What is the significance of this experiment?

[Ouroboros]

No...this is so wrong...I don't even...:run:

I know...

There's no use to explain it. It's beyond...

Just for other people's information: DNA is a double stranded RNA, i.e. RNA*2 = DNA. And the carrier of genes is the DNA, but mRNA is used for polypeptide synthesis (m stands for message, it's a copy).

Adaptation to climate is many times a matter of an ability our body has to adjust, not a change of DNA or RNA. It's a change of hormones, chemicals, nutrients, etc. Not gene code.

Here's an interesting fact, 3-stranded DNAs have been found. DNA with 3 RNA strings. Very rare. I guess the proper acronym would be TNA for those.

 

[BioStudent]

Just for other people's information: DNA is a double stranded RNA, i.e. RNA*2 = DNA.

Not to nitpick, while thats close to true, the 'D' in DNA and 'R' in RNA actually denote a difference in structure, so the DNA and RNA molecules are actually different. There is such a thing as double stranded RNA (dsRNA, some viruses use it), but it is structurally different from DNA. In terms of how thay are used by organisms, they are pretty similar.... most use only DNA, though.

Here's an interesting fact, 3-stranded DNAs have been found. DNA with 3 RNA strings. Very rare. I guess the proper acronym would be TNA for those.

Yeah, triple-stranded DNA is very cool, and is actually thought to occasionally be used by organisms to regulate gene function (the mechanism controlling the "adaptation" you described in your post). Not many genes are regulated this way, but at least one is thought to be. It has no cool acronym, though, none I could find

 

[johnhanks]

Just for other people's information: DNA is a double stranded RNA, i.e. RNA*2 = DNA.

Not so, I'm afraid. RNA is usually single stranded, it's true, and DNA almost always double; but RNA contains the sugar ribose instead of deoxyribose (hence the initials) and one of the bases is different (uracil instead of thymine).

 

[Ouroboros]

Not to nitpick, while thats close to true, the 'D' in DNA and 'R' in RNA actually denote a difference in structure, so the DNA and RNA molecules are actually different. There is such a thing as double stranded RNA (dsRNA, some viruses use it), but it is structurally different from DNA. In terms of how thay are used by organisms, they are pretty similar.... most use only DNA, though.

Fair enough.

You're right, they're not exactly the same. It was a response (simplified) to Sculelos very strange claims earlier. I have no interest in debating him, but at least point out some parts that are really off the charts.

Btw, great to have you here, and I'm glad the path of career you picked. We need more people like you and in the field of biology/genetics etc.

Yeah, triple-stranded DNA is very cool, and is actually thought to occasionally be used by organisms to regulate gene function (the mechanism controlling the "adaptation" you described in your post). Not many genes are regulated this way, but at least one is thought to be. It has no cool acronym, though, none I could find

I was suggesting TNA since there might be a "tri" in there somewhere.

 

[Ouroboros]

Not so, I'm afraid. RNA is usually single stranded, it's true, and DNA almost always double; but RNA contains the sugar ribose instead of deoxyribose (hence the initials) and one of the bases is different (uracil instead of thymine).

True.

My point was too simplified. What I wanted to point out is that RNA isn't the carrier of the genes, but the DNA is, and DNA is a double strand of chains of nucleotides. RNA is a single strand of nucleotides. And it's true that RNA has uracil instead of thymine in DNA, but the basic structure is the same for the strands. And the main (and simplified) difference is that DNA has two, RNA has only one.

Sculelos claims where that RNA mutates according to adaptations to environment, or something like that. But in our cells, RNA are only temporary tools, not the actual gene storage. DNA is the part that would carry any mutations, and there's a difference between just adaptations and mutations. His claims were very confusing and I wanted to bring up a dialogue where some of the errors were pointed out.

 

[BioStudent]

Sculelos claims where that RNA mutates according to adaptations to environment, or something like that. But in our cells, RNA are only temporary tools, not the actual gene storage. DNA is the part that would carry any mutations, and there's a difference between just adaptations and mutations. His claims were very confusing and I wanted to bring up a dialogue where some of the errors were pointed out.

I'll gladly join in that dialogue. RNA as such is also not passed down from parents to offspring. It simply does not exist for long enough for that to happen. For this reason, RNA changes cannot cause change over several generations, only DNA can.

In addition, RNA can never be incorporated into DNA, since they are structurally different and speak different "languages" (use uracil instead of thymine).

Also, "recessive" and "dominant" are traits of genes, which are encoded by DNA, not RNA.

The only part that was actually correct to any degree was the implication that the environment affects an organism's traits without changes in the DNA sequence; this is what the branch of biology called epigenetics studies. That said, epigenetics has nothing to do with changes in RNA sequence or anything like that. I could try to explain the some of the mechanisms if anyone wants me to, but I don't want to turn this thread into a lecture.... I'm just a student, I'm supposed to listen to lectures, not give them

 

[Ouroboros]

I'll gladly join in that dialogue. RNA as such is also not passed down from parents to offspring. It simply does not exist for long enough for that to happen. For this reason, RNA changes cannot cause change over several generations, only DNA can.

Exactly. That's what I was trying to get to.

In addition, RNA can never be incorporated into DNA, since they are structurally different and speak different "languages" (use uracil instead of thymine).

Also, "recessive" and "dominant" are traits of genes, which are encoded by DNA, not RNA.

