Genetics Question
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Mircea Grelus wrote:
It regenerates blood cells, skin, bones,
The liver too. It's an interesting thing--you can remove half a person's liver and it will regenerate. Quite painful, I hear though. Marc
Yes, a friend of mine had more than half hers removed, and she said the pain was unbelievable. Only pethidine made it just bearable.
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I guess the other question is, why do we age ? The answer probably is, if we were indestructable, and we could still breed, the world would have been overpopulated a long time ago.
Christian Graus - Microsoft MVP - C++ "also I don't think "TranslateOneToTwoBillion OneHundredAndFortySevenMillion FourHundredAndEightyThreeThousand SixHundredAndFortySeven()" is a very good choice for a function name" - SpacixOne ( offering help to someone who really needed it ) ( spaces added for the benefit of people running at < 1280x1024 )
That hints at a belief in design over evolution. If we diodn't age, we might well have been overpopulated, but it would introduce other reasons for not living very long, rather than aging. Ageing is cause by an imperfect copying DNA process during cell division, with defects slowly creeping into successive generations of cells.
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justfunnin wrote:
700-900 years old.
I heard [citation needed] they may have counted months, not years.
My father believes the literal interpretation, although acknowledges the years weren't exactly our twelve Gregorian months. His school believes several factors have resulted in an ever diminishing life span, starting with the fall, then the flood which separated water in the heavens, which provided serious cloud cover and protection from UV, to water on Earth, and the consequence of the fall that man was forced to begin eating flesh to survive after losing the guaranteed food supply of Eden. The narrow gene pool implied by the creationist argument is also held partly responsible for shortening lifespans.
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Sorry to hear about your condition Martin. I had a great grandfather who had both of his legs amputated because of a nerve disorder similar to paralysis. I have a degree in genetics and during my classes we talked about this somewhat. The general concensus was humans cannot regenerate full body parts because of cell specialization. When a human embryo is forming, the cells being produced are general, all-purpose cells (stem cells). As the embryo grows the cells begin to specialize becoming nerve cells, muscle cells, bone cells, etc. Once the fetus reaches about the third trimester almost all of the stem cells have become specialized. The closest thing to a stem cell in a newborn is the proto-cells in bone marrow (which produce blood cells throughout our life). So the answer to your question in short, we can't regenerate because we don't have any general cells to form specialized cells from. There are few specialized cells in the body that can divide. Skin cells, liver cells, bone marrow cells, and cancer cells are the only ones that I can think of that can reproduce. Contrary to popular belief, muscle cells DO NOT divide. Does any of that make sense? As for the "why do we age" question: three words "Programmed Cell Death". Believe it or not, our DNA is actually designed to kill us. We get wrinkles and saggy skin because the collagen and elastin protiens in our skin (which keep it tight) break down over time and our skin cells are not programmed to replenish it. Our bodies age because the cells in our organs are not programmed to mass reproduce and renew themselves. The few types of cells we have that can replenish themselves have a mechanism in them so that they only reproduce a preset number of times. After that, they die. Programmed Cell Death. And that concludes today's lecture.
FyreWyrm wrote:
DNA is actually designed to kill us
Is that an ID theory, or does your 'programming' evolve due to random mutations?
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:)
"mostly watching the human race is like watching dogs watch tv ... they see the pictures move but the meaning escapes them"
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Actually, our cells regenerate themselves every 7 years but doctors don't know why we age. One theory is, if you believe in God, as it says in the bible God set the age limit of man to 70-80 years because of all the wickedness in the world. Before that people were living to be 700-900 years old.
If you can read, you can learn
justfunnin wrote:
Actually, our cells regenerate themselves every 7 years but doctors don't know why we age.
The telomeres protecting the ends of our DNA get shorter with every cell division, so there is a limit to the number of times the cells can be regenerated without DNA damage increasing.
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FyreWyrm wrote:
DNA is actually designed to kill us
Is that an ID theory, or does your 'programming' evolve due to random mutations?
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Brady Kelly wrote:
Is that an ID theory, or does your 'programming' evolve due to random mutations?
actually it applies to both. In ID we angered the super-being and lost long lives, in evolution immortality is actually bad because no adaption can occur. Programmed death in evolution is a good thing, it allows change. Programmed death in ID is a punishment for bad behavior.
Marcus Cole: I used to think it was a terrible thing that life was so unfair. Then I thought, 'what if life *were* fair, and all of the terrible things that happen to us came because we really deserved them?' Now I take great comfort in the general unfairness and hostility of the universe._________________________ Asu no koto o ieba, tenjo de nezumi ga warau. Talk about things of tomorrow and the mice in the ceiling laugh. (Japanese Proverb)
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Brady Kelly wrote:
Is that an ID theory, or does your 'programming' evolve due to random mutations?
actually it applies to both. In ID we angered the super-being and lost long lives, in evolution immortality is actually bad because no adaption can occur. Programmed death in evolution is a good thing, it allows change. Programmed death in ID is a punishment for bad behavior.
Marcus Cole: I used to think it was a terrible thing that life was so unfair. Then I thought, 'what if life *were* fair, and all of the terrible things that happen to us came because we really deserved them?' Now I take great comfort in the general unfairness and hostility of the universe._________________________ Asu no koto o ieba, tenjo de nezumi ga warau. Talk about things of tomorrow and the mice in the ceiling laugh. (Japanese Proverb)
I just have difficulty using words that imply intent in connection with Evolution. I love the quote. :rose:
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FyreWyrm wrote:
Does any of that make sense?
Nope!
FyreWyrm wrote:
As for the "why do we age" question: three words "Programmed Cell Death". Believe it or not, our DNA is actually designed to kill us. We get wrinkles and saggy skin because the collagen and elastin protiens in our skin (which keep it tight) break down over time and our skin cells are not programmed to replenish it.
Can we ever reboot the human genome? I mean that my DNA (or so I am told) describes my physical form completely, is there anything can cause what's missing to reappear? (Actually, I heard this happen in reptiles... so why not us?)
Me: Can you see the "up" arrow? User:Errr...ummm....no. Me: Can you see an arrow that points upwards? User: Oh yes, I see it now! -Excerpt from a support call taken by me, 08/31/2007
Programmer's should find this easy to understand! As you specialize cells they become harder to change. Just like if you had one ancestor class that had been inherited over and over from subsequent generations of child classes. If you're an class at youngest leaf of this inheritance tree, then it very difficult to look and act like another leaf at the other side of the tree which has followed a completely different inheritance path. So when each of us starts out as a newly fertilized egg, we are a wee bag of cells that can be anything. However every time a cell splits, its child cells become a little bit more like a blood cell or a bone cell. And these similar cells hang around together creating more and more specialized versions of themselves. My biology isn't great, but I believe creatures that can regenerate have super-cool highly specialized cells that can create new similar cells. Us humans lost the the ability to do that millions of years ago as evolution decided it was worth the effort creating these cells. Probably because by the time a new leg had grown back, you'd already have been eaten by a sabre-tooth tiger!! HTH gogza
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I just have difficulty using words that imply intent in connection with Evolution. I love the quote. :rose:
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Brady Kelly wrote:
I love the quote.
Always been a favorite since a friend introduced me to the series. :-D
_________________________ Asu no koto o ieba, tenjo de nezumi ga warau. Talk about things of tomorrow and the mice in the ceiling laugh. (Japanese Proverb)