1. Red-green colour blindness is caused bhsq; u8y9)xzvy an X-linked recessive allele. In the pedigree chart below which individuals must be carriers of the red-green colour blindness alle 8;uzvh9 sqxy)le?

  2. If the parents in dhmi, g1m8dlj:b/eyqq 690usthe pedigree chart above had a fourth child who was female, what would be the probability that she was colour blinuj6deg8h9s ,qbdmq0: /imly1d?

  3. In Labrador dogs, b)f76hr-jyew a lack coat is dominant over chocolate coat. The genotype of a black male labrador is unkna7eh ry)6w jf-own. How can the genotype of this black Labrador be determined?

  4. Which of the following ben3st0 7h 6krsd;ogui 2st defines the term, “gene”?

  5. Phenylketonuria (PKU) is an inherited human disease caused by a recessiv x3)p hp;/t nb08yogkue autosomal allele in a gene whinpgxp)tuh/yo30 ;k 8 bch codes for 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 ti+rn.-cd q +lalleles, yellow or green, is dominant.

ii. Deduce the genotype/irl:qf q5oz 1 of the offspring.

Iii. Construct a Punnet grid to show the cla4:v3tt )+ yaq: igtcross between two offspring plants of theay)g a:tlt t4+3 civ:q F1 generation.

Iv. Deduce the phenotypic ratio for the offsprin5unbu ic:p93qip(jw 3g of the F1 cross.

7. Amand has a daughter with Padmavathi. Amand is bz:j(2h3 rbm wij3v xc ak0:f(elood group A, Padmavathi is blood group B, (ja2mf 3:3x rzebj(k:wv0ich 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 inheritance and environmental factors can interamt0uxzu+f . :htwl5j:t/ oi6j ct in a phenotype to cause the appearance of humaz/ wm:t uf0x.itjt6u5 +jho l:n skin colour.

a. Deduce genotypes for u58lze6fd5 a,7y sibfthe three 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 genotypes of the cow in ts7 myt y)j9o l-c5sov)bcn8:vhe 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 e4fq 5x:jab /2 fhgvmfi 0eh.3a white coat, horned beq2.hbf je hfxa3v5f0g4m /i:ull.
Construct a Punnett square showing all possible phenotypes of the offspring.

10. The pedigree chart shows ABO blood groupxpd w;vi a*fm (yv6)1p alleles and their genotype for nail-patella syndrome, an inhvd xpfy*;iw1v pm(a )6erited 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.