The serotonin transporter is a cell-surface protein that recycles the neurotransmitter ser...

The serotonin transporter is a cell-surface protein that recycles the neurotransmitter serotonin after it has been used to carry a message between nerve cells in the brain. There are two alleles of the serotonin transporter gene:

s and l. Klaus-Peter Lesch and colleagues (1996) found that people with genotypes ls and ss, score slightly, but significantly, higher than people with genotype ll on psychological tests of neuroticism (see Figure)

Figure Distribution of neuroticism score among people with different genotypes of the serotonin transporter gene Redrawn from Lesch et al. (1996).

a. Are these data consistent with the hypothesis that the serotonin transporter gene is a QTL that influences neuroticism? Explain.

b. Is the serotonin transporter gene the gene for neuroticism? Explain.

c. Can you think of another plausible explanation, in which the serotonin transporter gene plays no role at all in neuroticism? Explain.