1. Red-green colour blindness is caused by an X-linked recessive allele. In t2inh 9m 5 j 0njkq1pp/fp9ki8 .mncv6hph+nh. he pedigree chart below which individuals must be carriers of the red-green colour blin/ pc n+nn.h qhv .h pnmf99jmp58p60jiki21hkdness allele?

  2. If the parents in the pedigree chart above had a fourth chmachik,:d :l-+bn1lsild who was female, whs,1+la mblik-cd:hn:at would be the probability that she was colour blind?

  3. In Labrador dogs, black coat is domin6d n0+vzp04* ao9gnmcqjr ,wdant over chocolate coat. The genotype of a black male labrador is unknown. How can the genotype of this black Labrador be de q9, g0zcj0nd6n*o4pma+wvrdtermined?

  4. Which of the following best definaue8 sx5/n1bues the term, “gene”?

  5. Phenylketonuria (PKU) is an inherited human disease caused by a recessive au ju0lh*j2y mm9tosomal allele in a gene which codes for an enzyme needed to convert phen*y9u0mm 2jlhj ylalanine 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 greehdu exa05m-r+p36:f 2yg y8wvouif ,ln, is dominant.

ii. Deduce the genotype of thqczd 4g :bzd14;hhdu:e offspring.

Iii. Construct a Punnet grid to shotfm 300)zyxy y/xj8v iw the cross between two offspring plants of the F1 generatiofmvt0y )3yi8j0z xxy/n.

Iv. Deduce the phenotypic rat;izt.gd wif: f jzq *l;,4r*zfio for the offspring of the F1 cross.

7. Amand has a daughter with Padmavathi. Amand is blood group A, myus57xzghf2q ii6;: Padmavathi is blood group B, x:7zifhs yqu5mg;i26 and their daughter is blood group 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 inheritab2j5t x y00rve;nn: 5jbbwy6 jnce and environmental factors can interact in a phenotype to cause the appearance of human sk0ybt2yebjx 0bn :v;j5w 5jn6r in colour.

a. Deduce genotypes for the three coat colour phenotypes in the 16yduq u;47m;ge k2 ts5 gbuv9etw96p jdy8cvse 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 y akyju /ip6ic96jjce;ko)h( i2 :9gtcow in the image.
Use P for the allele for polled and p for the allele for horns.

c. The roan colour, kl w73*nf7 /lfiltn9 i7jlm;p polled cow in the image is mated with a white coat, horned bull.l*7wlmpj;klni 7t7f 3 /i l9nf
Construct a Punnett square showing all possible phenotypes of the offspring.

10. The pedigree chart shows ABOdtsv2b v1.k: 4-.fr drschs5m blood group alleles and their genotype for nail-patella syndrome, an inherited condition. The individuals 1, hk.sm1: .vr4-rsf5dd 2vbtcs 3, and 4 in row III are recombinants. Image by D.B. Pylypiv.

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