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Originally Posted by
juroara
DNA is covered in a protein casing.
Not true.
DNA is not covered in protein casing. DNA is wrapped around proteins called histones.
http://en.wikipedia.org/wiki/Nucleosome
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The cell has to un-zip this protein casing itself for DNA to do anything.
No it doesn't. The transcription machinery 'unzips' the double strand (DNA), not the proteins because only one strand on DNA is used as a template for reading information needed to build proteins.
The nucleosome does provide a hindrance for the transcription machinery, but not all of the time because DNA is not fixed with the histones all the time.
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Therefore DNA simply sits there until the cell engages in it.
DNA stores information. It stores information when 'cell engages in it', it stores information when it doesn't, it stores information even when it's outside of the cell.
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The cell engages with it's DNA because of environmental factors, and if you don't believe me, please watch Biology of Belief/Perception by Bruce Lipton. He's the cell biologist, not me.
DNA is read every time any of the genes is being transcribed.
Some genes are transcribed as a response to environmental changes, some are not. Either way, proteins and DNA interact constantly.
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But what determines the EXPRESSION of those genes?
Some are constitutively(all the time) expressed, some are expressed as a consequence of the signals coming from other parts of the cell, some are expressed as a consequence of signals from outside.
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Take for example that some people have a cancer genes.
There are no 'cancer genes'. Those are just genes with normal functions that were somehow mutated so their functions became abnormal. Those aberrant variants increase the likelihood of getting cancer.
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Well this gene isn't expressed at birth, or else they would have died at a young age!
1. A lot of them do die at young age: 25-30% of ALL pregnancies end in spontaneous abortion. 50% of those fetuses die as a result of different genomic aberrations.
2. Hereditary cancer is usually inherited as a single aberrant copy. That means those people have one normally working copy of the gene. In many cases they don't develop cancer until later in life, when they lose the other copy that was functional.
3. There's also sporadic cancer that has no hereditary component, it's a result of accumulated mutations. This usually takes years to develop.
4. Most types of cancer take years to develop
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Not all genes are automatically expressed at birth.
So what expresses them later in life?
I never said they were.
"Some are constitutively(all the time) expressed, some are expressed as a consequence of the signals coming from other parts of the cell, some are expressed as a consequence of signals from outside."
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But it doesn't come first. That which expresses the genes comes before the expression of those genes.
That which expresses the genes is the activity of transcription factors and their interaction with chemical signals from inside and outside of the cell.
Transcription factors are proteins.
Proteins are encoded in the DNA (genetically determined)
The way proteins interact with signals from outside and inside, and the way they interact with DNA is encoded in the DNA - it's genetically determined.
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I didn't say that random mutations do not occur. I said that mutations aren't as a whole, as random as we think. Just as there are experiments that show how mutations are random, so to are there experiments that lead to the opposite conclusion. In other words, sometimes mutations are random, sometimes they are not.
I'll grant you that there are certain parts of the genome that are more likely to undergo mutation. However, 'the same mutation' is far from meaning the same as the 'mutation in the same region of the genome'.
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It's talked about in my book. So I don't know of any website off hand. I'll have to do some digging around first.
Take any book on cell biology or genetics, and you'll get some understanding if you're really interested. Don't use Bruce Lipton's books as a resource on biology because they have nothing to do with biology.
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I think DNA serves as a blueprint, a code of sorts to a program. But it is not the program.
The cell can only have functions that are stored in the DNA. The program is dynamic because it has to respond to different conditions. But it's still a program.
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While hypermutation is extremely exceptional, it could be one of the most important and fundamental forms of mutation.
There's nothing fundamentally special about it.
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What is one of the arguments that creationists use against evolution? Well diversity! In evolution there are certain time peroids where life just seems to explode with diversity at such a faster rate than the normal and slower and more predictable evolution. Because the evolutionary rate in these time periods happen so much quicker, creationists are able to poke holes in the theory. They are only able to poke holes in the theory because the theory isn't yet complete.
These explosions of diveristy always happen when the environment becomes critically stressful. Hypermutation might hold a key to understanding the explosion of diversity in these environmental stressful times in evolution.
Hypermutation has been know about for more than 40 years and well understood as one of the many mechanisms of molecular evolution.
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Obviously, such a mutation would only lead to cancer in an adult being.
It happens ALL the time in adult beings, it's a normal part of any immune response. It's also a risky way of repairing DNA damage that can't be repaired otherwise.
Sometimes it causes cancer, yes.
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There is an exception though. And that's the womb.
No, it happens less frequently in the womb - the immune system fully develops after birth.
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Let's face it. The dinosaurs couldn't evolve fast enough. The mammals could. Mammals had a new evolutionary feat on their side, the womb.
Let's face it. This 'theory' makes no sense.
A lot of mammals became extinct the same time dinosaurs have. They go extinct all the time.
What about plants, they don't have wombs, how can they still be alive?
Or birds? Or reptiles?
Or any non-mammal?
Also, bacteria and viruses don't have wombs and evolve a couple of orders of magnitude faster than humans.
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Bruces work offers us a new idea of how evolution may work in higher conscious mammals at least.
Bruce is just selling his books to people with no basic understanding of biology
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Would it be impossible to imagine that if a mother is in extreme environmental stress that she can actually spur her unborn child to evolve to better match the environment?
It's more likely that it will cause a miscarriage.
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Please watch the video to understand where I'm coming from.
Bruce Lipton is a fraud.
He also isn't saying anything new. In 1961. Jacques Monod discovered how gene expression can be regulated depending on the nutrients available in the environment. It's not like Lipton is presenting a scientific revolution. He's just bastardizing well know facts.
If you're interested in biology, read books on biology, don't listen to this crap.