Genetics questions | form six Biology

Albinism is an autosomal recessive genetic defect. The pedegree below shows the inheritance of the defect in a certain family.

1. i) State the number of all individuals who are definitely heterozygous for the gene controlling the defect 

          ii)What is the probabilty that individual 6 is heterozygous?

2. i) How is inheritance of Albinism similar and yet different from that of haemophilia?

          ii) Why are men more likely to be haemophiliacs than women?

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UNSOLVED

Distinguish between sex determination and sex linkage

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Define the following terms

1. Chromosomal mutation
2. Co-dominance
3. Polygenic inheritance

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UNSOLVED

Albinism in human beings is caused by a recessive gene which is transmitted in Mendelian fashion.A couple which is phenotypically normal for skin pigmentation has four children. The first three have normal skin and the fourth is an albino.

1. What is the genotype of the parents?
2. What is the probability that the fifth child will be an albino?
3. One of the first three children marries a normal skinned woman. What predictions can you make regarding the skin of their first child ?
4. The albino child marries a normal skinned widow who had an albino child in her first marriage. What is the probabilty of this couple to produce a normal skinned child?

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UNSOLVED

In man, the ability to roll the tongue into almost a complete cycle is determined by a dominant gene, while its recessive allele fails to produce this ability. A man and his wife and can both roll their tongues. They are suprised to find that their daughter cannot. Explain this by showing the genotypes of all three persons.

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UNSOLVED