* Heart of a Snake * Mastadon Massacre * The Fingerprint of Poverty * 7 Billion and Counting *



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Heart of a Snake

Leinwand python.jpgDr. Leinwand & friend.  photo: Thomas Cooper
The Burmese Python may be best known for its dietary habits: it constricts its prey - which can be as large as the snake itself - then swallows it whole.  And the python can go a full year without food.  Eating habits like this require special demands, among them increased blood flow.  That is why, after ingesting such a large meal, all of the python's internal organs - including the heart - nearly double in size.  New research by Dr. Leslie Leinwand, a Professor of Molecular Biology at the University of Colorado in Boulder has identified three fatty acids in the python's blood plasma that stimulate this rapid growth without causing damage to the heart.  It has been tested successfully in mice, and it is hoped that it can one day help people with damaged or diseased hearts.     

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Mastodon Massacre

CT scan "Fly through" of the mammoth bone. Courtesy Center for the Study of the First Americans
13,800 years ago, a group of unknown humans were hunting mastodons with spears in Northwest Washington State.  The evidence is a bone spear point, embedded in a mastodon rib, and the spear point itself was manufactured from mastodon bone as well.  Dr. Michael Waters, the Director of the Center for the Study of the First Americans at Texas A&M University in College Station, Texas, led a team that used DNA and protein analysis, high resolution CT scanning, and new dating technology to confirm the discovery.  This adds to the growing body of evidence to suggest that people were in North America and hunting large animals before the "Clovis peoples" who had been thought to be the first North Americans.
      

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The Fingerprint of Poverty

800px-DNA_methylation.jpg DNA tagged with methyl group - one kind of epigenetic change.  copyright Christoph Bock
An international collaboration has found what might be the biological fingerprint of poverty.  Dr. Moshe Szyf, a professor of Pharmacology and Therapeutics at McGill University, and his colleagues, have done a survey of the genome of a selected group of people who have been studied since the 1950s.  They were looking for what are called "epigenetic changes" to the DNA, which are a kind of temporary genetic reprogramming done to the DNA in utero and early childhood.  What they found was a very large variation in these changes between people who'd grown up in poverty and those who had grown up in privileged circumstances.  Dr. Szyf suspects that this is an adaptive response, which allows fast changes in the way DNA works, to adapt people for lives in good or poor circumstances.  However, he thinks that it also might be responsible for many of the diseases associated with childhood deprivation in the modern world.   

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7 Billion and Counting

crowd.jpgCrowds in Nanjing, China.  copyright Stephen Codrington
The United Nations estimates that on October 31st, the world's population will reach 7 billion.  Although the actual number is not certain, it does underlie the fact that our population is growing at an alarming rate.  It took until the early 1800's to reach the 1 billion mark, but the last 50 years alone have seen the births of 4 of the total 7 billion  This rapid increase raises the question, how many more people can the earth sustain?  Or have we already surpassed the earth's capacity?  Among the many people asking questions like this are Dr. Madeline Weld, President of the Ottawa-based Population Institute of Canada, and Robert Engelman, President of The Worldwatch Institute in Washington.  They discuss how various factors - including access to contraception, the empowerment of women, poverty, consumerism, and the environment - apply to our population growth, now and in the future.

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Theme music bed copyright Raphaël Gluckstein, Creative Commons License by-nc-nd-2.0