what are sequence homology searches?
> on which levels?
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
how to make knock out mice?
- use embryonic stem (ES) cells
- switch of your gene
- inject your ES cell into mouse embryo
> chimera mouse with mixed cells
- mate chimeric mice
- some offspring will be homozygote of your cell!
tada
what are the 3 functional levels gene products can be analyzed on?
- biochemical level: e.g. gene product is calcium-binding protein
- cellular levels: e.g. protein is in ucleus and required for DNA repair
- organism level: when/when is the gene expressed in the organism
on which 2 levels can sequence homology searches be conducted?
> which one preferred?
- transcriptional
- proteomics
> proteomics preferred, more confident because more conserved
what are orthologs?
what are paralogs?
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
what are two broad ways to study gene function?
- forward genetic (classical)
> phenotype -> genotype
- reverse genetics
> genotype -> phenotype
