1. Red-green colour blindness is caused by an X-linky+e 3*vlf6d*6fh ryr ved recessive allele. In the pedigree chaf6*hd6f+rly rve* 3vyrt below which individuals must be carriers of the red-green colour blindness allele?

  2. If the parents in thetd g; -zifnu:)k-ra+d pedigree chart above had a fourth child who was female, what w i u-gkf+:rat)-nd zd;ould be the probability that she was colour blind?

  3. In Labrador dogs, black coat is dominkiva +/fu-d8x ant over chocolate coat. The genotype of a black male labrador is unknown. How can the genotype of th-xa/8d+kf i uvis black Labrador be determined?

  4. Which of the following best l15pxn whly 3p-qjje:+.yvr,defines the term, “gene”?

  5. Phenylketonuria (PKU) is an inherited human disease caused by lan zuw5-.srl* )kq4h a recessive autosomal allele in a gene which codes for an enzyme needed to convert phenylalanine to tyrosine. The PKU allele produces a non-fhwu5arz-l kl) sqn 4.*unctional 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 g 7ml+h9jsq 8hlbr:2xqreen, is dominant.

ii. Deduce the genotype oi155l; *q9lobs:lv k8q y(c8ajmqdc jf the offspring.

Iii. Construct a Punnet grid tlwuf dfhi+7 g5mn)k 2.o show the cross between two offspring plants of t +uw dm5h gklf.7)fin2he F1 generation.

Iv. Deduce the phenotypic ratio for the offspring of the F1 cros6)n2nn +pesvd s.

7. Amand has a daughter with Padmavathi. Amand is blmb-f8xm5;tim; o wk j2ood group A, Padmavathi is blood group B, and their daughter is blood group O. They are having a second child, at m-o;x f;28kmijwb5m 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 inhegnq 8km,.i(gcvx1by x ,6l,be 8ro1 a phenotype to cause b8,qlk,e.cyv( xh1n 1i gxrmob8,e g6the appearance of human skin colour.

a. Deduce genotypes for the three j8fz51(ahvymdf,w t5 coat 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 genotype3wbjeql+i+bi h:j jp4 . ylo89) e0ejns 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 i.d a awk+fg8bh.2z;vthe image is mated with a white coat, horned bu.gzfw8vbd;i ha2 a.+ kll.
Construct a Punnett square showing all possible phenotypes of the offspring.

10. The pedigree chart shows ABO blood group al1roy-2v8nxvwdx g1kqa s87+x leles and their genotype for nail-patella syndrome, an i1+xvv8kxwsa1ondq87x 2rg - y nherited 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.