Genetic damage

[bugmenot]

Do humans lose genetic information as time goes on?
Everyone knows that when something is copied like data on a PC the data always loses some of it's identity. For example. If I make copies of an audio CD over and over but not using the original every time and using the last copy made to make another copy the data always gets worse in quality. It's the same process as human reproduction. Does that apply to DNA? If not how is DNA preserved in human generations?

If what I think is true what will be the first thing that will suffer as a result of DNA damage?
Will it be the reproductive system? Will humans lose the ability to reproduce in the near future because of DNA damage?

What other factors can cause DNA damage other than radiation and DNA copies if true?

I think that DNA from any living thing gets lost as time goes on and it gets worse in quality as time goes on. The most vurnerable system in all of living things is the reproductive system and I also believe that DNA damage will lead to extinction. Am I correct?

[alxian]

as per your example the loss of quality is non existant to negligable when dealing with digital information

you only lose quality if you use compression. making dupes of a cd to a cd is not the same as duping a vhs cassette.

(though the longer you use a duped cd the more it ages and ripens, eventually you'll lose quality but nothing noticeable if you are using quality blanks)

----
as for genetic damage [in humans]

ultraviolet radiation

toxins, smoking, drugs, alcohol?

inbreeding

there are many ways to corrupt our genome

viruses can be blamed for some damage (and some beneficial mutations too)

disease

heavy doses or prolonged exposure to ionized particles, such as ozone created from sparks or lightning.. it causes cancer, i'm not sure about communicable genetic damage.

our dna is flawed before trying to breed it, breeding it may make the bad dna ressessive but if there is no healthy dominant trait the bad dna is expressed.

very little is being done to clean it our genome.
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if this is the same with dna. degredation with each new human of woman born?

its not that black and white, our dna is engineered to fix itself, bad dna becomes recessive and good dna, the beneficial mutations (the more a mutant breeds the more the trait is spread around the more dominant it becomes).

so imo, no, degredation doesn't really happen the way it would in the cassette duping example, but neither does dna copy bit for bit. mainly because it isn't being copied. that would be cloning (which if memory serves dna does degrade with each serial clone). but adding two different stocks together to form one unique person benefits greatly from more dominant dna and the ability to ignore recessive traits.
--
digital dna... could there be a way to make dna as stable as the binary bits of a computer?

four bits on their own seems to be a stable enough system but during the splicing and merging of the parental and maternal code the unique offspring sometimes have anomalies. would making dna binary solve this problem? what about efficiency? if our genome was purged of junk chains would the reduced and purified strings in binary formation be more or less efficient than keeping the old gatc system?

OTOH what about using more than only a pair of nucliecs base pairs, why not have 3 pairs and make our genome even more efficient (once cleaned up). are Purine and Pyrimidine compatible enough to form a third base pair? (or a terciary base pair of adenine and uracil) a base pair that could be used as a backup in case anomolies crop up. the third pair can read off changes.. like a federally mandated universal base pair, an unmodifyable dataset of everything "human".
----
if anything would noticeable suffer from expression of recessive traits or other forms of damaged dna then it would be the brain, the skin, hair, things you can see.

basic systems like digestion, reproduction can be affected but you can live a normal life and hide such defects more easily that splotchy skin or slurred speech.

[bugmenot]

Thx for that. Great explanation.

[EWright]

Originally Posted by alxian

as per your example the loss of quality is non existant to negligable when dealing with digital information

you only lose quality if you use compression. making dupes of a cd to a cd is not the same as duping a vhs cassette.

