1. Red-green colour blindness is caused by an X-linked recessive:hkn.+cfj x ;-bs7rf/ *wxovr allele. In the pedigree chart below which individuals must be carriers o*x/cs r+nhf; vwk-:. rbf7joxf the red-green colour blindness allele?

  2. If the parents in ,a0j14hl3nvc h6mgsl the pedigree chart above had a fourth child who was female, what would be the probabillvjgs c,h16hnal03m 4ity that she was colour blind?

  3. In Labrador dogs, blk). pxtg1 u4nz.yr 7voack coat is dominant over chocolate coat. The genotype of a black male labrador is unknown. How can the genotype of t.pyvg 4t )7onuk. r1zxhis black Labrador be determined?

  4. Which of the folloqpvp2 2 +;1+idlp vdrn5h9x ;lvjp fr8wing best defines the term, “gene”?

  5. Phenylketonuria (PKU) is an inherited human dviezl;rljq14n. 0 9r:+gvmp ;ggtq)oisease caused by a recessive autosomal allele in a gene which codes for an enzyme needed to convert phoelgr: 1)0tliv m+gqq4rn;p j. g;zv9enylalanine 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 alljc7cp0 ,jpedc,4o xj)eles, yellow or green, is dominant.

ii. Deduce the genotz94ve; yejoo ()3 n 1ck7djofzype of the offspring.

Iii. Construct a Punnet grid to show the cross between twor1xt :uv 4y4tx offspring plants of the F1 generationr x14:vt4yx ut.

Iv. Deduce the phenotypic ratio for the offspring of the F1 zbnp bq )idf8e /lxcx*:s( 1yo*tn.3vq5(ebo cross.

7. Amand has a daughter with Padmavath b7ldba(x zimpm ml9 2zfhy+)0m8s 5k-i. Amand is blood group A, Padmavathi is blood group B, and their daughter is blood group O. They are having a secondm+l m0-mza 8pi2 mbz7ksylxbf)dh59( child, a son.
Deduce the probability that their unborn son will be blood group O. Explain your working.

8. Explain how inheritance and environmental factorsa2yur osg9wf /( 6t r49c4rqikgclf/ 2 can interact in a phenotype to cause the appearance of human skin col(9fr9ri l 2w4rfgcqat624/ok/ gucysour.

a. Deduce genotypes for ty98,hgw 0x+x o*gxyq1o u:s z(:xu9 t8wfdebqhe 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 zzz(*baw*b,a 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 coat, 1k :l+e5p2dnd yi,kkqhorned b51:p2de lk+kyi,k dqn ull.
Construct a Punnett square showing all possible phenotypes of the offspring.

10. The pedigree chart shows ABO blood group /a mx u x:xl *l9y+r6crejse,.alleles and their genotype for nail-patella syndrome, an inherited condition. The individuals 1, 3, and 4 in+ aul6,/:cej*x r9 x.ms yerlx row III are recombinants. Image by D.B. Pylypiv.

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