Let's start at the beginning? maybe?

[Pogo]

I know this may sound like a silly question, but thank you for putting up with me, here is the question -- gene pool is that which is within each individual. (Right?)

Not a silly question, part of an at times confusing vocabulary.
gene is a part of your DNA that is inherited and connected to a trait.
Genome is the collection of all the genes/genetic material in an individual or if referring to a group confusingly, all the genetic material for the group as in human genome.
Gene pool is the genetic material of the group not the individual.

 

[Pogo]

Here is a definition of gene pool: "What is a gene pool simple definition?
Definition. 00:00. A gene pool refers to the combination of all the genes (including alleles) present in a reproducing population or species. A large gene pool has extensive genomic diversity and is better able to withstand environmental challenges."
So then the "gene pool" extends to organisms of a reproducing population or species. Gene Pool.
It further goes on to say "Inbreeding contributes to a smaller gene pool, making populations or species less able to adapt and survive when faced with environmental challenges." Not that I understand that, so I'm about ready to give up. And that may be why I am glad, in a sense, I am no longer in a class I pay for (higher education) that I have NO REAL IDEA what they're talking about as the instructor continues on. So you may want to excuse me and I'm excusing myself, I think, at this point, to understand what is meant by a gene pool.
So far I understand it as the genetics within a group that would enable individuals to reproduce.

It is not that the gene pool enables a population to reproduce, the gene pool is the collection of genes and their variants (alleles) such as for blue or brown eyes that belong to a reproducing population. Inbreeding is repeated reproduction with close relationships that cuts down on genetic diversity and allow harmful alleles to flourish. Example being hemophilia in some European royal families.

 

[Pogo]

Sorry, no.

The relationship between individual organisms and gene pools is that of a specimen towards its collective of other biologically compatible specimens - and potential rivals for same, of course.

Individuals have genetic compositions of their own, and they contribute to collective gene pools along with many other individuals. Individuals may (and do) take part of gene pools, and they are in a sense "built" out of elements of gene pools, but they do not have whole gene pools in themselves, because they are individuals. Gene pools are groups.


Allow me to illustrate with this picture (Source: Mechanisms of Evolution | OpenStax: Concepts of Biology | Study Guides )

Each marble represents a specimen, an individual. Each shade or hue of color represents a whole specific genetic composition.

While this picture does not convey that very well, each individual / marble except perhaps for identical twins will have some measure of variation of color / genetic composition from every other marble / individual.

In this illustration, the interior of the bottle represents a certain gene pool before some sort of bottleneck event greatly diminished the population available for potential mating. Perhaps grave famine, or some deadly epidemic, or very intense predation by other lifeforms.

After that event, the surviving population is much diminished, and so is the gene pool. It is not just that there are less specimens, but also that the potential genetic diversity among that population is much lesser than in the previous gene pool; there are less colors and less hues present (the brighter red marbles did not make it to the glass).

Those red marbles represent a certain amount of genetic diversity that was lost due to the bottleneck event.

I like how you ignored the biggest supposed bottleneck in mythology and the inbreeding that would have resulted.

 

[LuisDantas]

I like how you ignored the biggest supposed bottleneck in mythology and the inbreeding that would have resulted.

It was not a conscious decision. It took me a second to realize what you meant.

In any case, that is not really what we are talking about in this thread.

 

[YoursTrue]

Sort of. Most of the time that is accurate. But speciation does occur, which means that sometimes enough genetic variation will accumulate to start to hint of a new species. That will of course affect the ability of the individuals to interbreed with each other.

It is both a rare occurrence and an almost unavoidable one. It will occurr with us humans too, provided that we survive for enough new generations and do not artificially avoid it with some form of genetic screening.







It once did, on its fringes, yes. About 55 thousand years ago. Most living humans have some amount of Neanderthal ancestry.

Of course, that means that the genetic material that we inherited from our Neanderthal ancestors is fully integrated into our own genes and gene pools; it originated in Neanderthals, but it is now as much a part of Homo Sapiens as any other.

To put it in other words, they are not Neanderthal genes in Homo Sapiens; they are Homo Sapiens genes that were acquired from Neanderthal ancestry. They became part of Homo Sapiens' genetic composition by being reliably transmitted from each generation of Homo Sapiens to the next.

