Inheritance: Cystic Fibrosis and Polydactyly

Question 1

What is cystic fibrosis?

Answer 1

• Disorder of cell membranes.
• Controlled by a single gene, has 2 Alleles.
• Allele for normal cell membrane function: Dominant. (C).
• Allele for defective cell membrane function: Recessive (c).
• so person has to have 2 copies defective cell membrane Alleles.
• Inherit a defective Allele from both parents.

Question 1

What is cystic fibrosis?

Answer 1

• Disorder of cell membranes.
• Controlled by a single gene, has 2 Alleles.
• Allele for normal cell membrane function: Dominant. (C).
• Allele for defective cell membrane function: Recessive (c).
• so person has to have 2 copies defective cell membrane Alleles.
• Inherit a defective Allele from both parents.

Question 2

What is a carrier for Cystic Fibrosis?

Answer 2

• One Defective Allele and Normal Allele does not have Cystic Fibrosis.
• Carrier of the CF Allele.

Question 3

What is Polydactyly?

Answer 3

• Extra fingers or toes.
• Caused by a dominant Allele.
• ## Cannot be a carrier.

Question 4

How can we reduce the chances of inherited diseases?

Answer 4

• Embryo Screening: Embryo’s are tested to see if Alleles of the genetic disorders are present.
• Embryo’s that do not have the defective Alleles are implanted into the women (Develop healthy).

Question 5

What are the problems of embryo screening?

Answer 5

• Expensive. Some people think money should be spent elsewhere in the Health Service.
• Large number of Embryo’s are created but only a small number are implanted.
• Some healthy embryo’s are destroyed and some people think it’s unethical.

Question 6

What could Embryo screening be like in the future?

Answer 6

• May be able to screen embryo’s to produce offspring with desirable characteristics.
• E.g: Taller or more intelligent.
• Many people find this unethical.

Question 7

What is gene therapy?

Answer 7

• Correcting fault Alleles and use them to treat inherited disorders.
• Experimental.