A Crispr Conundrum: How Cells Fend Off Gene Editing

Posted on June 12, 2018May 25, 2020 by Zimmer

The New York Times, June 12, 2018

Human cells resist gene editing by turning on defenses against cancer, ceasing reproduction and sometimes dying, two teams of scientists have found.

The findings, reported in the journal Nature Medicine, at first appeared to cast doubt on the viability of the most widely used form of gene editing, known as Crispr-Cas9 or simply Crispr, sending the stocks of some biotech companies into decline on Monday.

Crispr Therapeutics fell by 13 percent shortly after the scientists’ announcement. Intellia Therapeutics dipped, too, as did Editas Medicine. All three are developing medical treatments based on Crispr.

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Hot Heads: Why Mammals Need R.E.M. Sleep

Posted on June 7, 2018May 25, 2020 by Zimmer

The New York Times, June 7, 2018

Link

On a December evening in 1951, Eugene Aserinsky, a physiologist at the University of Chicago, placed electrodes on the scalp of his 8-year-old son, Armond, before putting him to bed. Then the scientist retired to another room to watch a row of pens quiver across a rolling sheet of paper, recording the electrical activity in the boy’s facial muscles.

Hours later, the pens started to swing wildly. To judge from the chart, it seemed as if Armond were awake, his eyes darting about the room. But when Aserinsky looked in on him, his son was fast asleep.

Aserinsky had discovered R.E.M. sleep.

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The Great Breakup: The First Arrivals to the Americas Split Into Two Groups

Posted on May 31, 2018May 28, 2020 by Zimmer

The New York Times, May 31, 2018

Link

Early inhabitants of the Americas split into two populations over 13,000 years ago, according to a new study of ancient DNA, and remained separated for thousands of years.

Eventually, somewhere, the two groups met again and began commingling. Today, their descendants inhabit a vast region stretching from Mexico to the southern tip of South America.

The research, published on Thursday in the journal Science, paints a complex picture of human migrations through the Americas. When people arrived in the Western Hemisphere from Asia, they didn’t just move to new territories and settle down.

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