Practise describing selective breeding in animals, using cattle, fish and dogs to select parents, choose offspring and repeat over generations.
Reflexes are responses that protect the body and involve the central nervous system (CNS).
The photograph shows a breed of dog called a border collie.
Some border collies have a genetic condition called sensory neuropathy.
Border collies with sensory neuropathy may be injured as their reflexes do not work well.
Sensory neuropathy is caused by a recessive allele, n . The dominant allele for not having sensory neuropathy is N .
The diagram shows a family pedigree for some border collies.
Dog breeders use selective breeding to try to remove harmful alleles from dog breeds.
Explain how selective breeding could be used to remove the allele for sensory neuropathy from a population of border collies.