1. Red-green colour blindness is caused by an X-)pc+vj+45s+kjy( vc* jcn i::sshvlh linked recessive allele. In the pedigree chart below which individuals must be carriers of the red-green colour blindness as*+ sjv sv (ckj+:+5 c hy:cl)4ihjnpvllele?

  2. If the parents in te+ 3a61nodm zthe pedigree chart above had a fourth child who was female, what would be the probabilit o6+e3dazm1 nty that she was colour blind?

  3. In Labrador dogs, b /8ct*:4gt4rg*quuuof f/pd black coat is dominant over chocolate coat. The genotype of a bla*q tt :/8/odb4ufcp uuggf 4r*ck male labrador is unknown. How can the genotype of this black Labrador be determined?

  4. Which of the following best defines the term, “ge3yk*1l m8yzu7uaxycpq 4f 85ine”?

  5. Phenylketonuria (PKU) is an inheri2d0n hik0mxbi/ j3- nated human disease caused by a recessive autosomal allele in a gene which codes for an enzyme needed to convert phenylalanine to0i 3 k-bimn0j2hnx/ da 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 green, is domi2ga ascl6y .q;nant.

ii. Deduce the genotypeb(6q/ zyhifo;5zva 2w of the offspring.

Iii. Construct a Punnet grid to show the cross between two offsprin3tx,h 3ga)i /gj/ecqwg plants of the F1 ge) ,jqwa3g tge/ixch3/neration.

Iv. Deduce the phenotypic ratio for the offspring ofnd 0 o1k-a,f nz4a1s9imbluchh26 jb) the F1 cross.

7. Amand has a daughter with Padmavathi. Amand is blood grz8;sep)0;an zq w(sb,hvv vo.oup A, Padmavathi is blood group B, and their daughter is blood grabv;(so;.n,v0) 8zse qzvh wpoup 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 inheri aijjgpg7 ,1epps-x25 eez 1urof0x+4tance and environmental factors can interact in a phenotype to cause the appearance of human skins i aj+x u5pj7gp4fzp1o2 ,re-g0e e1x colour.

a. Deduce genotypes for the three coat colour phenotypes in these cattliit6w .j-o 9lcalfoy7n *)yz*e.
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 imc 3q/rb0pd3 zn 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 i+f0ib + hmefexg;j+( cmm/ iu-29 unoyq v.0dns mated with a white coat, horned bull+ oiqinf; u -d9v jb 2gex.um0m/me0f+yhn +(c.
Construct a Punnett square showing all possible phenotypes of the offspring.

10. The pedigree chart shows ABO ms i/hitao bhic( x 4x z,143na;e;0vvblood group alleles and their genotype for nail-patella syndrome, an inherited condition. The indi hevx ;zxio4(vit,b10 ;cn4am/ si3a hviduals 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.