Short slices of DNA in human brain tissue can help understand human cognitive functions and risk-proneness for Alzheimer’s and autism, says a new study published in the journal PLoS Biology. The Mount Sinai School of Medicine researchers have found that many sequences with epigenetic characteristics, until recently considered to be “junk DNA”, can present leads on how the human brain has evolved, and a starting point for studying neurological diseases.
There are nearly 40 million positions in the human genome with DNA sequences different than those in non-human primates, making the task of learning which are important and which are not a challenge for scientists.
Rather than comparing these sequences strand by strand, the team wanted to identify the crucial differences between the two genomes by looking more broadly at the chromatin that packages the DNA and controls its expression. They found regions in the human genome which show a markedly different chromatin structure in neurons in the prefrontal cortex as compared to those in monkeys or guerillas.