Gene Therapy

Question 1

What is gene therapy?

Answer 1

Changing faulty alleles that cause genetic disease

• can be caused by dominant or recessive alleles

Question 2

What is gene therapy for dominant alleles?

Answer 2

e.g. Hunting disease - Hh - heterozygous

• The sufferer will be heterozygous
• They will have the working allele and non-function allele
• You have to find to stop the dominanet allele
• Use a vector and add a dna fragment into dominant allele
• dominant allele wont be transcribed
• recessive allele is expressed

Question 3

What is gene therapy for recessive alleles?

Answer 3

e.g. cystic fibrosis - ff - homozygous recessive

• sufferer will be homozygous
• we can use a vector and add the functional allele to the DNA
• dominant allele will be expressed

Question 4

What are the two types of gene therapy?

Answer 4

• germ line gene therapy - when you change the alleles of the gametes - all future
  offspring will inherit - illegal in humans
• somatic gene therapy - changing the alleles of body cells - non-sex cells - offspring dont inherit
  changes

Question 5

What are some problems with gene therapy?

Answer 5

• alleles will be inserted into the wrong locus - they wont be translated or expressed properly
• could silence wrong gene by mistake e.g. tumour supressor gene (slows down the rate of cell division) - if you break this,
  then cells will grow faster and can cause cancer
• gene can be overexpressed
• use of gene therapy could be used for non-medicinal uses