The “switching on” or expression of specific genes in the human genome is what makes each human tissue and each human being unique. A new study by researchers at the Johns Hopkins Bloomberg School of Public Health, the Lieber Institute for Brain Development, the National Institute of Mental Health, and collaborating institutions has found that many gene expression changes that occur during fetal development are reversed immediately after birth. Reversals of fetal expression changes are also seen again much later in life during normal aging of the brain. Additionally, the team observed the reversal of fetal expression changes in Alzheimer’s disease findings reported in other studies. The research team also found that gene expression change is fastest in human brain tissue during fetal development, slows down through childhood and adolescence, stabilizes in adulthood, and then speeds up again after age 50, with distinct redirection of expression changes prior to birth and in early adulthood. The team’s findings were published in the October 27, 2011 issue of Nature. All of the data is available to the public as a web-based resource at: www.libd.org/braincloud. Using a number of genomic analysis technologies, the research team conducted genome-wide genetic (DNA) and gene expression (RNA) analyses of brain tissue samples from the prefrontal cortex. Tissue represented the various stages of the human lifespan. “We think that these coordinated changes in gene expression connecting fetal development with aging and neurodegeneration are central to how the genome constructs the human brain and how the brain ages,” said Dr. Carlo Colantuoni, one of the lead authors of the study and a former research associate with the Department of Biostatistics at the Johns Hopkins Bloomberg School of Public Health. Dr.
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