DNA, mRNA, and a theory

[Star Cannon]

(Note: I have a 10th understanding of mRNA and DNA, so refrain killing me!)

mRNA sends instructions to the ribosomes to make proteins, right? Well, what if the mRNA sent BACK information to the DNA to actually change DNA?

I kinda veiw DNA as the record of an individuals family, like they (their ancestors) went from a prokaryote to a eukaryote from to a lizard to an ape and all that info is stored there but we can't read it, right?

So, WHAT if we mapped out an individuals DNA at birth, waited 'til they died, MAP it again, and see if anything has changed. I think that would prove (or disprove) my theory. My hypothesis: the DNA would change over a lifetime. Why? If I told you this topic would be in the eventual spiritual forums.

[Star Cannon]

*tenth grade understanding, ahem.

[Lucas]

(Note: I have a 10th understanding of mRNA and DNA, so refrain killing me!)

mRNA sends instructions to the ribosomes to make proteins, right? Well, what if the mRNA sent BACK information to the DNA to actually change DNA?

I kinda veiw DNA as the record of an individuals family, like they (their ancestors) went from a prokaryote to a eukaryote from to a lizard to an ape and all that info is stored there but we can't read it, right?

So, WHAT if we mapped out an individuals DNA at birth, waited 'til they died, MAP it again, and see if anything has changed. I think that would prove (or disprove) my theory. My hypothesis: the DNA would change over a lifetime. Why? If I told you this topic would be in the eventual spiritual forums.

From what I understand(very little I might add), DNA does change. There are constantly errors made (mutations) in the replication process. However they are usually benign because they occur in the so called junk DNA. I don't know enough of the technical know how to say, but it's obvious that if DNA does change, it is on a very small and insignificant level. I don't think this is the driving force in evolutionary change. Organisms tend to go through very little change for long periods of time, then are punctuated by very short periods of great genetic change by selecting certain variations caused by genetic drift in the population. (whew, what a run-on sentence) The changing environment which fuels natural selection is responsible for short periods of punctuated genetic changes. If there was a constant genetic change, that gradually changed our ape ancestors into us we would see evidence for this in the fossil record. Most research seems to suggest that the gradualist model is flawed.

What genes are expressed, and why seems to be the important questions for me. Certain genes are turned on or off through environmental factors, and nobody seems to know much about this yet.

Mapping a persons DNA at the start and end of life would answer a lot of questions. But you have to consider that most DNA change or mutation occurs later in life for homo sapiens, well past being of age to pass genes on. I think mapping the differences between birth and say age 30 would be more appropriate because it would reflect how much these accumlated changes added up and changed us as a species.

Anyways, thats my two cents. Take it with a grain of salt, for I've been known to be full of mierda.
-Lucas

[lauriep]

Even if DNA does change over a lifetime, it wouldn't necessarily be passed onto the next generation and therefore influence evolution unless it was the gametes that were affected. Even then it would really only be a factor in men. For women, they are born with all of their reproductive material so DNA changes later in life it would still not be present in their offspring. However, for men, sperm is produced on more of as needed basis, so I guess it would be possible for DNA changes to be present and influence human evolution.

[Lucas]

it would be possible for DNA changes to be present and influence human evolution.

Is there any part of evolution that isn't the ultimate result of DNA changes?

[lauriep]

From my understanding, (I'm not a geneticist or anything) but DNA changes that influence evolution are mutations in the DNA of gametes. Assuming that one's DNA changes during their lifetime, a woman's reproductive DNA would not be affected by these lifetime DNA changes as her gametes' DNA has already developed at the time of her birth. For a male, sperm could be exhibit any DNA changes in a man's lifetime. However, either sex could still have mutations in gametes that occur in cellular division that would also be passed down to future generations.
I just don't think that measuring the differences in DNA in one's lifetime would be that critical in showing evolutionary change. Evolution in driven by the DNA mutations in gametes. Any mutations in the DNA carried in the gametes could be present at birth, particularly in females, and wouldn't necessarily change if the genetic code was mapped again at 30.

[Strephonade]

In much less cellularly complex organisms like bacteria, for instance, reverse transcriptase can effect a significant change in the DNA of a single organism. These changes can be passed on to subsequent generations of bacteria. The numerous and rapid ways in which bacteria evolve also present an interesting challenge for drug companies attempting to deal with resistant strains. On the flip side, there are cloning techniques that have been around for a while that use bacteria to produce various medicines. :)

[Odyssey]

Thanks for your thought!


Well, what if the mRNA sent BACK information to the DNA to actually change DNA?

I'd research it myself if I had time, but if I remember right, it does happen in prokaryotes by the name of reverse transcription -- [EDIT] haha, Strephonade beat me to it by 3 minutes!

~Odyssey

[Lucas]

I just don't think that measuring the differences in DNA in one's lifetime would be that critical in showing evolutionary change. Evolution in driven by the DNA mutations in gametes. Any mutations in the DNA carried in the gametes could be present at birth, particularly in females, and wouldn't necessarily change if the genetic code was mapped again at 30.

Female DNA only makes up roughly half of what is passed on. Because the other half does theoretically change throughout life, mapping the changes between birth and age thirty would reveal the average rate of genetic drift. Are you saying that female DNA never changes? Isn't there genetic variation (mutation) happening when the eggs are produced in the mother?

There is no gradual genetic change that solely drives evolutionary change. Genetic drift is only one of the four forces of evolution, the other three being mutation, natural selection, and gene flow. Although, the ultimate cause of all variation is mutation, which is just random DNA changes.

-Lucas

[lauriep]

Side note, have any of you ever read The Seven Daughter's of Eve by Bryan Sykes? Since mitochondria is strictly passed down through the mother, the book is about linking back lines of humans based on genetic differences in mitochondria. It's a short read but interesting.

[Helen]

I'd research it myself if I had time, but if I remember right, it does happen in prokaryotes by the name of reverse transcription -- [EDIT] haha, Strephonade beat me to it by 3 minutes!

~Odyssey[/quote]

Um, not exactly. Viruses aren't prokaryotes. Bacteria are.

[Odyssey]

Helen: Well yes, by prokaryotes I was indeed meaning mainly bacteria; because that's where I remember the process happening. Thank-you for reminding me that (retro)viruses are responsible.

~Odyssey