Posted on 08/16/2006 11:38:54 AM PDT by PatrickHenry
One of the fastest-evolving pieces of DNA in the human genome is a gene linked to brain development, according to findings by an international team of researchers published in the Aug. 17 issue of the journal Nature.
In a computer-based search for pieces of DNA that have undergone the most change since the ancestors of humans and chimps diverged, "Human Accelerated Region 1" or HAR1, was a clear standout, said lead author Katie Pollard, assistant professor at the UC Davis Genome Center and the Department of Statistics.
"It's evolving incredibly rapidly," Pollard said. "It's really an extreme case."
As a postdoctoral researcher in the lab of David Haussler at UC Santa Cruz, Pollard first scanned the chimpanzee genome for stretches of DNA that were highly similar between chimpanzees, mice and rats. Then she compared those regions between chimpanzees and humans, looking for the DNA that, presumably, makes a big difference between other animals and ourselves.
HAR1 has only two changes in its 118 letters of DNA code between chimpanzees and chickens. But in the roughly five million years since we shared an ancestor with the chimpanzees, 18 of the 118 letters that make up HAR1 in the human genome have changed.
Experiments led by Sofie Salama at UC Santa Cruz showed that HAR1 is part of two overlapping genes, named HAR1F and HAR1R. Evidence suggests that neither gene produces a protein, but the RNA produced by the HAR1 sequence probably has its own function. Most of the other genes identified by the study also fall outside protein-coding regions, Pollard said.
Structurally, the HAR1 RNA appears to form a stable structure made up of a series of helices. The shapes of human and chimpanzee HAR1 RNA molecules are significantly different, the researchers found.
RNA is usually thought of as an intermediate step in translating DNA into protein. But scientists have begun to realize that some pieces of RNA can have their own direct effects, especially in controlling other genes.
The proteins of humans and chimps are very similar to each other, but are put together in different ways, Pollard said. Differences in how, when and where genes are turned on likely give rise to many of the physical differences between humans and other primates.
Researchers at UC Santa Cruz, the University of Brussels, Belgium and University Claude Bernard in Lyon, France, showed that HAR1F is active during a critical stage in development of the cerebral cortex, a much more complicated structure in humans than in apes and monkeys. The researchers found HAR1F RNA associated with a protein called reelin in the cortex of embryos early in development. The same pattern of expression is found in both humans and rhesus monkeys, but since the human HAR1F has a unique structure, it may act in a slightly different way. Those differences may explain some of the differences between a human and chimp brain.
###
The chimpanzee genome was published in Nature in 2005, showing that the DNA sequences of humans and chimps are more than 98 percent identical. The current work was funded by the Howard Hughes Medical Institute, the U.S. National Institutes of Health and other agencies.
Which of the elements of evolution are not observable and have not been maipulated in the laboratory?
LOL -- Great response.
I make this point because I'm into math and computer science and the amount of data needed to build a human body is simply not contained in DNA. DNA appears to be to the human body as "screen properties choices" is to a PC.
It would help if you could elaborate your point here. How have you measured how much 'data' is required to build a human (or any other animal) body?
The fossil record continues to pile up with no contradictions. Will you need 1 million fossils? A billion? A trillion?
And no, humans and chimps are not alike. But we will not be like our descendants even 1000 years from now.
One thing is becoming clear: protein-coding genes may not be the movers and shakers of human evolution scientists once thought. "We should stop looking at proteins and start looking at non-coding DNA," says Lunter. "Everything points in that direction."
http://www.nature.com/nature/journal/v442/n7104/full/442725a.html
Definitions (from a google search, with additions from this thread):
Theory: a well-substantiated explanation of some aspect of the natural world; an organized system of accepted knowledge that applies in a variety of circumstances to explain a specific set of phenomena; "theories can incorporate facts and laws and tested hypotheses." Addendum: "Theories do not grow up to be laws. Theories explain laws." (Courtesy of VadeRetro.)
Theory: A scientifically testable general principle or body of principles offered to explain observed phenomena. In scientific usage, a theory is distinct from a hypothesis (or conjecture) that is proposed to explain previously observed phenomena. For a hypothesis to rise to the level of theory, it must predict the existence of new phenomena that are subsequently observed. A theory can be overturned if new phenomena are observed that directly contradict the theory. [Source]
When a scientific theory has a long history of being supported by verifiable evidence, it is appropriate to speak about "acceptance" of (not "belief" in) the theory; or we can say that we have "confidence" (not "faith") in the theory. It is the dependence on verifiable data and the capability of testing that distinguish scientific theories from matters of faith.
Hypothesis: a tentative theory about the natural world; a concept that is not yet verified but that if true would explain certain facts or phenomena; "a scientific hypothesis that survives experimental testing becomes a scientific theory"; "he proposed a fresh theory of alkalis that later was accepted in chemical practices."
Proof: Except for math and geometry, there is little that is actually proved. Even well-established scientific theories can't be conclusively proved, because--at least in principle--a counter-example might be discovered. Scientific theories are always accepted provisionally, and are regarded as reliable only because they are supported (not proved) by the verifiable facts they purport to explain and by the predictions which they successfully make. All scientific theories are subject to revision (or even rejection) if new data are discovered which necessitates this.
