Psychological Disorders Questions

Geneticists investigating a gene that controls a serotonin transporter protein that controls serotonin reuptake analyzed the 5-HTT genes of 847 people, determining two types: a ‘short’ and a ‘long’ allele. Each participant had been given a questionnaire which asked the individual to list any highly stressful life events experienced between the ages of 21 and 25. The figure shows the results for individuals with two long, two short, and one long gene and one short gene. What relationship did the data show between genetics and major depression episodes for individuals possessing two short alleles of the 5-HTT gene?