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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Friday’s Elk, February 12, 2016

Posted on by Matt Kristoffersen

Greetings–

My first cold of the season slowed down this week’s newsletter. Between the sniffles, here we go:
 

Viruses and Birth Defects

As Zika virus spreads through the Western Hemisphere, scientists are investigating whether it’s responsible for a burst of birth defects in Brazil, known as microcephaly. In this week’s Science Times section of the New York Times, I wrote about other viruses, like rubella and cytomegalovirus, that can also harm a fetusif they infect a pregnant woman. Those lesser-known are providing a guide for research on Zika–but we still don’t understand a lot of their biology. Continue reading “Friday’s Elk, February 12, 2016” →

A Parasite, Leopards, and a Primate’s Fear and Survival

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The New York Times, February 11, 2016

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Many of our primate ancestors probably ended up in the bellies of big cats. How else to explain bite marks on the bones of ancient hominins, the apparent gnawing of leopards or other African felines?

Big cats still pose a threat to primates. In one study of chimpanzees in Ivory Coast, for example, scientists estimated that each chimp ran a 30 percent risk of being attacked by a leopard every year.

A new study suggests that the big cats may be getting some tiny help on the hunt. A parasite infecting the brains of some primates, including perhaps our forebears, may make them less wary.

Continue reading “A Parasite, Leopards, and a Primate’s Fear and Survival” →