GCSE Biology (AQA)

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Polydactyly

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Inheritance, Variation and Evolution Reproduction

Polydactyly

2:45 Sex Determination and Inherited Disorders
Spec 4.6.1.7
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  • Polydactyly is a genetic condition where animals are born with extra fingers or toes.
  • It is caused by a dominant allele, making it a common condition that runs in families.
  • Individuals with polydactyly have either homozygous dominant or heterozygous genotypes.
  • Only one dominant allele is necessary for a person to exhibit polydactyly.
  • If one parent has two dominant alleles (homozygous dominant), all their offspring will inherit polydactyly.
  • If one parent is heterozygous for polydactyly and the other is homozygous recessive, there is a 50% chance their offspring will inherit polydactyly.
  • If both parents are heterozygous, there is a 75% chance their offspring will inherit polydactyly.
  • The extra fingers or toes may sometimes be removed if they cause problems.
  • Understanding and predicting the inheritance of polydactyly involves using Punnett squares to determine the probability of offspring inheriting the condition based on parental genotypes.

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