Chapter 12

Question 1

what are sequence homology searches?

> on which levels?

Answer 1

when finding a new gene

> function of identified gene may be unknown

> but it could be evolutionarily relatd to another gene with a defined function

> sequence comparisons on either DNA level or protein level

Question 2

how to make knock out mice?

Answer 2

1. use embryonic stem (ES) cells
2. switch of your gene
3. inject your ES cell into mouse embryo

> chimera mouse with mixed cells

4. mate chimeric mice
5. some offspring will be homozygote of your cell!

tada

Question 3

what are the 3 functional levels gene products can be analyzed on?

Answer 3

1. biochemical level: e.g. gene product is calcium-binding protein
2. cellular levels: e.g. protein is in ucleus and required for DNA repair
3. organism level: when/when is the gene expressed in the organism

Question 4

on which 2 levels can sequence homology searches be conducted?

> which one preferred?

Answer 4

1. transcriptional
2. proteomics

> proteomics preferred, more confident because more conserved

Question 5

what are orthologs?

what are paralogs?

Answer 5

orthologs: assumed to perform identical or closely related functions
paralogs: functional predictions may be reliable on biochemical level, but cellular/organism level functions may be different

Question 6

what are two broad ways to study gene function?

Answer 6

1. forward genetic (classical)

> phenotype -> genotype

2. reverse genetics

> genotype -> phenotype