1. Red-green colour bg 3w l8spv667furdl3se2/usy lindness is caused by an X-linked recessive allele. In the pedigree chart below which individuals must be carriers ouds2g 736fuws8lve y3 pl6/rsf the red-green colour blindness allele?

  2. If the parents in the pedigree chart above had.*cj-5s -rdza uubrn/dv/m5 a a fourth child who was female, what b- md su 55cjv-.aa*u/r/dnzrwould be the probability that she was colour blind?

  3. In Labrador dogs, black coat is dominant over chocolate coat. The genotypeiv1j*wk3+; rqk -alii0u( anv of a black male labrador is unknown. How can the vuvl+;(an - 1*a3jrk0qiw iik genotype of this black Labrador be determined?

  4. Which of the following best mbejuk 1-eyg;rbo(v2pr ;, o6 defines the term, “gene”?

  5. Phenylketonuria (PKU) is an inherib5ib70dg-o t lted human disease caused by a recessive autosomal allele in a gene which codes forlt 5 ibg7d0bo- an enzyme needed to convert phenylalanine to tyrosine. The PKU 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 the alleles, yellow or grj hwe9;amml- 67okd7 iefw v*,een, is dominant.

ii. Deduce the genotype1cyrg 1rczc+. of the offspring.

Iii. Construct a Punnet grid to show the cross between two offspring plant58acruyw2-j42n8yh pt1 - g: jyxxaabs of the F1 - y8ny2x24a8:ta wgpxj5 1rjbhc -uaygeneration.

Iv. Deduce the phenotypic ratio for thcc *;sqo6cmjpv0 )x, ie offspring of the F1 cross.

7. Amand has a daughter with Padmavathi. Amand is blood group Ap-s/ x rqdlmk0p56 fm*, Padmavathi is blood group B, and their daughter is blood group5kdp0 lm-x*rsf/p m6q O. They are 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 fact4lk+nxeo : (cpors can interact in a phenotype to cause the appearance of human skin (p+k:ne clx4 ocolour.

a. Deduce genotypes for the three coat3+ h .+ 2f bpppc(h/igsitvtjh)o-9zy 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 co4t5fxw, rw t-wv:g7g yw in the image.
Use P for the allele for polled and p for the allele for horns.

c. The roan colour, polled y;h(tqfb,z(k ny9ij- ms 469icpk 4 pwcow in the image is mated with a white coat, horned bullp,4 iin(k-;49yhztwfs bcpm q 9yj6(k.
Construct a Punnett square showing all possible phenotypes of the offspring.

10. The pedigree chart shows ABO blood group alle7iy0pmidja5 ( les and their genotype for nail-patella syndrome, an inherited condition. The indiviai md70( pyj5iduals 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.