Table 4.
Examples of genomic changes with possible impact on brain and behaviour
| Drosophila gene(s) | Family | Function | Reference | Novel feature in Apis |
|---|---|---|---|---|
| Vision | ||||
| ninaG | Glucose-methanol-choline oxidoreductases | Involved in biosynthesis of 3-hydroxyretinal | 164–166 | Two putative ninaG-like genes; different chromophore (11-cis-retinal) |
| InR | Receptor protein tyrosine kinase | Insulin receptor, photoreceptor-cell (R- cell) axon guidance | 167 | Gene duplication |
| norpA | Phospholipase C | Phototransduction cascade | For example, 168 | Gene duplication |
| Rh1 (ninaE) to Rh7 | Rhodopsins | Photoreception | For example, 169 | Four visual opsins in honeybee versus seven in fly plus one vertebrate-like non-visual opsin; different chromophore |
| PNR | Photoreceptor-cell-specific nuclear receptor | Differentiation of the visual system | 81, 148 | Three PNRs in honeybee versus two in Drosophila |
| Boss | G-protein-coupled receptor (mGluR-like) | R7 photoreceptor differentiation; ligand of sevenless | 170, 171 | boss missing but sevenless present; nine photoreceptor cells versus eight in Drosophila |
| Thermoregulation | ||||
| TrpA1, pain (painless), pyx (pyrexia) | TRPA subfamily of transient receptor potential channels | Thermal sensing | 172–174 | Missing Drosophila TrpA1, but has two extra TRPA channels (GB14005 and GB16385) |
| Mechanotransduction | ||||
| Nach, rpk, ppk | Degenerins/epithelial sodium channels | Mechanotransduction (for example, touch, hearing, nociception) | 175 | Only 8 degenerins compared with 22 in Drosophila |
| Learning and memory | ||||
| nAcR | Ligand-gated ion channels | Learning and memory processes | 103 | Eleven nAcR subunits in honeybee instead of ten in Drosophila |
| Nmdar | Ligand-gated ion channels | Learning and memory processes | 176, 177 | Three NMDA receptor subtypes in honeybee instead of two in Drosophila |
| Eaat | Excitatory amino acid transporters | Glutamate uptake | 178 | Five EAATs in honeybee, two in Drosophila |
| Circadian rhythms | ||||
| tim1 (timeless) | Timeless/Timeout | Circadian clock: component of a feedback loop, light resetting | 80 | Lost from honeybee |
| dCry (cryptochrome) | DNA photolyase/Cryptochrome | Circadian clock: blue-light photoreceptor | 80, 179 | Lost from honeybee |