(though the longer you use a duped cd the more it ages and ripens, eventually you'll lose quality but nothing noticeable if you are using quality blanks)

----
as for genetic damage [in humans]

ultraviolet radiation

toxins, smoking, drugs, alcohol?

inbreeding

there are many ways to corrupt our genome

viruses can be blamed for some damage (and some beneficial mutations too)

disease

heavy doses or prolonged exposure to ionized particles, such as ozone created from sparks or lightning.. it causes cancer, i'm not sure about communicable genetic damage.

our dna is flawed before trying to breed it, breeding it may make the bad dna ressessive but if there is no healthy dominant trait the bad dna is expressed.

very little is being done to clean it our genome.
----
if this is the same with dna. degredation with each new human of woman born?

its not that black and white, our dna is engineered to fix itself, bad dna becomes recessive and good dna, the beneficial mutations (the more a mutant breeds the more the trait is spread around the more dominant it becomes).

so imo, no, degredation doesn't really happen the way it would in the cassette duping example, but neither does dna copy bit for bit. mainly because it isn't being copied. that would be cloning (which if memory serves dna does degrade with each serial clone). but adding two different stocks together to form one unique person benefits greatly from more dominant dna and the ability to ignore recessive traits.
--
digital dna... could there be a way to make dna as stable as the binary bits of a computer?

four bits on their own seems to be a stable enough system but during the splicing and merging of the parental and maternal code the unique offspring sometimes have anomalies. would making dna binary solve this problem? what about efficiency? if our genome was purged of junk chains would the reduced and purified strings in binary formation be more or less efficient than keeping the old gatc system?

OTOH what about using more than only a pair of nucliecs base pairs, why not have 3 pairs and make our genome even more efficient (once cleaned up). are Purine and Pyrimidine compatible enough to form a third base pair? (or a terciary base pair of adenine and uracil) a base pair that could be used as a backup in case anomolies crop up. the third pair can read off changes.. like a federally mandated universal base pair, an unmodifyable dataset of everything "human".
----
if anything would noticeable suffer from expression of recessive traits or other forms of damaged dna then it would be the brain, the skin, hair, things you can see.

basic systems like digestion, reproduction can be affected but you can live a normal life and hide such defects more easily that splotchy skin or slurred speech.

"Terciary base pair" ... I'm trying to picture this one

There is a difference between a 'loss of genetic information' and 'genetic damage', as well as a systemic loss of such information in an individual that is not passed on to its offspring, and that which is... and yet another set of conditions gives rise to changes in genetic information that is passed on in regards to an entire species (this one is an ongoing process, usually resulting for 'adaptive' reasons and thus the betterment of the species = evolution).

The difference in a loss of genetic information and genetic damage in an individual is this: The cells in your body are always rejuvenating themseves... or rather, they divide and form new cells to replace old ones that die (ie, old skin cells slough off and new ones replace them). This happens through a process called mitosis, at difference rates throughout your body, depending on how actively dividing the cells are (ie, skin cells will divide more rapidly than bone cells). When this happens, the 26 pairs of chromosomes (which equals 46 chromosomes total) line up at the center of the cell like football players at the line of scrimage, and then divide in opposite directions and the cell membrane closes in, in between them and the cell divides into two (Each of the chromosomes has produced an identical counterpart prior to dividing so you end up with 23 pair of chromosomes after the seperation... so for a moment you actually have 46pr of chromosomes).

Now, in before these chromosomes line up to divide, they may be damaged in ways that can or can not be passed on to the daughter cells (damged by processes such as ionizing radiation). In either case, genetic damage has occurred... but in most cases it is of no negative consequence. Without getting too drawn out, if the change is passed on to the daughter cell it has become a mutation.... other types of damage creates a portion of a chromosome that can not be passed on (ie, the chormatid is spliced and the ends attach to itself like a ring, rather than to 'viable' portions of itself or another) and that information in lost. BUT... this only pertains to that particular cell.. .and in the cases where the information was passed, to any future generations of that cell. The reason this is of no consequence to this person's (or other organism's) offspring, is that these cells (those undergoing mitosis as opposed to meiosis) are not germ cells (sperm or egg). Thus, the changes are not passed on. Cellular damage, however, can lead to cancer in the individual. This can also not be passed on of course, and (depending on the age of the effected person and whether they've had children) can lessen the chances of some persons reproducing offspring (ie, the individual dies from its disease or is rendered incapable of reproducing due to reprecussions from his or her treatment).