I don't know what is known of Denisovan participation in our genetic material. A very quick search suggests that none are known.

About the gene pool for the Neandertals, the "gene pool" for humans is found where and how is it analyzed? P.S. Thank you for keeping the topic down to gene pool description. I appreciate that.

 

[LuisDantas]

Gene pools are an immediate thing. It is not very easy to study millennia later.
The genetic compositions of.specimens, those can be studied

 

[YoursTrue]

@LuisDantas OK, so I have been doing some reading about ancient DNA and Neanderthals and find it hard to understand. I'm not saying you can help me, and I certainly thank you for trying. Because it really does get for me hard to understand. But here's what it says: "Most human sequences differ from each other by an average of 8.0 substitutions, while the human and chimpanzee sequences differ by about 55.0 substitutions. The Neanderthal and modern human sequences differed by approximately 27.2 substitutions." So I'm ready to give up because I can't even know what they mean by "most human sequences differ from each other, etc." By an average of 8.0 substitutions. 8.0 substitutions? What does that mean? So most likely it's a losing prospect to educate me on these things although it would be nice but I think it's beyond my ken right now. All I can say is thanks for trying. Ancient DNA and Neanderthals.

 

[YoursTrue]

Gene pools are an immediate thing. It is not very easy to study millennia later.
The genetic compositions of.specimens, those can be studied

Gene pools are those genes within a population of organisms that can interbreed? I understand if I cannot be taught right now, maybe it's my brain.

 

[YoursTrue]

Gene pools are an immediate thing. It is not very easy to study millennia later.
The genetic compositions of.specimens, those can be studied

So I read that a bone was ground up and analyzed for the genetic content of supposedly a bone to discover I guess the dna content. Ancient DNA and Neanderthals.
But that "gene pool" (Neanderthal) is no longer available for reproduction, is that right?

 

[YoursTrue]

It is not that the gene pool enables a population to reproduce, the gene pool is the collection of genes and their variants (alleles) such as for blue or brown eyes that belong to a reproducing population. Inbreeding is repeated reproduction with close relationships that cuts down on genetic diversity and allow harmful alleles to flourish. Example being hemophilia in some European royal families.

I give up.

 

[Subduction Zone]

So I read that a bone was ground up and analyzed for the genetic content of supposedly a bone to discover I guess the dna content. Ancient DNA and Neanderthals.
But that "gene pool" (Neanderthal) is no longer available for reproduction, is that right?

That article is about mitochondrial DNA, that is the DNA within mitochondria. You have heard of mitochondrial Eve, Mitochondrial DNA is as the name tells you the DNA found within the mitochondria of our cells. It is useful in all sorts of ways. Number one it is far shorter than Nuclear DNA. Human nuclear DNA, the DNA that made you into you, Your nuclear DNA is roughly 3 billion base pairs long. The mitochondria in your cells have a much smaller number of base pairs. Only 16,569. It also evolves at a higher rate. But because it is so short, comparatively, the number of changes will be rathe small, as in the figures that you gave.

At first I did not understand how you could have such small numbers, but then it all made sense when it was the much shorter mtDNA that you were talking about.

At any rate because it is so much shorter it is far easier to sequence and understand a genome only 16,569 base pares long rather than one roughly 200,000 times longer. Individual mutations are far easier to identify and track too.

Mitochondrial DNA - Wikipedia

en.wikipedia.org

When it comes to whole genome percentages of difference have to be used rather than number of substitutions:

Neanderthal Genome Sequenced

Researchers have produced the first whole-genome sequence of the Neanderthal genome. The analysis provides the first genome-wide look at the similarities and differences of the closest evolutionary relative to humans.

www.nih.gov

That article only involves the nuclear DNA of three Neanderthal females. One quote out of that article concerns me a bit. It is this:

"The analysis, which appeared in the May 7, 2010, issue of Science, shows that Neanderthal DNA is 99.7% identical to present-day human DNA and 98.8% identical to chimpanzee DNA. Present-day human DNA is also 98.8% identical to chimpanzee. The comparison produced a catalog of genetic differences that allowed the researchers to identify features unique to present-day humans. Many regions of the Neanderthal genome, they found, are more like those of the chimpanzee than present-day humans."

