A herd of goats has been selectively bred for high milk yield. One family line in the herd contains a recessive allele that causes an inherited nerve disorder.
The farmer stops choosing both parents from this family line. Instead, one parent is chosen from a different, unrelated family line.
Explain how this change could reduce the proportion of kids born with the nerve disorder.
Before the next breeding season, the farmer also brings goats into the herd from several unrelated herds.
Explain how this could reduce the number of goats lost if a new disease affects the herd in the future.
80 exam-style questions on AQA GCSE Biology 6.2 Variation and evolution, covering 6.2.1 Variation, 6.2.2 Evolution, 6.2.3 Selective breeding, 6.2.4 Genetic engineering, and 6.2.5 Cloning. Each one has a worked solution and a mark scheme showing where the marks go.