1. Red-green colour blindness is caused by anp uc4krj 3; xi;a),tuz X-linked recessive allele. In the pedigree chart below which individuals must be carriers of the red-green colour blindness allele? ,3i 4raptuxucz;kj ; )

  2. If the parents in the pedigree q:4 ebm :f4uywchart above had a fourth child who was female, mebf :: yuqw44what would be the probability that she was colour blind?

  3. In Labrador dogs, black coat is dominant over chocolate coat. The geutv.oy3 p 5hu*p8ej,snotype of a black male labrador is unknown. Hto,uh*.y e8jv u5pp3 sow can the genotype of this black Labrador be determined?

  4. Which of the following best definpo9-.kytwb23kl0h rx/ mv.fyes the term, “gene”?

  5. Phenylketonuria (PKU) is an inherited human hl/,,8ouby3ui q je4q disease caused by a recessive autosomal allele in a gene which codes for an enzyme needed to convert phenylalanine to tyrosine. The PKU allele produces a non-functional enzyme. eob48/iqhqju,, uy3l
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, yel;a y.pijrr-8blow or green, is dominant.

ii. Deduce the genotype of the offsp , n5a)fz2mbrlring.

Iii. Construct a Punnet grid to show the cross between two .x bv8cle+m*) v-wt rpoffspring plants of the F1 genermvl-ctweb rp8).xv*+ ation.

Iv. Deduce the phenotypic ratio fori f;xgf h .9g80y57hocifr7rs the offspring of the F1 cross.

7. Amand has a daughter with Pa1yem1f pmay2 wx o*i)8dmavathi. Amand is blood group A, Padmavathi is blood group B, and their daughter is blood group O. They are having a p)1 emxfyy*wom21 i8asecond 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 interact in a ol +g8lrfxj,3p qql8: phenotype to cause the appearance of human sjqg3l8 +pq o:x,lrfl8kin colour.

a. Deduce genotypes foruciv --zpusfa5ul6q qz ;/ 0b0 the 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 thqm6ru **-k/jjsqw vbb 7*h .pse image.
Use P for the allele for polled and p for the allele for horns.

c. The roan colour, polled cow in the hzkr/ w*. g ;ee5kys/limage is mated with a white coat, horned burw/ * hez;.y5le/sgkkll.
Construct a Punnett square showing all possible phenotypes of the offspring.

10. The pedigree chart shows AB:bj yx1o4y--u:c d r3wohsg.gO blood group alleles and their genotype for nail-patella syndro go 31j.sygdb:rwu- :h-cy x4ome, 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.