1. Red-green colour blindness is caused by an X-linked recessive allel 5.uns esiyi d8 -di8ux1t xo83uy()zqe. In the pedigree chart below which individuals mue3 xyd8(oiys zi815t- iu8)uxd sn.uqst be carriers of the red-green colour blindness allele?

  2. If the parents in the pedigree chart above had a fourth child whoq bkxs8/ v )ip1/8u)y hj ,9yejcoow(p was female, what would be the ewyouqvo pk, 1 hcsb8 (8xj )ypij)/9/probability that she was colour blind?

  3. In Labrador dogs, black coat is dominant over chocolate coat. The genotype of6-ahici *a yhs27hel5 cs la hy7*eai6h52-ih a black male labrador is unknown. How can the genotype of this black Labrador be determined?

  4. Which of the following best defines the termu hdgd.3lzt,l6x/9aq , “gene”?

  5. Phenylketonuria (PKU) is an inheritido*tu 6.,o )qww+xe9gmj p1bed human disease caused by a recessive autosomal allele in a gene which codes for an enzyme needed to convert phe9ub,d.oxgpi+ w oqm1)*6wt ejnylalanine 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 lcbi:0,n3v8wfp u; mg the alleles, yellow or green, is dominant.

ii. Deduce the genotyyis/k6 efu,l1(ey yjr2 hd/0e pe of the offspring.

Iii. Construct a Punnet grid to show6ng(n.;d- ; ik(6y zvrhdkhko the cross between two offspring plants of the F1 gehrogn6zd kv.(6-;yk ;h kid(nneration.

Iv. Deduce the phenotypic ratio for the offsprfz lzc:h0 oi5fls(n3y d/tw94ing of the F1 cross.

7. Amand has a daughter with Padmavathi. Amandwn jr)/ +i0fmyx0oby9 is blood group A, Padmavathi is blood group B, and their daughter is blood group O. They are having a sec rymwn/+)0 x9jboi y0fond child, a son.
Deduce the probability that their unborn son will be blood group O. Explain your working.

8. Explain how inheritance and enviro-uxs:8uywi( 0 budk/2 r +k ;n;hxmebsnmental factors can interact in a phenotype to cause the appearance of human skin /w ; 8s smxbn xb d+h(:u2kk;u0yrei-ucolour.

a. Deduce genotypes for the three coat colour phenotypes 5;o,4 mpabjho 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 ofzlb uw5vv12chj 6n0axb5)v+) wj: 7bqy5dynb the cow in the image.
Use P for the allele for polled and p for the allele for horns.

c. The roan colour, polled.tt sa;)6tdc42td4qz ,sy uea cow in the image is mated with a white coat, horned bz4sty cae,s2dt. ; t)d46aqt uull.
Construct a Punnett square showing all possible phenotypes of the offspring.

10. The pedigree chart shows ABO blood group alleles and their genotype for nail 9pc. ei hs70l+zvudn+wor5.b7.emcn -patella syndrome, an inherited con .wec5 b+o9pld.i7u . nerv s07ch+mnzdition. 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.