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A2 biology unit 4

please can someone help me with this doubt
How does the 5-HTT gene relating to depression work?
In the A2 student biology book it says " The gene codes for a reuptake protein that enables serotonin to be taken back into the presynaptic membrane after releases into the synapse......... The long form of this gene means more of it is produced. " ...." Those homozygous for the long form have a very low risk of depression"
How? If long form has increased reuptake proteins then won't the serotonin levels in the synaptic cleft decrease? And won't this lead to increased chance of depression. Please explain.
It's be highly appreciated.

Reply 1

hope1817

I believe from what i have read, I may be wrong, but that the reuptake proteins help to recycle the seretonin. This, along with the long gene making more of the seretonin-it decreases chances of depression.
So in the synaptic cleft they will decrease after the reuptake protein has increased. But this is only temporary as the gene also produces more. It just allows the reuptake to occur faster and hence with the greater production the whole action potential can be generated faster and hence more APs are created in Post SM/more nerve impulses are passed along.

hope this is right and answers your question :smile: