1. Red-green colour blindn3wx vrim9v/ 4xess is caused by an X-linked recessive allele. In the pedigree chart below which individuals must be carriers of the red-green colour blivvimwx4 r3/x 9ndness allele?

  2. If the parents in the pedigree chart above hadigd rp vxx )l/328/koe a fourth child who was female, what would be the xi p/lkg 8ev3rod)x2/probability that she was colour blind?

  3. In Labrador dogs, black coat is dominant over chocolate coat. The genotyp7ja wt8 l+;rwje of a black male labrador is unknown. How can the genotype of this black Labrador be dew7r+;8t j ajwltermined?

  4. Which of the followingrbb8r k+o 1r/j best defines the term, “gene”?

  5. Phenylketonuria (PKU) is an inherited human disease caused by a recessive aov6c 1z6c k*ifutosomal allele in a gene which codes for an enzyme needed to convert phenylalanine to tyrosine. The PKU allele produces c6 vk1oz6*fci 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 the alleles, yebj5 7wip dsp ;,-6apg82cprc)rwzos:llow or green, is dominant.

ii. Deduce the genotyp-ir6ikwhk.du;dlp,igt 9 8 8d e of the offspring.

Iii. Construct a Punnet grid to show the cross between two 0z qem: /et,i.c42e w vq-nnbeoffspring plants of the F1 generation,e etm.i nq 4-wn:eb eq0z2cv/.

Iv. Deduce the phenotypic ratio for the offsv--k+. p swgc)q9 idmmpring of the F1 cross.

7. Amand has a daughter with Padmavathi. Amand is blood groupyjs.2g5xb43r f wb j:r A, Padmavathi is blood group B, and their daughter is blood group O. They are h. s x5j2: wj4byrgfrb3aving 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 fact9c* efwdwh+-:umr d4zors can interact in a phenotype to cause the appearance of human skin colour-4f+w9 c dedw*rmu z:h.

a. Deduce genotypes for the three cos7w zcy e-)ti;at 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 ywu 5v/wqys.51nfaam-( x i.o cow in the 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 matzx +m.6fg/9rxtk4b vw ed with a white coat, horned bulltw mf+b.x4v9rg 6kzx/.
Construct a Punnett square showing all possible phenotypes of the offspring.

10. The pedigree chart shows ABO - 6lht .bxiwfl3:lax(k sx x(n0jhmr xq(-.*qblood group alleles and their genotype for nail-patella syndrome, an inherite:3( bs(am qlk-.nf*tl l6h h. rx-wjxxxq0ix(d condition. The individuals 1, 3, and 4 in row III are recombinants. Image by D.B. Pylypiv.

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