Genetic Techniques

Question 1

What is G banding?

Answer 1

Chromosome digested with trypsin

Stained with Giemsa

Dark and light bands specific to each chromosome

Used to diagnose monosomies, trisomies, translocations, large deletions or insertions

Question 2

What is FISH

Answer 2

Fluorescence in situ hybridization

DNA denatured to ss form

Hybridized with fluorescently labelled probe DNA that binds to a complementary sequence

Region viewed fluorescent microscope

Used to gene mapping or diagnostically to identify a variety of chromosomal abnormalities

Question 3

When are gene loci linked

Answer 3

When their alleles do not show independent segregation during meiosis

Question 4

What is cloning vector?

Answer 4

Transfer of a section of the genome into a single microorganism
Replciated along with the microorganisms own DNA

Restriction enzyme is used to cut and insert the vector DNA

DNA molecules have complementary sticky ends

Vector and insert mixed and incubated with DNA ligase - catalyses formation of phosphodiester bonds between molecules of dsDNA