Law: a generalization that describes recurring facts or events in nature; "the laws of thermodynamics."
Model: a simplified representation designed to illuminate complex processes; a hypothetical description of a complex entity or process; a physical or mathematical representation of a process that can be used to predict some aspect of the process.
Speculation: a hypothesis that has been formed by speculating or conjecturing (usually with little hard evidence). When a scientist speculates he is drawing on experience, patterns and somewhat unrelated things that are known or appear to be likely. This becomes a very informed guess.
Guess: an opinion or estimate based on incomplete evidence, or on little or no information.
Assumption: premise: a statement that is assumed to be true and from which a conclusion can be drawn; "on the assumption that he has been injured we can infer that he will not to play"
Impression: a vague or subjective idea in which some confidence is placed; "his impression of her was favorable"; "what are your feelings about the crisis?"; "it strengthened my belief in his sincerity"; "I had a feeling that she was lying."
Opinion: a personal belief or judgment that is not founded on proof or certainty.
Observation: any information collected with the senses.
Data: factual information, especially information organized for analysis or used to reason or make decisions.
Fact: when an observation is confirmed repeatedly and by many independent and competent observers, it can become a fact.
Truth: This is a word best avoided entirely in physics [and science] except when placed in quotes, or with careful qualification. Its colloquial use has so many shades of meaning from ‘it seems to be correct’ to the absolute truths claimed by religion, that it’s use causes nothing but misunderstanding. Someone once said "Science seeks proximate (approximate) truths." Others speak of provisional or tentative truths. Certainly science claims no final or absolute truths. Source.
Science: a method of learning about the world by applying the principles of the scientific method, which includes making empirical observations, proposing hypotheses to explain those observations, and testing those hypotheses in valid and reliable ways; also refers to the organized body of knowledge that results from scientific study.
Religion: Theistic: 1. the belief in a superhuman controlling power, esp. in a personal God or gods entitled to obedience and worship. 2. the expression of this in worship. 3. a particular system of faith and worship.
Religion: Non-Theistic: The word religion has many definitions, all of which can embrace sacred lore and wisdom and knowledge of God or gods, souls and spirits. Religion deals with the spirit in relation to itself, the universe and other life. Essentially, religion is belief in spiritual beings. As it relates to the world, religion is a system of beliefs and practices by means of which a group of people struggles with the ultimate problems of human life.
Belief: any cognitive content (perception) held as true; religious faith.
Faith: the belief in something for which there is no material evidence or empirical proof; acceptance of ideals, beliefs, etc., which are not necessarily demonstrable through experimentation or observation. A strong belief in a supernatural power or powers that control human destiny.
Dogma: a religious doctrine that is proclaimed as true without evidence.
Some good definitions, as used in physics, can be found: Here.
Based on these, evolution is a theory. CS and ID are beliefs.
[Last revised 7/16/06]
True that, but I expect that is assumed :)
Here is a better question, why do we believe it is 3 billion polypeptides worth, which translates to 750mb, though we also hear that 99 percent is "junk", leaving a paltry 7.5 mb. It takes billions of bytes of data, inefficiently organized I admit, to build a car.
I love quantities and there are some amazing quantities involved, like the trillions of cells that make up the human body and the thousands of types of cells, the million of locations and the interconnections. If you know how much data was involved in controlling the communications between systems on the 787, which is a tinker toy compared to the human body, you'd understand why there is a serious problem with thinking DNA contains all the data needed to build a human body.
I'm not sure I understand this statement.
Are you saying that NDT says man directly evolved from the original proto-life?
Or are you saying that, while we have a common ancestor with Homo neanderthalensis, we do not have a series of common ancestors with other organisms?
Could you give an example of an Order level crossover?
Nothing personal, but this doesn't make any sense. Thank you for being straightforward.
Exactly analogous, as a matter of fact. It is only the behavior of the object, in your example, that is observable. It is an explicitly theoretical claim that the "forces of gravity" are responsible for the behavior.
Apparently not. It takes 2357 KB.
True ...
It is also worth mentioning that Behe, the reining guru of Intelligent Design, is on record as accepting common descent, and so is the webmaster for Dembski's site.
___________________________________________________________
So is this guy...
http://home.planet.nl/~gkorthof/kortho28.htm
I think most creationists don't take enough stock of the fact that while there are very few scientists who disavow common descent, there are quite a number with serious doubts that we have a good handle on the mechanism of evolution.
My position is that until we pin down the mechanism there needs to be at least some humility about the 'fact of common descent' even if there is tremendous evidence that appears to support it. Sort of like solving a murder without the weapon, you can do it, but it sure helps to find the weapon.
Of course many of the evolutionary advocates also don't like to mention the fact that mechanism is a lot more fuzzy than common descent.
Let's take care of the first question before we look at follow-ons. Your previous post made an interesting assertion, but I'm not yet persuaded that it is supported.
How are you measuring the amount of 'data' to 'build' a 'human body'? And how are you measuring how much 'data' (your term) is encoded in DNA?
"Trillions" of cells isn't the point (reiterations of a process do not entail significant additional 'data'); do you have a hard calculation here, or are you going on an intuitive supposition?
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.