1. Red-green colour blindness is caused by an X-linbgzhqb 3/uqc-mq: o .)ked recessive allele. In the pedigree chart below which individq:u-g3z/coqq b b.) hmuals must be carriers of the red-green colour blindness allele?

  2. If the parents in the pedigree chart ab;i, 6wzk9 tp(60 pxw)llhxnleove had a fourth child who was female, what would be the probability 6kwn wpl;0exz)plh lit(,6 x9that she was colour blind?

  3. In Labrador dogs, black coat is d 7s4yt-)n2eay/he q9ci1ll o sominant over chocolate coat. The genotype of a black malh 9-i1q7l y/ lo n)ceea2tss4ye labrador is unknown. How can the genotype of this black Labrador be determined?

  4. Which of the following best defines n 4hpj8re0m+g g4 mfy*the term, “gene”?

  5. Phenylketonuria (PKU) is an inherited human disease caused by a recessi85 m jbsp*kc lulxu,,sv +n19jve autosomal allele in a gene which codes for an enzyme needed to convert phenylalanine to tyrosine. The PKU allele produces a non-functional en+ *8bus n,vc5ju9,j1k lsx mlpzyme.
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 dominant bx1gwxf)o9 r0qyqdj.- b ;n9c.

ii. Deduce the genotype of the ofufz07ooe kthq77xw2 (xyc( 9h fspring.

Iii. Construct a Punnet grid to show the cross betww0 gd.kjt1(,gw h1lhs een two offspring plants of the F1 geneh d,h0 ws(1ltw1 gg.kjration.

Iv. Deduce the phenotypic ratio fo2ct h2mf w7ge sga608kr the offspring of the F1 cross.

7. Amand has a daughter with Padmavathi. Amand is blood group A, Padmavattj,b hx3r.fg(j5i8o2gd;y 9zug w n3r hi is blood group B, and their daughter is blood group O. They are hrg ;xoi j3,zjt2fg.(nug3rh85db9 ywaving a second child, a son.
Deduce the probability that their unborn son will be blood group O. Explain your working.

8. Explain how inheritancl9kmdryv .p0x7y mnfqu3y+(s wf ;5b5 e and environmental factors can interact in a phenotype t(d l3+ x ys7.;9pmqknfuw55 mvf0yybro cause the appearance of human skin colour.

a. Deduce genotypes for the three coat colour phenotypes in these cattle.a18 c)xrg1hbk
Use the symbols $C^W$ for the white coat allele, and $C^R$for red coat allele.

b. Deduce the parental gen4qq9+6wc forlxldh ,zz -0*w notypes 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 coatw+a6)5samii u , horned bull )6+siuma wi5a.
Construct a Punnett square showing all possible phenotypes of the offspring.

10. The pedigree chart shows ABO blood group allele4xw)3*cgu 9 jssok; jyf+hhx 3s and their genotype for nail-patella syndrom 33 wshx+k;xuc9g) f j*4hyjsoe, an inherited 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.