I wonder if they used the same metric. That seems unlikely to me since that difference is too great considering how short of a time ago that they separated from humans. If they are using different metrics there is not point in comparing the two numbers. For example a reasonable metric to use between chimps and humans would be to compare coding DNA only. That can be thought of as the "active DNA" the DNA that goes into making us individual. The noncoding DNA still can have a function, though not all of it does, but it does not change the end product noticeably. The number that they have for humans and Neanderthals may be whole genome comparison. Since the noncoding DNA is not nearly as important it can freely mutate at a higher rate than the coding DNA.

 

[LuisDantas]

@LuisDantas OK, so I have been doing some reading about ancient DNA and Neanderthals and find it hard to understand. I'm not saying you can help me, and I certainly thank you for trying. Because it really does get for me hard to understand. But here's what it says: "Most human sequences differ from each other by an average of 8.0 substitutions, while the human and chimpanzee sequences differ by about 55.0 substitutions. The Neanderthal and modern human sequences differed by approximately 27.2 substitutions." So I'm ready to give up because I can't even know what they mean by "most human sequences differ from each other, etc." By an average of 8.0 substitutions. 8.0 substitutions? What does that mean? So most likely it's a losing prospect to educate me on these things although it would be nice but I think it's beyond my ken right now. All I can say is thanks for trying. Ancient DNA and Neanderthals.

All humans have genetic material in each of our cells. That genetic material is fairly constant within any given person, but other persons will have similar yet different genetic material. The molecules themselves are not too different, but they are arranged differently, resulting in different people - different metabolisms, skin and eye tones, skeleton details, etc. The cell building processes are respond to those arrangements in ways that are often rather complex and not entirely understood ("mapped").

But the genetic material itself is not too difficult to examine, nor to compare with those of other people. That is why DNA tests have become so widespread.

Sexual reproduction involves mixing DNA strands from both biological parents, which means that the offspring will not be genetically identical to either parent.

Clones or identical twins would be genetically identical (with some provisos that are best not discussed right now). Some plants, such as bananas, are in fact unable to reproduce sexually and are cultivated basically by cloning, meaning that there is very little genetic diversity in each banana variety. In effect, they have no gene pool.

But for humans the situation is very different indeed. Because we reproduce sexually, our genetic composition varies considerably. Each human being has its own DNA with its own genetic combinations ("genetic information"), which decisively orient the building of our cells and organs. And it is possible to compare that genetic information with that of other human beings and quantify the levels of divergence. The same can also be made between human genetic information and that of other primates and, indeed, any other biological cells.

Gene pools are those genes within a population of organisms that can interbreed? I understand if I cannot be taught right now, maybe it's my brain.

Gene pools are the populations themselves. They are the groups of fertile beings that are fairly accessible to each other across time and space.

They are not individual beings and they are not contained within individual beings; on the contrary, they are composed of individuals, albeit with a focus on their genetic material.

So I read that a bone was ground up and analyzed for the genetic content of supposedly a bone to discover I guess the dna content. Ancient DNA and Neanderthals.

Correct. Bones have cell tissues that can be studied in order to at least attempt to read their genetic material.

Of course, they will not necessarily be well preserved enough for that reading to be possible.

But that "gene pool" (Neanderthal) is no longer available for reproduction, is that right?

Yes, because there are no living and fertile Neanderthals around.

 

[Subduction Zone]

All humans have genetic material in each of our cells. That genetic material is fairly constant within any given person, but other persons will have similar yet different genetic material. The molecules themselves are not too different, but they are arranged differently, resulting in different people - different metabolisms, skin and eye tones, skeleton details, etc. The cell building processes are respond to those arrangements in ways that are often rather complex and not entirely understood ("mapped").

But the genetic material itself is not too difficult to examine, nor to compare with those of other people. That is why DNA tests have become so widespread.

Sexual reproduction involves mixing DNA strands from both biological parents, which means that the offspring will not be genetically identical to either parent.

Clones or identical twins would be genetically identical (with some provisos that are best not discussed right now). Some plants, such as bananas, are in fact unable to reproduce sexually and are cultivated basically by cloning, meaning that there is very little genetic diversity in each banana variety. In effect, they have no gene pool.

