You are viewing a free preview of this lesson.
Subscribe to unlock all 10 lessons in this course and every other course on LearningBro.
This lesson covers the genetic basis of inherited disorders — conditions caused by faulty alleles that are passed from parents to their children. For AQA GCSE Biology, you need to know about polydactyly (a dominant disorder) and cystic fibrosis (a recessive disorder). You also need to understand genetic screening and the ethical debates surrounding it.
Inherited disorders (also called genetic disorders) are caused by mutations in genes that are passed from parent to offspring. They are not caused by pathogens and cannot be "caught" — they are inherited through the alleles received from parents.
Some inherited disorders are caused by dominant alleles, meaning only one copy of the faulty allele is needed to cause the condition. Others are caused by recessive alleles, meaning two copies of the faulty allele are needed.
| Inheritance pattern | Number of faulty alleles needed | Example |
|---|---|---|
| Dominant disorder | One copy (heterozygous or homozygous) | Polydactyly |
| Recessive disorder | Two copies (homozygous recessive only) | Cystic fibrosis |
Subscribe to continue reading
Get full access to this lesson and all 10 lessons in this course.