Rights And Wrongs Of Genetic Manipulation

Question 1

How can animals be engineered to prevent rejection by inserting genes into the animals DNA?

Answer 1

Genes from human cell surface proteins are injected into a newly fertilised animal embryo

    - the genes integrate into the animals DNA 
    - the animal then produces human cell surface proteins
    - reduces the risk of transplant rejection

Question 2

What are the ethical issues surrounding the use of genetic engineering?

Answer 2

• using antibiotic resistance genes as marker genes may increase the number of antibiotic resistant, pathogenic microorganisms in our environment
• reduction of genetic diversity in plants if only certain GM crops are grown
• engineering animals by xenotransplantation may cause suffering
• the spread of genes that are resistant to pests or herbicides from crops to weeds making ‘super weeds’
• humans could be genetically engineered to be more intelligent or look a certain way, create a genetic underclass (currently illegal)

Question 3

What is xenotransplantation?

Answer 3

• it is the transfer of cells, tissues or organs from one species to another
• chance of rejection (immune system of the recipient recognises proteins on the surface of the transplanted cells as foreign and starts an immune response against them)

Question 4

How can animals be engineered to prevent rejection by knocking out genes?

Answer 4

• animal genes involved in making cell surface proteins are removed or inactivated in the nucleus of an animal cell
• the nucleus is then transferred into an unfertilised animal egg cell (nuclear transfer)
• the egg cell is then stimulated to divide into an embryo and the animals cell created doesn’t produce animal cell surface proteins which reduces the risk of transplant rejection