Question 46 – Inheritance - Edexcel IGCSE Biology Questions

Polydactyly is an inherited condition in humans where affected individuals are born with extra fingers or toes.

This condition is controlled by a gene with two alleles. The dominant allele ( $P$ ) codes for extra digits (polydactyly) and the recessive allele ( $p$ ) codes for the typical number of digits (five per limb).

Two parents who both have polydactyly had a child who has the typical number of digits.

Use a genetic diagram to show:

the genotype of each parent
the gametes they produced
the genotypes of all the possible offspring
the phenotypes of all the possible offspring

State the probability that a second child born to these parents will have the typical number of digits.

Polydactyly is caused by a dominant allele. Explain what is meant by the term dominant allele.

Suggest why the percentage of people with polydactyly in the population is low, even though it is a dominant condition.

Polydactyly is an inherited condition in humans where affected individuals are born with extra fingers or toes.

Two parents who both have polydactyly had a child who has the typical number of digits.

Use a genetic diagram to show:

the genotype of each parent
the gametes they produced
the genotypes of all the possible offspring
the phenotypes of all the possible offspring

State the probability that a second child born to these parents will have the typical number of digits.

Polydactyly is caused by a dominant allele. Explain what is meant by the term dominant allele.

Suggest why the percentage of people with polydactyly in the population is low, even though it is a dominant condition.

Inheritance

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Inheritance

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Inheritance

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Inheritance Questions

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Inheritance Questions