Common Descent – Part 2

Darwinian evolution predicted that organisms that share physical features will also share genetic information in common but genetic research has shown the opposite. Here is how one article recently published in the journal New Scientist puts it,

For much of the past 150 years, biology has largely concerned itself with filling in the details of the tree. “For a long time the holy grail was to build a tree of life,” says Eric Bapteste, an evolutionary biologist at the Pierre and Marie Curie University in Paris, France. A few years ago it looked as though the grail was within reach. But today the project lies in tatters, torn to pieces by an onslaught of negative evidence. Many biologists now argue that the tree concept is obsolete and needs to be discarded. “We have no evidence at all that the tree of life is a reality,” says Bapteste. That bombshell has even persuaded some that our fundamental view of biology needs to change.

Why Darwin was wrong about the tree of life
21 January 2009 by Graham Lawton

The article goes on to state that the evidence from DNA suggests that life is interrelated horizontally and not just vertically – like a spider web rather than the root system of a tree. This is not what genetic scientists expected if life evolved from a common ancestor.  The article then attempts to explain this anomaly.  Genetic material is not only transferred through reproduction but also on the sly by means of Horizontal Gene Transfer (HGT).  This is supposed to occur in three way:

1) endosymbiosis
2) viruses
3) hybrids

I don’t know enough to weigh in on the discussion but it will be interesting to see what comes of these new discoveries.  Who would’ve thought that we’d see the day when evolutionary biologists would call ‘the tree of life obsolete! 

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