1. Red-green colour blindness is caused by an X-linked recessive allele. In the /60 4wubt p;x)ioy9+ 6yny0amkzreos/py+;xotzy9rkny 4 m60 6u0 waei o)sbpedigree chart below which individuals must be carriers of the red-green colour blindness allele?

  2. If the parents in the pedigree chart above had a fourth child who was fexa-: 8prh4a, /wq fabck)e aj)male, what would be ,kj: 8-/xc4ba) aqfap whe)ar the probability that she was colour blind?

  3. In Labrador dogs, black coat is dominant over chocolate c8 xzpy( hxbyuv t2k aou7*/m,9oat. The genotype of a black male labrador is unknown. How can the genotyzukm*p 2yot ,xvy79a xhb/u(8pe of this black Labrador be determined?

  4. Which of the following best define+lg,gbnr90m gl d,ld o 6(kbg 5dnul72s the term, “gene”?

  5. Phenylketonuria (PKU) is an inherited human disease caused by a recessive autyhvnk) mk *h kya34a*3osomal allele in a gene which codes for h43mv* ay kh*)aykn k3an 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 green, is doalzxc 0xyp):6 mn r8z3minant.

ii. Deduce the genotype of t7jhnfs/0ut. nj*s 9urhe offspring.

Iii. Construct a Punnet grid to sho 6 h9)yyus1rrtmx /1lhw the cross between two offspring plants of the1s9m tru/x)1lr 6hhyy F1 generation.

Iv. Deduce the phenotypicx0r0rke 0c +9so3jhki ratio for the offspring of the F1 cross.

7. Amand has a daughter with Padmav1h(y7znlz.dh *j6 fmkathi. Amand is blood group A, Padmavathi is blood group B, and their daughter is blood group O. They are having a second childz. f*l67h1ydj z(mnkh , 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 pheno q es6c0m)dff2type to cause the appearance of human 6f2)dcm0se q fskin colour.

a. Deduce genotypes for the three coat colour phenot/ys,mrfjw(6i, gei:yypes 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 wrcnbn-kz(1di,44 ct of the 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 mated with a white coat, horn/j//mwi dl3p/sd-d+/ qdvptaz, itl+ed bull. -+tsa //t/,dvqdd3+iip mld p jz/ w/l
Construct a Punnett square showing all possible phenotypes of the offspring.

10. The pedigree chart shows ABO blood group alleles and their genotkcvu2*m5,oij hg6kq7 f 3r9;y ,aezdnype for nail-patella syndrome, an inherited condition.ocg,,3dker qm*vyj9 n7 6a5u;2hkzif 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.