mercredi, janvier 24, 2007
samedi, janvier 20, 2007
jeudi, décembre 28, 2006
"John Wilkins wonders about this in God, evolution and variation. I think it all boils down to purpose. Science doesn't reveal purpose but most religions demand it. (We're talking about interventionist Gods here.) Real evolution incorporates a large degree of accident and randomness and that's just not consistent with a God who has a plan. (Yes, I'm aware of the confused rationalizations of some theistic evolutionists.)"
This is from Larry Moran's blog, one of my favorites: Sandwalk. And this is one of the points of view I disagree mostly with fellows darwinists. Randomness is quite consistent with a god "who has a plan". At least there is evidence that Randomness and accidents and the so are quite consistent with humans "who have a plan" and want to achieve a results. And this is a case not rare for molecular biologists.
Now I'll have to explain. Imitating evolution in vitro is one of the most funny things I ever made in a lab. Random Mutation and Artificial Selection instead of RM+Natural Selection. I haven't a personal application/results to presnt here as much demonstrative as my chouchou, so I'll talk rather about DNA shuffling and the GFP -> EGFP construct.
DNA shuffling is a powerful technique when you don't have enough data to design a genetic manipulation to achieve a particular result, composed of a [predetermined] genotype leading to a particular phenotype. Not always easy to build the experiment.
First thing first, one need to [almost ;-)] precisely determine what the expecting result(s) is and a way to isolate it from a population. For EGFP the case was easy enough to be used as proof of concept: a DNA sequence, descendant of GFP, encoding for a protein with:
- better expression pattern in human cells, and/or
- higher quantum yield, and/or
- different excitation wavelength.
Building the Artificial Selection strategy was easy enough: express a DNA collection in human cells, illuminate with the desired wavelength, select the brighter cells using a cell sorter. A common cell sorter is the most complex part of the experiment's setting.
To apply this strategy one needs to have a population of DNA sequences to sort, indirectly, on the basis of the phenotype they procure. At this point DNA shuffling provides the answer. Starting with the parental GFP encoding DNA, introduce random mutations, cut the resulting molecules into short ones and allow PCR to recombine them. Purify (or not) the right length fragments, insert them into an eucaryotic expression vector, use the ligation product to transform the adequate cell line and let expression occur. Sort them; you may find the sequence(s) with the desired characteristics. You should find it if it is possible and your initial DNA population is large enough to covert probabilities.
Let's see what we have here: a quite intelligent designer mimicking evolution in vitro [random mutation and recombination] and applying selection for a particular set of characteristics. Someone "who has a plan" and build the conditions where "accidents and randomness" will bring the desired result. And it works. Nicely.
This one is an easy one, amongst an overwhelming pile of evidences, that should re-conciliate any theist around with Darwin: purpose, randomness and result. If a molecular biologist can do it, any god you can imagine could do the same.
Real evolution incorporates a large degree of accident and randomness and that's just not consistent with a God who has a plan.I think real evolution incorporates a large degree of accident and randomness quite consistent with any god who has a plan, and some knowledge of molecular biology. I'm not an atheist because gods couldn't play with DNA shuffling but because there is no evidence that such gods exist.
If theists are willing to believe the hypothesis of a god (or a set of them), let them do so and teach them that their beliefs aren't inconsistent with "evolution on the basis of RM+NS". So they hopefully stop interfere with evodevo and accept the mainstream theory of evolution without the feeling that they betray their god(s).
Even Intelligent Design proponents should stop talking about Design and start spending effort to improve Darwin's theory :-)
Dembski, O'Leary, do you copy me?
The same rationale can be used to discuss the transition from an abiotic state to the current biosphere on the basis of random events, or even from an a-universe state to the post-Bing Bang situation. Deities do have the right to use randomness and accidents (and the so) to achieve their goals, as any other entity. Now, proving that any deity exists is another problem, and it's not one for biologists but for theologists.
samedi, décembre 16, 2006
Puis je me suis réveillé en sursaut. Et j'ai eu envie de pleurer.
lundi, décembre 04, 2006
LiveScience.com - Scientist Fights Church Effort to Hide Museum's Pre-Human Fossils: "'The Christian community here is very uncomfortable that Leakey and his group want their theories presented as fact,' said Bishop Bonifes Adoyo, head of the largest Pentecostal church in Kenya, the Christ is the Answer Ministries.
'Our doctrine is not that we evolved from apes, and we have grave concerns that the museum wants to enhance the prominence of something presented as fact which is just one theory,' the bishop said."
"We have a responsibility to present all our artifacts in the best way that we can so that everyone who sees them can gain a full understanding of their significance," said Ali Chege, public relations manager for the National Museums of Kenya. "But things can get tricky when you have religious beliefs on one side, and intellectuals, scientists, or researchers on the other, saying the opposite."
samedi, décembre 02, 2006
Hybrids: When two species become three - life - 15 June 2006 - New Scientist: "SPECIES do not always arise by new branches forming on the family tree. Sometimes the branches merge, and two species hybridise to form a third."
When two butterflies become one new one - life - 01 December 2006 - New Scientist: "A new butterfly species that lives high in the Sierra Nevada mountains of the western US has turned out to be a rare creature indeed: it arose through the merging of two distinct species. It is one of very few hybrid species that can successfully breed."