for red color are crossed. What is the expected ratio of flower color among the offspring?

QUESTION 3: • A lethal gene B is found on one of the X chromosomes of an infected female. If she marries a normal male, what is the possibility that their male child will be affected with this gene?

QUESTION 4: • A mother with blood type A and a father with type B blood wish to find out if it is possible for their children to have blood type O. Please explain.

QUESTION 5: • In cattle, black is dominant over red. A farmer wants to know if his black bull is a pure strain. When the black bull was mated with a red cow, over a period of years, several calves were born. Of these calves, approximately 50 were black and 50 were red. What is the genotype of the bull? What is the genotype of the black calves? The red calves? What we called this kind of testing?

QUESTION 6: • 2. A woman with brown eyes and dark hair married to a man with blue eyes and blonde hair. All the children have dark hair, but half have blue eyes and the other half have brown eyes. * Provide the genotypes of the parents and the children. Let (E) represent dominant brown eye colour and (e) recessive blue eye colour. Let (B) represent dominant brown hair colour and (b) recessive blonde hair colour. (Show all your workings in punnet squares).

QUESTION 7: • In a case of disputed parentage , the mother of an illegal child is blood type N, the child MN, and one suspected father is N and the other MN. • How would you work out the case?