Have you made the trip to Dayton, TN, yet to see the image of Charles Darwin on a wall?
(Some say it's Stephen Jay Gould. Some say it's Carl Sagan. Some say it's a stain.)
Showing posts with label Charles Darwin. Show all posts
Showing posts with label Charles Darwin. Show all posts
Tuesday, September 09, 2008
Sunday, December 16, 2007
Viruses in genes
I hardly come across anyone who wants to say "evolution is just a theory." Maybe I'm lucky. Maybe I live in Switzerland. But next time I do, I'll pull out this bit from "Darwin's Surprise," by Michael Specter, The New Yorker, Dec. 3, 2007:
"Yet nothing provides more convincing evidence for the 'theory' of evolution than the viruses contained within our DNA. Until recently, the earliest available information about the history and the course of human diseases, like smallpox and typhus, came from mummies no more than four thousand years old. Evolution cannot be measured in a time span that short. Endogenous retroviruses provide a trail of molecular bread crumbs leading millions of years into the past.
Darwin’s theory makes sense, though, only if humans share most of those viral fragments with relatives like chimpanzees and monkeys. And we do, in thousands of places throughout our genome. If that were a coincidence, humans and chimpanzees would have had to endure an incalculable number of identical viral infections in the course of millions of years, and then, somehow, those infections would have had to end up in exactly the same place within each genome. The rungs of the ladder of human DNA consist of three billion pairs of nucleotides spread across forty-six chromosomes. The sequences of those nucleotides determine how each person differs from another, and from all other living things. The only way that humans, in thousands of seemingly random locations, could possess the exact retroviral DNA found in another species is by inheriting it from a common ancestor.
"Yet nothing provides more convincing evidence for the 'theory' of evolution than the viruses contained within our DNA. Until recently, the earliest available information about the history and the course of human diseases, like smallpox and typhus, came from mummies no more than four thousand years old. Evolution cannot be measured in a time span that short. Endogenous retroviruses provide a trail of molecular bread crumbs leading millions of years into the past.
Darwin’s theory makes sense, though, only if humans share most of those viral fragments with relatives like chimpanzees and monkeys. And we do, in thousands of places throughout our genome. If that were a coincidence, humans and chimpanzees would have had to endure an incalculable number of identical viral infections in the course of millions of years, and then, somehow, those infections would have had to end up in exactly the same place within each genome. The rungs of the ladder of human DNA consist of three billion pairs of nucleotides spread across forty-six chromosomes. The sequences of those nucleotides determine how each person differs from another, and from all other living things. The only way that humans, in thousands of seemingly random locations, could possess the exact retroviral DNA found in another species is by inheriting it from a common ancestor.
Molecular biology has made precise knowledge about the nature of that inheritance possible. With extensive databases of genetic sequences, reconstructing ancestral genomes has become common, and retroviruses have been found in the genome of every vertebrate species that has been studied. Anthropologists and biologists have used them to investigate not only the lineage of primates but the relationships among animals—dogs, jackals, wolves, and foxes, for example—and also to test whether similar organisms may in fact be unrelated."
Monday, November 26, 2007
A Book of Lives
I pour the amber
of a poem over it.
"1955, A Recollection"
*
No matter how beautiful that image is, it may imply a poetry that is static and reminiscent—and that is not at all what the poems in Edwin Morgan's A Book of Lives are. A long sequence called "Planet Wave," beginning with "In the Beginning (20 Billion BC)" and concluding with "On the Way to Barnard's Star (2300 AD)" bursts into splendid moments over and over again:
The earth dreams like a dog in a basket,
twitching, it likes to show it is alive.
"The Lisbon Earthquake (1755 AD)"
And look, a finch on the back of a tortoise
as if it had been listening
lifts its beak and begins a singing
so piercing it gives no end to that beginning.
"Darwin in the Galapagos (1835 AD)"
When Hendrix plucked, it was the mane of a lion.
"Woodstock (1969 AD)" [which concludes with a stunning poetic evocation of the fracturings of Hendrix's version of "The Star Spangled Banner"]
*
Long sequences seem to be where Morgan really comes into his own. "Gorgo and Beau" is a dialogue between two cells, one cancerous and one normal. Morgan gives the cruel "Gorgo" the stronger voice (à la Paradise Lost):
"Nothing is more boring than a well-made body."
Beau, the normal cell, is less biting but still beautiful:
"Each one of us is a world, and when its light goes out
It is right to mourn."
"Love and a Life" is a sequence of thirty-odd poems with a striking form: seven lines, the first four and the last relatively long (and varying in length), the fifth and sixth shorter, with an AAAABBA rhyme scheme. It works powerfully, and with enough variety to carry one through the whole sequence, which involves often extremely explicit recollections of (mostly?) gay love affairs. The most striking involves a man who talks Scots and does not want to leave his wife:
"'Ah love ma wife an ma weans. Ah don't go aroon thinkin aboot you day an night.
Ah wahnt tae come in yir mooth, an see thee teeth a yours—see they don't bite!
Ah like ye right enough, but aw that lovey-dovey stuff is pure shite."
of a poem over it.
"1955, A Recollection"
*
No matter how beautiful that image is, it may imply a poetry that is static and reminiscent—and that is not at all what the poems in Edwin Morgan's A Book of Lives are. A long sequence called "Planet Wave," beginning with "In the Beginning (20 Billion BC)" and concluding with "On the Way to Barnard's Star (2300 AD)" bursts into splendid moments over and over again:
The earth dreams like a dog in a basket,
twitching, it likes to show it is alive.
"The Lisbon Earthquake (1755 AD)"
And look, a finch on the back of a tortoise
as if it had been listening
lifts its beak and begins a singing
so piercing it gives no end to that beginning.
"Darwin in the Galapagos (1835 AD)"
When Hendrix plucked, it was the mane of a lion.
"Woodstock (1969 AD)" [which concludes with a stunning poetic evocation of the fracturings of Hendrix's version of "The Star Spangled Banner"]
*
Long sequences seem to be where Morgan really comes into his own. "Gorgo and Beau" is a dialogue between two cells, one cancerous and one normal. Morgan gives the cruel "Gorgo" the stronger voice (à la Paradise Lost):
"Nothing is more boring than a well-made body."
Beau, the normal cell, is less biting but still beautiful:
"Each one of us is a world, and when its light goes out
It is right to mourn."
"Love and a Life" is a sequence of thirty-odd poems with a striking form: seven lines, the first four and the last relatively long (and varying in length), the fifth and sixth shorter, with an AAAABBA rhyme scheme. It works powerfully, and with enough variety to carry one through the whole sequence, which involves often extremely explicit recollections of (mostly?) gay love affairs. The most striking involves a man who talks Scots and does not want to leave his wife:
"'Ah love ma wife an ma weans. Ah don't go aroon thinkin aboot you day an night.
Ah wahnt tae come in yir mooth, an see thee teeth a yours—see they don't bite!
Ah like ye right enough, but aw that lovey-dovey stuff is pure shite."
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