Growing up in a stressful social environment leaves lasting marks on young chromosomes, a study of African American boys has revealed. Telomeres, repetitive DNA sequences that protect the ends of chromosomes from fraying over time, are shorter in children from poor and unstable homes than in children from more nurturing families.
he link between stressful home environments and telomere length is moderated by genetic variants in pathways that process two chemical transmitters in the brain, serotonin and dopamine, the study found. Previous studies have correlated variants in some of the genes studied, such as TPH2, with depression, bipolar disorder and other mental-health issues. Variants of another gene, 5-HTT, reduce the amount of the protein that recycles serotonin in nerve synapses. Some alleles of these genes are thought to increase the sensitivity of carriers to external risks.
In the latest study, the researchers found that the 'sensitizing' variants of these genes protected telomeres in children from nurturing environments, and caused greater telomere damage in children from disadvantaged homes. Those who lacked these alleles had little difference in their telomeres, regardless of living conditions.
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Category(s):Child Development, Stress Management
Source material from Scientific American
