Draft #2, week 10, notes on olfactory sensory neurons research paper

How do individual OSNs that express a single type of odorant receptor (OR) converge onto the same glomerulus in the OB
- odor info is detected by ~1000 different olfactory epithelial ORs and this is topographically represented by the ~1000 pairs of glomeruli in each OB
HOW is this target precision achieved??
Mouse
- ~1000 functional OR genes in the mouse, comprising 4% of all protein-coding genes in the genome, are dedicated to olfaction
- largest multigene family in mouse
- OR genes are clustered at ~50 different loci that are scattered among most of the chromosomes
- “one neuron – one receptor” rule = one allele (paternal or paternal) per neuron
- the OR gene choise in mouse appears to be stoachastic (one allele)
HOW is it that a single OR gene is chosen and activated from a repertoire of 2000(3000)?
What kind of mechanism would be possible to maintain the expression of only a single OR gene in each OSN??, these are the possibilities:
1.) DNA recombination
2.) gene conversion
3.) regulation by a locus control region (LCR)