The only part that was actually correct to any degree was the implication that the environment affects an organism's traits without changes in the DNA sequence; this is what the branch of biology called epigenetics studies.

Yes. I've heard about the epigenetics. It's a fairly new science in my understanding, but it makes sense. There are more things that are transferred to the offspring besides the DNA. After all, a person's existence begin with an ova and a sperm, not just the DNA. There are many other parts to the cell that are inherited from get-go, and also nutrition/diet while gestating.

That said, epigenetics has nothing to do with changes in RNA sequence or anything like that. I could try to explain the some of the mechanisms if anyone wants me to, but I don't want to turn this thread into a lecture.... I'm just a student, I'm supposed to listen to lectures, not give them

I understand.

 

[johnhanks]

My point was too simplified. What I wanted to point out is that RNA isn't the carrier of the genes, but the DNA is, and DNA is a double strand of chains of nucleotides. RNA is a single strand of nucleotides. And it's true that RNA has uracil instead of thymine in DNA, but the basic structure is the same for the strands. And the main (and simplified) difference is that DNA has two, RNA has only one.

Well, double-stranded RNA does exist (and parts of the tRNA molecule are base-paired); so does single-stranded DNA. But I won't nit-pick beyond that. Your point that DNA is what transmits information between generations is the important one.

Sculelos claims ...

I tune out at that point.

 

[lewisnotmiller]

How can a wolf give birth to a chihuahua?

Less painfully than a chihuahua gives birth to a wolf?

 

[BioStudent]

Less painfully than a chihuahua gives birth to a wolf?

haha

 

[Man of Faith]

50,000 generations of e.coli and they are still e.coli. That tells me something.

 

[secret2]

50,000 generations of e.coli and they are still e.coli. That tells me something.

That also tells us something. That you, along with most other evolution deniers on this forum, have zero knowledge in the concept of "SPECIES".

 

[Man of Faith]

That also tells us something. That you, along with most other evolution deniers on this forum, have zero knowledge in the concept of "SPECIES".

Maybe one day if you can overcome your bias that creationists are uneducated and stupid then you can understand the concepts that I am talking about and realize the evolution is all smoke and mirrors based on a naturalistic philosophy and forced acceptance.

There isn't any universally accepted definition of species, so the word species means nothing by itself. Speciation doesn't equate to Darwinian evolution anymore than kind does. Microevolution and macroevolution are universally accepted now, when even a few years back it was denied by evolutionists. That is actually devastating to evolution because according to evolution, there is only time and given enough time anything is possible, but we don't see that in reality. We see microevolution and no macroevolution, even in the fossil record.

 

[BioStudent]

50,000 generations of e.coli and they are still e.coli. That tells me something.

Well, speciation tends to happen much faster when a population is exposed to a variety of environments or stress conditions. Like when an ancestral ape population could live in woodland or savannah, and the two different environments led to one species becoming two (proto-chimps and proto-humans, respectively).

The bacteria in the experiment are all living under the same conditions that they were in the beginning, they are just in forced isolation from each other. They have adapted slightly, but my guess is, because the conditions are well suited to their growth, the populations are changing rather slowly, because the average cell is well suited to the enviroment. Most mutations that arise are either harmful, or not beneficial enough that they spread widely through the population. Very rarely, some mutation that is really beneficial comes along, and that does spread quickly and become the new norm (like the citrate transport mutation). Due to the rarity of this, the bacteria stay very similar to the founding population.

Now, if they were to radically change some conditions, like make the environment hotter and more acidic or something, only a small part of the population would survive (those that aren't average are the ones that survive), and that population would be much more different from the original after 50,000 generations than the ones they have now, because a whole host of adaptations would be needed for the bacteria to be well suited to growing in the new conditions (not just survive, but survive well).

Anyways, 50,000 generations isn't that many in evolutionary terms. Many animals can breed when they are 1-2 years old, so 50,000 generations is only 50,000 to 100,000 years.... life has had billions of years to evolve.

 

[Yerda]

50,000 generations of e.coli and they are still e.coli. That tells me something.

To be fair there have been a hell of a lot of generations from the first E.coli to the ones living in your gut right now. Neither fact really tells us much beyond the possibility that E.coli, like other bacteria, are exquisitely adapted to the niche they fill.

 

[BioStudent]

To be fair there have been a hell of a lot of generations from the first E.coli to the ones living in your gut right now. Neither fact really tells us much beyond the possibility that E.coli, like other bacteria, are exquisitely adapted to the niche they fill.

Exactly! Added to the fact that, with bactria, species was such a nebulous concept from the beginnig...

 

[philbo]

The only part that was actually correct to any degree was the implication that the environment affects an organism's traits without changes in the DNA sequence; this is what the branch of biology called epigenetics studies. That said, epigenetics has nothing to do with changes in RNA sequence or anything like that. I could try to explain the some of the mechanisms if anyone wants me to, but I don't want to turn this thread into a lecture.... I'm just a student, I'm supposed to listen to lectures, not give them

Ah, but explaining what you think you know is an excellent way to see how well you understand it

Epigenetics is one of those new disciplines since I did my degree (an inordinate length of time ago), and, for me at least, was a bit of a "well, duh.. why didn't we realize that already" sort of feeling. You know - it's crystal clear with 100% hindsight When they (who knows, that could be "you" rather than "they") get all the mechanisms worked out, we'll know a shedload more about inheritance & why we are exactly what we are.