But for humans the situation is very different indeed. Because we reproduce sexually, our genetic composition varies considerably. Each human being has its own DNA with its own genetic combinations ("genetic information"), which decisively orient the building of our cells and organs. And it is possible to compare that genetic information with that of other human beings and quantify the levels of divergence. The same can also be made between human genetic information and that of other primates and, indeed, any other biological cells.




Gene pools are the populations themselves. They are the groups of fertile beings that are fairly accessible to each other across time and space.

They are not individual beings and they are not contained within individual beings; on the contrary, they are composed of individuals, albeit with a focus on their genetic material.




Correct. Bones have cell tissues that can be studied in order to at least attempt to read their genetic material.

Of course, they will not necessarily be well preserved enough for that reading to be possible.



Yes, because there are no living and fertile Neanderthals around.

To save you from reading my long post the DNA she was talking about was mitochondrial DNA, not nuclear DNA. That explains the very low number of changes. Though mtDNA has a higher evolution rate it is roughly 1/200,000th of the length of nuclear DNA so changes in the millions become changes in single to double digits in the much shorter mtDNA.

 

[Heyo]

But that "gene pool" (Neanderthal) is no longer available for reproduction, is that right?

Yes, it is. I think you got it, the gene pool is always only a snapshot. It is constantly changing.
And it is dependent on circumstances. The gene pool of an island population is different from the gene pool of the whole species.

Now, how to get the "gene pool"?
Round up all the individuals of the population you want the gene pool off. Take their DNA. Add up all the genes of all the individuals DNAs. (I.e. only different genes or alleles count.)

Suppose an individual gets born tomorrow with a mutation that nobody else has. The gene pool is then bigger (by that one mutation).

When an individual dies, who had a gene, that nobody else had, the gene pool gets smaller (by that one gene).

Birth or death of individuals, who don't have unique genes, don't change the gene pool.

 

[Balthazzar]

Gene pool = Total living of any specific species

 

[YoursTrue]

Yes, it is. I think you got it, the gene pool is always only a snapshot. It is constantly changing.
And it is dependent on circumstances. The gene pool of an island population is different from the gene pool of the whole species.

Now, how to get the "gene pool"?
Round up all the individuals of the population you want the gene pool off. Take their DNA. Add up all the genes of all the individuals DNAs. (I.e. only different genes or alleles count.)

Suppose an individual gets born tomorrow with a mutation that nobody else has. The gene pool is then bigger (by that one mutation).

When an individual dies, who had a gene, that nobody else had, the gene pool gets smaller (by that one gene).

Birth or death of individuals, who don't have unique genes, don't change the gene pool.

Maybe the term gene pool is not a good one, because I do not understand. So...I think I'm giving up on understanding it.

 

[YoursTrue]

Gene pool = Total living of any specific species

ok, that makes more sense to me. although there are questions. But maybe I'll leave it at that until I understand more.

 

[LuisDantas]

Gene pool = Total living of any specific species

At a given time and place, you mean?

 

[YoursTrue]

Yes, it is. I think you got it, the gene pool is always only a snapshot. It is constantly changing.
And it is dependent on circumstances. The gene pool of an island population is different from the gene pool of the whole species.

Now, how to get the "gene pool"?
Round up all the individuals of the population you want the gene pool off. Take their DNA. Add up all the genes of all the individuals DNAs. (I.e. only different genes or alleles count.)

Suppose an individual gets born tomorrow with a mutation that nobody else has. The gene pool is then bigger (by that one mutation).

When an individual dies, who had a gene, that nobody else had, the gene pool gets smaller (by that one gene).

So the question now is about those said hominids(?) that came before homosapiens, and which are now extinct. OK, let me guess -- all the hominids that supposedly came before homosapiens are extinct...?

 

[YoursTrue]

All humans have genetic material in each of our cells.

OK, I believe that.

That genetic material is fairly constant within any given person, but other persons will have similar yet different genetic material.

All right. Realizing this is not a scientific treatise right now, I have to say that I do not understand what is meant by "that genetic material is fairly constant within any given person." (Fairly constant? You mean it can change within a person?) I think I'll stop there.