Inside the secret defense systems of giant viruses

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STAT, February 29, 2016

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The strangest life forms on Earth just got a lot stranger.

In 2003, Didier Raoult of Aix-Marseille University in France and his colleagues discovered a new kind of virus lurking inside single-celled protozoans. Like other viruses, it couldn’t grow on its own, lacking the biochemical machinery to build proteins and genes. Instead, it had to infect host cells and use their material to produce new viruses.

But this new virus was enormous, measuring hundreds of times bigger than any previously known virus. What’s more, it was far more complex. Typical viruses may have just a few genes. The new virus had over 900 — more than many species of bacteria.

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Friday’s Elk, February 26, 2016

Posted on by Matt Kristoffersen

Greetings–

These days, I’m working on a book about heredity. This week I spent some time digging through the archives a historical society and came across this crazy pedigree from the early 1900s. At the time, the rediscovery of Mendel had set everyone abuzz, and a lot of scientists believed that everything was genetic–even boat building. (Note how some relatives were merely artistic, musical, mechanical, or literary. Heterozygotes, I guess…) Continue reading “Friday’s Elk, February 26, 2016” →

DNA Under the Scope, and a Forensic Tool Under a Cloud

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The New York Times, February 26, 2016

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Marina Stajic worked for nearly three decades as director of the forensic toxicology lab at the medical examiner’s office in New York City. Last week Dr. Stajic, 66, filed a lawsuit against the city, claiming she had been forced into retirement last year in part because of a disagreement with her superiors over the accuracy of certain DNA tests.

There is more at stake here than Dr. Stajic’s retirement. The cutting-edge technique at the center of this legal dispute, called low copy number DNA analysis, has transformed not just police work, but also a range of scientific fields including cancer biology, in vitro fertilization, archaeology and evolutionary biology. Yet some of the technique’s applications have triggered scientific controversy.

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Friday’s Elk, February 19, 2016

Posted on by Matt Kristoffersen

Greetings–

A great week for gene flow…
 

Humans and Neanderthals Get More Intimate

Over the past few years, I’ve written several pieces for The New York Times about how our ancestors interbred with Neanderthals and other extinct human populations (in 2010, 2013, 2015, and again in 2015). Now comes a cool study that appears to uncover even more gene flow–not going from extinct humans into our own gene pool, but in the other direction. I don’t know how many more of these big insights we will get in years to come. But it’s clear that our understanding about human evolution is becoming profoundly different from what you would have read in the textbooks twenty years ago. Continue reading “Friday’s Elk, February 19, 2016” →

In Neanderthals’ DNA, Ancient Humans May Have Left Genetic Mark

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The New York Times, February 17, 2016

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In 1997, scientists found the first scrap of Neanderthal DNA in a fossil. Since then, they have recovered genetic material, even entire genomes, from a number of Neanderthal bones, and their investigations have yielded a remarkable surprise: Today, 1 to 2 percent of the DNA in non-African people comes from Neanderthals.

That genetic legacy is the result of interbreeding roughly 50,000 years ago between Neanderthals and the common ancestors of Europeans and Asians. Recent studies suggest that Neanderthal genes even influence human health today, contributing to conditions from allergies to depression.

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