
Blue-eyed humans have a single, common ancestor
There's quite a resemblance, don't you think?
What may have been the most fascinating part of the afternoon was my time in the Government Lobby. Behind the curtains that run along the last row of benches on both sides of the House, are doors to long skinny living room areas. One is called the Opposition Lobby; the other the Government Lobby. In my pre-Green Party leader life, I have spent a lot of time in both. The Government Lobby was a frequent work space when I was Senior Policy Advisor to the federal Minister of Environment back in the mid-1980s. And I frequented both lobbies when I was with Sierra Club of Canada from 1987-2006. It did not strike me until I walked into the Government Lobby to await my turn as Speaker that I had not been in there since Stephen Harper became Prime Minister.
It used to have some paintings on the wall. Past prime ministers, certainly a formal portrait of the Queen. Landscapes. I know there was the occasional photo of current Prime Ministers, but when I walked in this time, I felt chilled to the bone. Every available wall space had a large colour photo of Stephen Harper. Stephen Harper at Alert. Stephen Harper in fire fighter gear. Stephen Harper at his desk. Stephen Harper meeting the Dalai Lama. Even the photo of the Queen showed her in the company of Stephen Harper. None were great photos. None were more than enlarged snapshots in colour. They didn’t feel like art.
Your Majesties, Your Royal Highnesses, Ladies and Gentlemen,
The chemical reactions which take place in living organisms are not spontaneous, but require the involvement of catalysts. These catalysts are called proteins and are composed of chains of amino acids called peptides. A number of hormones and other substances which regulate different life processes are also peptides. There are about 20 naturally occurring amino acids which are found in such peptides and since the chains can be very long, the number of possible variations is virtually unlimited.
Today we know the structures of a very large number of proteins and peptides. Important contributions to this area of knowledge were made by Fredrick Sanger, who received the Nobel prize in 1958, and Stanford Moore and William H. Stein, Nobel prizewinners in 1972. A very important contribution was also made by the Swedish researcher Per Edman, who unfortunately died relatively young and whose method for the controlled degradation of peptides is now generally used.
The chemical synthesis of peptides is an important task. The principle used in such synthesis is simple and was developed a relatively long time ago by Emil Fischer, who received a Nobel prize in 1902, although for completely different discoveries. Expressed simply, this principle involves the binding together of two amino acids which have been appropriately modified to give a dipeptide. This dipeptide is then combined with a third modified amino acid to give a tripeptide and so on.
Even if the principle is simple, in practice it is difficult to synthesize peptides, since a large number of individual steps is involved. After each step the desired product must be separated from by-products and unreacted starting material and this takes time and involves loss of the product. When Vincent du Vigneaud synthesized a peptide hormone, oxytocin, which is a nonapeptide, for the first time, this represented a great step forward which was rewarded with the Nobel prize for 1955. To use a similar approach for synthesizing a peptide containing 100 or more amino acid residues is truly a heroic task, requiring a very large amount of work and chemicals. This task can be compared to climbing a high mountain peak in the Himalayas, which begins with a large expedition carrying much equipment and ends, if all goes well, with a few lightly equipped alpinists reaching the top.Therefore, Merrifield's development during the 1960's of a method for carrying out peptide synthesis on a solid matrix revolutionized the field. He attached the first amino acid to an insoluble polymer, a plastic material in the form of small spheres. Subsequently, the other amino acids were added one after one and only after the entire peptide chain had been synthesized was it released from the polymer. The advantages of this method are considerable. The complicated purification of the product after each synthetic step is replaced by simply washing the polymer to which the peptide is attached, so that loss of product is avoided completely. At the same time, the yield for each individual step is increased to 99.5% or better, a goal which cannot be achieved with conventional methods, but which is extremely important in syntheses involving a large number of steps. Finally, this method can be automated and automatic peptide synthesizers are now commercially available.
Thousands of different peptides of different sizes, as well as proteins, peptide hormones and analogues of these compounds have now been synthesized using this method. One milestone in this respect was the synthesis of an active enzyme, ribonuclease, containing 124 amino acid residues, by Merrifield and his coworkers.
The approach of performing a multistep synthesis with a compound attached to a solid matrix as the starting material has also been used in other areas. The most important of these is undoubtedly the synthesis of oligonucleotides, which are needed in hybrid DNA research. In this case as well an automated apparatus which can be programmed to synthesize desired products has been constructed. Although Merrifield has not worked in this area himself, it is clearly his ideas which have found a new application here.