Now, these same mutations can occur in germ cells (sperm or egg) and can be passed on as well. (That is why, when you get an x-ray taken, they shield your gonads... in addition to the fact that too much radiation can lead to steralization). This does not mean that there was necesarrily a loss of information (though there can be), but that there is a change/mutation. Some of these can adversely affect the offspring, but if the offspring is adversely effected, it lessens its chance of reproducing, and thus lessess the chance of it affecting the larger population due to safeguards set in place by God, called natural selection (scientifically speaking).

[bugmenot]

Originally Posted by EWright

Some of these can adversely affect the offspring, but if the offspring is adversely effected, it lessens its chance of reproducing, and thus lessess the chance of it affecting the larger population due to safeguards set in place by God, called natural selection (scientifically speaking).

That's the problem these days. Natural selection no longer happens. Everybody gets to reproduce and have offspring. The weak out number the strong. In the past the sick and the weak died off thus bettering the species by allowing only the strong to reproduce and pass on stronger traits.
Does natural selection still apply to humans? I think it does not.

[Turtle]

Originally Posted by bugmenot

That's the problem these days. Natural selection no longer happens. Everybody gets to reproduce and have offspring. The weak out number the strong. In the past the sick and the weak died off thus bettering the species by allowing only the strong to reproduce and pass on stronger traits.

___I think the archeological evidence clearly shows the sick & weak were cared for by their groups/tribes in the ancient past. Skeletons showing crippling injuries & surgeries long healed before death aren't uncommon. We are a "better" species precisely because we care for our sick & feeble. It is natural, & we select it.

[EWright]

Originally Posted by bugmenot

That's the problem these days. Natural selection no longer happens. Everybody gets to reproduce and have offspring. The weak out number the strong. In the past the sick and the weak died off thus bettering the species by allowing only the strong to reproduce and pass on stronger traits.
Does natural selection still apply to humans? I think it does not.

Those with the most significant biological defects are less likely to breed, thus natural selection still exists. I would say that natural selection in humans is undergoing a course that will be primarily based on a combination of intellect and physical attributes. The course of this type of selection may be slowed, however, by the fact that intellectuals *tend* to produce fewer offspring. However, these offspring are presumably, in most cases, better cared for. But there's still a lot of stupid, ignorant and unattractive people with nothing better to do than to make a bunch of babies. But hopefully it just means it will take longer to naturally weed out them out of the gene pool.

[Turtle]

___..."most significant" & "less likely" express far too general a situation to scientifically substantate a conclusion.
___We humans still don't understand our own nature, so conclusions on what is valuable for later selection have no strong basis in fact. No end of great intellects were "ugly", bad-tempered, or ill-kempt. The principle of emergence, by its very definition, is reason enough not to judge the value of a human being.
___I do think natural selection is at work, but the direction it is taking is an emergent property & therefore unknowable until it is expressed.

[EWright]

Originally Posted by Turtle

___..."most significant" & "less likely" express far too general a situation to scientifically substantate a conclusion.
___We humans still don't understand our own nature, so conclusions on what is valuable for later selection have no strong basis in fact. No end of great intellects were "ugly", bad-tempered, or ill-kempt. The principle of emergence, by its very definition, is reason enough not to judge the value of a human being.
___I do think natural selection is at work, but the direction it is taking is an emergent property & therefore unknowable until it is expressed.

Very likely true. My point was certainly speculative, but I still like it

[Biochemist]

Originally Posted by bugmenot

Do humans lose genetic information as time goes on?....

We certainyl do lose genetic information. Most (and perhaps all) mutations are essentially genetic information losses. The presumption that speciation occurs via sequential mutaion is broadal held, but it is only a presumption. There is no example that credibly demonstrates a mutation resulting in increased information load.

The general case is that most species lose genetic information over time.