1. Red-green colour blindness is caused by an X-linked recessive a kegt )w;fa5 eo(sz:bd 6o5)dnllele. In the pedigree chart below which individuals must:do)tna fe5k5b)(z 6soe; wgd be carriers of the red-green colour blindness allele?

  2. If the parents in the pedigree chart above had a fourth child wh bx5 mxj8pk*a:fc0.q vo was female, what would be thjp.:b f* 58k0caxxvq me probability that she was colour blind?

  3. In Labrador dogs, black coat is doayye9a/jqa 3* minant over chocolate coat. The genotype of a black male 9yj aaa/3yq e*labrador is unknown. How can the genotype of this black Labrador be determined?

  4. Which of the following best defines the terc+uwco 295v 8ytkxvjb -08pidm, “gene”?

  5. Phenylketonuria (PKU) is an inherited human disease caused by51awat 6jqu/v5(o,/ btaaysw a recessive autosomal allele in a gene which codes for an enzyme needed to convert phenylalanine to tyrosine. The PKa6qs,a /5/uow tw jva(b t51yaU allele produces a non-functional enzyme.
Which of the following statements are correct?
I. Two parents heterozygous for the condition could have a child with PKU.
II. If the mother of the child is homozygous and not affected by PKU, her children will not be affected.
III. The polypeptide sequence of the enzyme of an affected person is identical to a person without the condition.
IV. Two parents who are not affected with PKU cannot have a child with the disorder.

I. Identify which of thp)s d.,.rugdah o2lisy/q 4i3 e alleles, yellow or green, is dominant.

ii. Deduce the genotype o9k. h,emcri.x yq c8w 7uc8/tarud 67wf the offspring.

Iii. Construct a Punnet gri:yctq6 )1ggf oak ewf,3f0(lmd to show the cross between two offspring plants of the F1 genfa:gg (, 0mflwo)yc f1 t3ek6qeration.

Iv. Deduce the phenotypic ratio for the y6 qrx5f4 (jcy;z *(vklriz.loffspring of the F1 cross.

7. Amand has a daughter with Padmava99ysx-jet/d wthi. Amand is blood group A, Padmavathi is blood group B, and their daughter is blood group O. They are yet/wj9-s9xd having a second child, a son.
Deduce the probability that their unborn son will be blood group O. Explain your working.

8. Explain how inheritance and environmental factors can interact in a phenotmysl6ha uv o kl6-527type to cause the appearance of human skink- 7ml6ty as6o5 uhl2v colour.

a. Deduce genotypes for the three cd0 g a+x0f9ugqoat colour phenotypes in these cattle.
Use the symbols $C^W$ for the white coat allele, and $C^R$for red coat allele.

b. Deduce the parental genotypes of the cow in the;0i e1jvy26:qe fg mbx image.
Use P for the allele for polled and p for the allele for horns.

c. The roan colour, polled cow in the image is mated with a white coat, 1s:pyr sh kww- *,zp*thorned bullwps*ywr:ptk - ,z 1*hs.
Construct a Punnett square showing all possible phenotypes of the offspring.

10. The pedigree chart shows ABO blood group aibq4 w d5yqyv4e fu+6jgmvx b)8 //mv*lleles and their genotype for nail-patella syndrome, an inherited condition. The individuals 1, 3, and 4 in row III are recoiv+4y*5 6yfvwg d)mbqvj4u8bq/ /mex mbinants. Image by D.B. Pylypiv.

Use the pedigree chart to explain the meaning of gene linkage.