6.1.7 Inherited Disorders

Polydactyly: having extra fingers or toes

• Caused by a dominant allele

Cystic fibrosis: this is a disorder of the cell membranes, resulting in thick mucus in the airways and pancreas

• Caused by a recessive allele
• Both parents need to either be carriers (have one of the recessive alleles) or one must have CF themselves and the other is a carrier.

Embryonic screening allows scientists to observe whether the child will have a genetic condition or not.

• If the embryo is developed in the lab, cells can be taken from it and analysed
• DNA from embryos in the womb can also be extracted There are many economic, social and ethical issues surrounding embryonic screening.

Arguments for embryonic screening	Arguments against embryonic screening
Reduces the number of people suffering (ethical).	Could encourage people to pick characteristics • creating designer babies (ethical).
Treating disorders is very expensive (economic).	It is expensive to carry out screening (economic).
There are many regulations in place to stop it getting out of hand (social).	May promote prejudice as it suggests that those with genetic disorders will not live a full life or are unwanted (social).
	Decisions about terminating a pregnancy have to be made (social).
	The procedure can lead to a miscarriage (social).