Genetics questions | form four Biology

Colour blindness is a sex linked character controlled by a recessive gene located on the X-chromosome. Only homozygous females suffer from this condition. It is more common to males. What percentage will the males suffering from colour blindness be if a normal male marries a colour blind female?.

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UNSOLVED

If one parent was homozygous tall (TT) and the other homozygous short (tt) what will the
genotype of the offspring be? Illustrate your answer.

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Define the following terms:
(i) Phenotype.
(ii) Recessive.
(iii) Heterozygous

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Study the pedigree below (Figure 4) and then answer the questions that follow.

Open figures indicate normal phenotypes; black figures indicate colour blind individuals.
(i) What is the probable genotype of 1?
(ii) Is the answer to (i) above 100% certam? Explain.
( iii) What is the genotype of 5 and 9?
(iv) Justify your answer in (iii) above.
(v) If 3 marries a normal man, what are the chances that she will have a colour blind son? Illustrate your answer.

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Observe the punnet square below (figure 4).

The possible gene combinations in square number 3 of figure 4 above is

1. bcBc
2. bbCc
3. BbCc
4. Bbcc
5. bbcc

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UNSOLVED