Biochem 83

Question 1

What occurs in florescent in situ hybridization?

Answer 1

Florescent DNA or RNA probes bind to a specific gene site of interest on chromosomes

Question 2

What is florescent in situ hybridization used for?

Answer 2

Visualization to see if a gene is present or direct visualization of anomalies such as microdeletions

Question 3

Describe the results of florescent in situ hybridization

Answer 3

Florescent = gene present
Non-florescent = gene absent

Question 4

Describe the steps of cloning (5)

Answer 4

1) Isolate eukaryotic mRNA
2) expose mRNA to reverse transcriptase to produce cDNA (lacks introns)
3) Inserts cDNA fragments into bacterial plasmids containing antibiotic resistance genes
4) Transform recombinant plasmid into bacteria
5) Surviving bacteria on antibiotic medium produce cDNA

Question 5

How are insertions or deletions of genes in mice targeted?

Answer 5

homologous recombination

Question 6

What is the Cre-lox system?

Answer 6

Can inducibly manipulate genes at specific developmental points

Question 7

How does interference RNA work?

Answer 7

1) dsRNA is synthesized that is complementary to the mRNA sequence of interest.
2) transfected into human cells, dsRNA seperates and promotes degradation of target mRNA, “knocking down” gene expression.

Question 8

Karyotyping is used to diagnose what?

Answer 8

Chromosomal abnormalities such as:

1) Autosomal trisomies
2) sex chromosome disorders