Children
growing up in harsh environments and circumstances can age them. Children in
severely disadvantaged conditions can experience drastic chromosome ageing (New
Scientist, April 7, 2014).
Penn
State University in University Park, in the United States, conducted tests on
forty boys, all 9 years of age, half of whom grew up in extremely 'harsh'
backgrounds and half of whom grew up in 'privileged' homes, to see the affect on
their chromosomes. The researchers were particularly looking at telomeres – the
caps on the ends of chromosomes that shrink each time cells divide. Telomeres
protect chromosomes from damage.
The
researchers noted that the telomeres could shorten under severe conditions.
Some telomeres were as short as those from a person decades older.
The
boys whose mothers who had changed partners more than once by the time their
son was 9 years old had telomeres 40% shorter than the boys whose mothers had
not changed relationships. Harsh parenting and younger mothers also resulted in
shorter telomeres in their sons.
The
boys whose mothers had gone to college had 35% longer telomeres on average than
the boys whose mothers had not gone to college.
The
researchers also noted that particular genetic mutations seemed to make
children more sensitive to their environment. Serotonin and dopamine were more
prevalent in the long telomeres of children from backgrounds that were not
harsh. Serotonin is a neurotransmitter – a chemical substance – that transmits
nerve impulses across synapses. Higher levels of serotonin help relieve
symptoms of depression. Dopamine is a neurotransmitter that helps control the
brain’s reward and pleasure centers, and regulates movement and emotional
responses. People with low dopamine activity may be more prone to addiction.
Daniel
Notterman of Penn State University has cautioned that the link between shorter
telomeres and health outcomes is not yet fully established. However, the
research has shown “profound change” in children’s telomeres by the time they
are 9 years old.
Due
to the small sample size, the researchers plan to extend the study to include
1,000 children and follow them to the age of 15 years of age to determine whether
there is a significant link between harsh living conditions and children’s
health. Given that some living conditions are not easily prevented or changed,
another step could be to determine how to mitigate any negative affects on
children’s health as they grow.
http://www.newscientist.com/article/dn25370-harsh-world-makes-kids-chromosomes-look-middleaged.html#.U0RJcj_NvIU
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