Professor Merrifield,
Your methodology for chemical synthesis on a solid matrix is a completely new approach to organic synthesis. It has created new possibilities in the fields of peptide-protein and nucleic acid chemistry. It has greatly stimulated progress in biochemistry, molecular biology, medicine and pharmacology. It is also of great practical importance, both for the development of new drugs and for gene technology.
On behalf of the Royal Swedish Academy of Sciences I wish to convey our warmest congratulations and ask you to receive your prize from the hands of His Majesty the King.
A young Arkansan asks Mike Huckabee what should be done about schools not teaching evolution properly. The former governor then advocates what the student has already said was against state standards...that schools should teach creationism because evolution's only a theory.Huckabee is entitled to his opinion about creationism, of course, but what troubles me is his statement that evolution is only a theory. Most of us don't (usually) make statements about things that we know nothing about. I can't believe that Huckabee is completely ignorant about the basic facts of biology. Somebody must have told him at some time during his life that evolution is overwhelmingly supported by solid scientific evidence.
Warning: The Structure of Evolutionary Theory is written at a very high level. It's not for high school students. If the language and style turns you off then maybe it's not for you. Try Dawkins or Dennett. Their version of evolutionary theory can be understood by 5th graders.
Now, I would like to ask you a few short questions like those you might see on a television game show. For each statement that I read, please tell me if it is true or false. If you don't know or aren't sure, just tell me so, and we will skip to the next question. Remember true, false, or don't know. i. Human beings, as we know them today, developed from earlier species of animals. (Is that true or false?)The overall results are not surprising. They have been discussed before. About 50% of Americans accept the fact of evolution and about 50% reject scientific facts.
[Hat Tip: Gene Expression]
Death Watch and Health WatchTo find out why this isn't the end of rationality and the triumph of superstition, check out Way of the Woo. The surprise isn't that Nikki is a liar, it's that so many people fall for it.
Annette Funicello, Hillary Clinton, Doris Day, Willie Nelson, Pamela Lee Anderson, Loretta Lynn, Ted Kennedy, Unice Shriver, Fidel Castro, Hugo Chavez, Benazir Bhutto, President Masharaff, Billy Graham, Jerry Lewis, Chareleton Heston, Tony Curtis, Debbie Reynolds, Heath Ledger, Barack Obama, Zsa Zsa Gabor, Nelson Mandela, Farah Fawcett, Nancy Reagan, Dick Cheney, Dick Clark, Elizabeth Taylor, Larry King, Suzanne Pleshette, Mick Jagger, Arnold Schwarzeneger, Kirk Douglas, Hugh Hefner, Shirley Temple Black, Alex Trebek, and French President Sarkozy.
[Photo Credit: Graduate students in the Department of Biochemistry 2007-2008.]
1. Here's an interesting bit of trivia. How many ScienceBlogTM authors have won the free lunch? How many have guessed the correct answer even though they weren't the first to do so? The answers might surprise you.
The number of vertebrae in different species of snakes varies from about 200 to 350. Since all snakes are cousins of each other, and since vertebrae cannot come in halves or quarters, this must mean that from time to time, a snake is born with at least one more, or one fewer, vertebra than it its parents. These mutations deserve to be called macro-mutations, and they have evidently been incorporated in evolution because all these snakes exist.I think it's safe to say that the concept of macromutations and saltations is not ruled out in evolution although it is certainly rare. Gould makes the point in his essay that this kind of evolution, while dramatic, is Darwinian.
The idea of macromutational hopeful monsters, or "saltations," had a prominent resurrection in 1980 when Stephen Jay Gould, as part of his and Niles Eldredge's theory of punctuated equilibrium, proposed that macromutations could explain the "jumps" in the fossil record. After getting a severe drubbing from geneticists, Eldredge and Gould retreated in 1993, claiming that they never suggested the idea of saltations.The idea that Gould's example of hopeless monsters was connected to punctuated equilibria is not correct. This is the same mistake that Greg Laden makes in his discussion of the topic [Hopeful Monsters and Hopeful Models]. Greg says,
The second reason is that the fossil record seems to have the property whereby many species stay roughly similar for long periods of time, then suddenly, there is lots of evolutionary change. You've heard of this, it's called "punctuated equilibrium." If hopeful monsters ... also called saltational (dancing, leaping) evolution ... occurred generally, we might postulate that these moments of dramatic change, these punctuations, are periods in time where for some reason a lot of hopeful-monstering was going on all at once. That would be cool.Let's be very clear about what punctuated equilibria are and what they aren't. The pattern of punctuated equilibria show that speciation by splitting (cladogenesis) is associated with morphological change. The actual speciation event is relatively rapid (in geological time) and the end result is a morphologically distinct sibling species where the changes were not evident in the population before the split. The most common explanation is that variants in the larger population were enriched in a small founder population that went on to speciate. It's an example of random genetic drift, or possibly selection, but no new mutations have occurred.
