DNA tags mostly deleted in human germ cells | Science News

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DNA tags mostly deleted in human germ cells

The few epigenetic markers that escape erasure might pass on risk for some diseases

By
12:00pm, June 4, 2015
embryo

EARLY ERASER  Sometime in the first trimester, human embryos’ reproductive cells get wiped mostly clean of chemical tags marking the DNA.

Mom and dad’s lifestyle may leave less of a mark on future generations than scientists have suspected.

In the first weeks after conception, some of the cells in human embryos get their genetic blueprints scrubbed clean, conclude three new studies published June 4 in Cell. Those cells, the ones that become sperm or eggs, could beget the tiny embryos’ future offspring.

The genetic scrub-down erases notes that environmental factors write on parents’ DNA, so that a child’s sperm or eggs start off with a clean slate — mostly. One study revealed that a few spots in the genome, the complete set of DNA blueprints, avoided the cleanse. So a few of the DNA notes that people rack up during their lives could potentially pass from generation to generation, possibly transmitting risk for diseases such as schizophrenia far down the family tree.

“But by and large, this paper

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