Functional genomics investigating gene function

Question 1

How do we find out the function of a gene?

Answer 1

the information that we have from genome sequencing projects means that we can identify many new genes from any given organism

Question 2

direction of forward genetics

Answer 2

starts witha phenotype -> discovers the gene

Question 3

direction of reverse genetics

Answer 3

starts with a gene, discovers the phenotype.

Question 4

reverse genetics makes use of …

Answer 4

… genome sequence to discover functions of genes

Question 5

define phenotype

Answer 5

the set of observable characteristics resulting from the interaction of its genotype with the environment,

Question 6

examples of phenotype

Answer 6

example the characteristics of a T cells, what it does in an immune response – activates / suppresses to respond to the bug / virus etc, so could be a gene that is switched on the make a pro-inflammatory mediator.

Question 7

what is alternative reverse genetics?

Answer 7

Alternatively we can do reverse genetics where we start with the gene so we overexpress or mutate the gene and then examine the change to the phenotype - so we start with the gene, rather than the phenotype e.e Give example of mutations in genes related to weight / appetite – mutagenesis of these can lead to morbid obesity in mice

Question 8

what is mutagenesis?

Answer 8

the production of genetic mutations – to see how this effects the phenotype of animals for example.

Question 9

slide 4

Question 10

slide 7

Question 11

most forward genetic screens now make use of …

Answer 11

…tansposable elements

Question 12

what are transposable elements?

Answer 12

these are DNA molecules that are able to integrate into a genome at random

Question 13

if we know the sequence of these transposable elements then we can identify …

Answer 13

… where they have been inserted

can be done using pcr, southern blotting/libraries, using transposable element derived probes.

Question 14

we can use saturation mutagenesis to …

Answer 14

… build a population with lots of insertions – then identify those that have a phenotype that we are interested in investigating – proves importance of the gene.

Question 15

slide 9

Question 16

most organisms are able to undergo…

Answer 16

homologous rembination

Question 17

where is this important?

Answer 17

important in meiosis and in dna repair where the double strand is broken.

Question 18

by introducing a recombinant DNA molecule into a cell of a eukaryote we can …

Answer 18

… replace the gene we are targeting.