Albinism is an inherited condition in humans that results in a lack of melanin pigment in the skin, hair, and eyes. It is caused by a recessive allele. This means that only individuals with the homozygous recessive genotype have albinism.
What is meant by the term heterozygous?
State the two possible genotypes of an individual who does not have albinism. Use the symbols AAA for the dominant allele and aaa for the recessive allele.
A homozygous dominant mother and a homozygous recessive father have two children. State the genotypes of the parents and their children.
What is the probability that the children have albinism?
People from different countries were tested to see if they have albinism. The table below shows the number of people tested in each country and the percentage who have albinism.
| Country | Number of people tested | Percentage with albinism (%) |
|---|---|---|
| J | 240 | 3 |
| K | 380 | 5 |
| L | 150 | 14 |
| M | 30 | 60 |
| N | 15 | 100 |
The population size of country K is 120 million. Calculate the number of people in this country likely to have albinism. Show your working.
Suggest a reason why the value of 100% for country N may not be representative of the actual population percentage possessing albinism in that country.
