Genome complexity: epigenetics histones (Introduction)

by David Turell , Thursday, October 15, 2015, 05:31 (3114 days ago) @ David Turell

Histones are spools around which DNA winds to fit into the nucleus. Modifying histones can change inheritance for two generations out:-http://www.sciencedaily.com/releases/2015/10/151008142622.htm-"The researchers were curious about whether histones might play a role in transmitting heritable information from fathers to their offspring because they are part of the content of sperm transmitted at fertilization. Histones are distinct from our DNA, although they combine with it during cell formation, acting a bit like a spool around which the DNA winds.-"So, to test their theory about the possible role of histones in guiding embryo development the researchers created mice in which they slightly altered the biochemical information on the histones during sperm cell formation and then measured the results. (It's a bit like putting a nick in a spool of thread and seeing how it affects the way the thread then loops around the spool.) They then studied the effects on the offspring.-"What they discovered was that there were dire consequences for the offspring both in terms of their development e.g. where offspring were prone to birth defects and had abnormal skeletal formation, and in terms of their surviving at all. Moreover, what was most surprising, was that these effects could still be seen two generations later.-"'When we saw the decreased survivability across generations and the developmental abnormalities we were really blown away as it was never thought that altering something outside the DNA, i.e. a protein, could be involved in inheritance," said Sarah Kimmins, from McGill's Dept. of Animal Science, and one of the lead authors on the paper.-"Kimmins added, "These findings are remarkable because they indicate that information other than DNA is involved in heritability. The study highlights the critical role that fathers play in the health of their children and even grand-children. Since chemical modifications on histones are susceptible to environmental exposures, the work opens new avenues of investigation for the possible prevention and treatment of diseases of various kinds, affecting health across generations.'"-Comment: the demonstrated complexity of the genome continues to increase beyond an possibility it occurred naturally.