geNorNics Biochemistry: Receptor

Genome Content: C1 C2

Gene Sequence

01 00 ## 00 so sm mr l1 l2 l3 cr tt no gg op

01 - gene type: biochemistry
00 - gene subtype: receptor
## - gene subtype number
00 - unknown
so - switch on: embryo
sm - sex-dependence/mutability
mr - mutation rate (C2 ONLY)
l# - locus of attachment ID
cr - chemical received
tt - threshold
no - nominal
gg - gain
op - output

Notes

sm - sex dependence/mutability

See the Header page for a complete discussion of this byte.

l# - locus ID

The locus of attachment of the chemo-receptor object. This three-character Locus ID represents 'organ,' 'tissue,' and 'site.'
See the LOA - Receptors (C1 or C2 ) for the complete listing.

cr - chemical received

The chemical that binds to the receptor and triggers its 'firing' -- i.e. the chemical monitored by the receptor.
See the ChemList (C1 or C2) for a listing of all the chemicals in Creatures.

tt - threshold

The threshold is the level of chemical that must be present before the neuron bearing the bound receptor (the 'locus' above) will 'fire' (be activated).

According to the Creatures Developers Resource, the following formulas are used for calculating the new value of the locus when the amount of chemical exceeds the threshold:

    Digital: new value = nominal + (gain * R)
     Analog: new value = nominal + (((amount - threshold) * gain/255) * R)

        where R is either 1 or -1 (see op - output below).

no - nominal

The 'nominal' of the receptor -- the amount to stimulate the locus if the chemical does not exceed the threshold. See the formulae above.

gg - gain

The 'gain' of the receptor -- the amount to stimulate the locus if the chemical does exceed the threshold. See the formulae above.

op - output

There are two check boxes on the Receptor gene editor:

Output REDUCES with increased stimulation
Digital (o/p = nominal +/- gain if sig > threshold)

The first option determines whether the 'firing' of the neuron results in an increase in the value for the locus or in a decrease (listed as R in the formulae above).

The second option sets a receptor as Digital -- when unchecked, receptors are Analog. This choice determines which formula is used to calculate the new value for the receptor.

All the observed values in the byte can be explained with the last two bits:

Bit # 7 6 5 4 3 2 1 0  00 - 0 0 0 0 0 0 0 0  01 - 0 0 0 0 0 0 0 1  02 - 0 0 0 0 0 0 1 0  03 - 0 0 0 0 0 0 1 1

Bit 0 - Reduces Bit 1 - Digital

In summary:

00 - 
01 - Reduces
02 -          Digital
03 - Reduces  Digital