Outline what is meant by the term genetic markers.

Outline two uses of genetic markers.

Evaluate the use of viral vectors in gene therapy.

Outline the use of microarrays to test for genetic disease.

A gene/DNA sequence «with a known location on chromosome» used for identification

a. to identify species/pathogenic organisms
OR
successful uptake of DNA in genetically modified organisms/GMOs 

b. to detect disease due to variation in DNA «substitution/deletion» 

c. to determine risk of developing certain disorders 

d. to confer resistance to antibiotic/agent that would normally kill it 

e. to make cells containing gene look different
OR
green fluorescent tag makes cells visible under UV light

a. gene therapy trials have used viruses to deliver un-mutated copies of genes to the «somatic» cells of the patient's body 

b. examples of the use of viral vectors  eg gene therapy may provide a way to cure genetic disorders, such as severe combined immunodeficiency

c. one of the main problems is immune response to viruses / may cause toxicity/disease 

d. some viral vectors insert their genomes at a random location on one of the host chromosomes «which can disturb the function of cellular gene» / enter wrong cells «if targeting tumour» / could lead to cancer

a. analyze tissue/blood sample for DNA sequence 

b. each spot «on microarray» has small quantity of specific DNA sequence/probe 

c. reverse transcriptase used to make cDNA 

d. fluorescent dye linked to cDNA 

e. «cDNA» binds to/hybridizes with probes that have complementary base sequences 

f. fluorescence/different colours shows probes have hybridized / which sequences were in the tissue sample

Allow specific examples of genetic diseases.