But did they? I must admit that I thought they did until Steve Gould insisted to me that I should check all his various publications, and see for myself that his opponents were foisting a caricature on him.Dennett checked, and found that Gould was right. To his credit, he reports that this claim about saltation being part of punctuated equilibria is wrong. Dennett concludes on p. 289-290.
"Punctuated equilibrium is not a theory of macromutation" (Gould 1982, p.88). Confusion on this score still abounds, however, and Gould has had to keep issuing his disclaimers [as has Eldredge, LAM]: "Our theory entails no new or violent mechanism, but only represents the proper scaling of ordinary events into the vastness of geological time" (Gould 1992b p.12).I'm quoting Dennett here instead of quoting Gould and Eldredge1 directly because Dennett is one of Gould's fiercest opponents. If Gould's worst enemy can see the truth then why is this myth still being propagated?
So this was the false-alarm revolution that was largely if not entirely in the eyes of the beholders.
Nonetheless, we were accused of being saltationists. Steve Gould wrote two consecutive essays in Natural History in 1977. Among other things, Steve speculated that the recent (sic) discovery of regulatory genes—genes that turn other genes on and off—raised the possibility that mutations in the regulatory apparatus might occasionally have the sort of effect Goldschmidt had in mind with his notion of 'macromutations.' These macromutations had the large-scale effects of the sort he posited for his 'hopeful monsters.' Nowhere in either article did Steve mention punctuated equilibria.
But it was enough, it seems, that he, champion of a new model positing bursts of relatively rapid change, would, a few years later, discuss Goldschmidt in favorable terms. Mayr was one of the first to level the charge that punctuated equilibria was nothing but old saltationism in new guise. Our debt to Mayr's concept of species and speciation, so central to the idea of punctuated equilibria, eventually induced him to do an about face. Mayr came to prefer taking credit for punctuated equilibria rather than seeing it linked to his old nemesis Goldschmidt.
Dawkins, R. (1996) Climbing Mt. Improbable W.W. Norton & Company, New York.
Dennett, D. (1995) Darwin's Dangerous Idea. Simon & Schuster, New York.
Eldredge, N. (1995) Reinventing Darwin. John Wiley & SOns, Inc., New York
Where does Darwin stand on the matter of a personal God? "The old argument of design in nature, as given by Paley, which seemed so conclusive, fails now that the law of natural selection has been discovered. We can no longer argue that, for instance, the beautiful hinge of a bivalve shell must have been made by an intelligent being, like the hinge of a door by a man" (Darwin 1958, p.87). Darwin seems to reject the idea of a personal God and, therefore, theism too. His religious views are difficult to pin down (Browne, 2006, p.46), but something close to deism would seem to fit.There seems to be general agreement that Darwin did not subscribe to the tenets of any organized religion. There is debate over whether he believed in supernatural beings. His Grandfather, father, and brother were non-believers so it's reasonable to suppose that Darwin was too.
Theism is a belief in a personal God, one who responds to prayers and interferes in daily events; atheism is the opposite of theism. Deism is the belief in a God who set the universe in motion whit all the physical laws and both sacred and learned commentaries, but was absent after that. In practice, deism is much like atheism.
Browne, Janet (2006) Darwin's Origin of Species: A biography. Douglas & McIntyre Vancouver/Toronto.
Darwin, Charles (1958) The Autobiography of Charles Darwin, Nora Barlow ed. W.W. Norton and Company, New York.
Take the junk DNA quiz in the left sidebar to let me know what you think of your genome. How much of it could be removed without affecting our species in any significant way in terms of viability and reproduction? Or even in terms of significant ability to evolve in the future? In other words, how much is junk?It's important to register your choice now. You'll get another chance to vote on a similar topic in February and it will be fun to compare the two polls.
[Image Credit: The junk DNA icon is from the creationist website Evolution News & Views.]