Darwin re-visited

[Michaelangelica]

I’m familiar with this idea under the broad term ”epigenetics”.

Yes he uses this term which goes back to Aristotle !

 

About ten years ago, it was pretty controversial.

probably still is. His book was published in 2001. i have another book on Darwin published in 2001 which says

"the genetic material is constant ('hard"); it cannot be changed by the environment or by use and disuse of the phenotype. The inheritance of constant genetic material is called hard inheritance. genes cannot be modified by the environment. Properties acquired by the proteins of the phenotype cannot be transmitted to the nucleic acids of the germ cells. There is no inheritance of acquired characteristics"

From p91 "What Evolution Is"Ernst Mayr

Moore gives the example of the Galapagos woodpecker finch. . .it is famous for using a tool- a twig or a cactus spine- which it holds in its beak to poke out grubs from the barks of trees. . .Probably its novel behaviour is based on learning rather than gene mutations. . .One apparent result is that these birds have never evolved the typical beak or the typical tongue of other woodpeckers. Why not?

I think he then proposes an environmental/gene/learning/society interaction that selects for tool using skills. The birds have co-evolved with aspects of their environment. these skills can be "passed on" and that Darwin's (and (Lamarck's?) conviction that acquired characteristics can be inherited was well founded in the first place

He talks a bit about "Canalization" where one imagines a ball rolling down a valley. As the ball travels down the valley it can move in different directions even sometimes jump to another valley.

Moore gives the example of mallard ducklings attraction to the 'assembly call" of their mothers. Although ducklings that hear these sounds as embryos always develop a preference for the mallard maternal call, mallard embryos that are prevented from hearing these sounds grow to be attracted to other species' maternal calls as they are to their own

Gottlieb found that he could induce mallard ducklings to prefer the sound of a chicken by allowing them exposure only to these sounds (whilst in the egg.

Most interestingly however he discovered that mallard embryos exposed to BOTH the chicken and the mallard call preferred the mallard call when hatched.

While the development of the mallard call is highly canalised it is not exclusively controlled by the genes.

Instead an experience can serve to shield development some traits are exquisitely sensitive to environmental factors others are impervious.

 

The last time I vacationed with them, I enjoyed a good “I told you so”

It's a great feeling; even if a little uncharitable!:cup:

 

A lot of scientific resistance to it was, I think, wishful thinking. The idea that traits were fully determined, combined with advances in automated gene sequencing and computer “bioinformatics”, promised to fully explain functional biology within people’s lifetimes. It’s understandable that people were reluctant to give it up until evidence undeniably demanded it.

We still have a lot of bio-technology hype. The reality is far more complex.

 

I

f Moore is claiming that genetic determinism explains no traits, however, I think he’s going too far.

No he's not just a very complex and yet to be understood interaction.

Interestingly in the notes at the back of the book he quotes research of Steele, Lindley and Blanden (1193) who say "current molecular knowledge of the immune system to show that there is scientific evidence consistent with the inheritance of acquired characteristics"

So I gather from this that not only learning but DNA type transmission of traits is proposed. Move over Lamarck!

I need to read some of their work to see what they are on about

 

I wonder if Mendel was able to remove himself from his monastery garden and grow some of his peas in the Highlands of New guinea or Outback Australia weather we would have a different view of the inheritance of acquired characteristics??

 

An annoying , but sometimes insightful, book I am also reading "Life's Grandeur" by S J Gould says

"Why can't organisms figure out what would do them good, develop those adaptive features by dint of effort during their lifetimes, and then pass on those improvements to their offspring in the form of altered hereditary? We call such a putative mechanism"Lamarckism" or the"inheritance of acquired characteristics" Natural evolution would go like gangbusters if hereditary happened to work in this manner" p221

 

Developmentalists like Moore don't seem to want to make a difference between learned and genetic traits. So "gangbusters" it is!?

 

--

Michael

[Michaelangelica]

DARWIN'S FINCHES EVOLVING FAST (Environment & Nature News, 17/7/06) A Galapagos finch that helped reveal the origins of species to Charles Darwin has now undergone a spurt of rapid climate-driven evolution, biologists report.

http://abc.net.au/science/news/stories/s1688507.htm

 

 

"Environmental changes severe enough to cause sharp population declines, as seen with the finches, are also selection events."

 

As more and more species undergo the stresses of climate change, more cases of rapid evolution can be expected, Skelly says.

 

It's not likely to save most species facing the climatic bottleneck, of course, but it does give a few a fighting chance, he explains.

[Michaelangelica]

What do people know about "Genetic Clocks" ?

 

Virtually all the non-coding mutations are neutral

Even in the genes that code for proteins, many mutations are 'silent'

 

How do we have 'copy errors' when it is said RNA is rarely "wrong'

 

Is there a constant rate of mutation?

If so why? (and what is it?)

 

Should "natural selection" apply to traits?

or only to the emergence of a new species?

 

What has happened to the human DNA in the last 100,000 years?

Enough to call us a new species?

[Michaelangelica]

This is not Natural Selection as we know it

 

Toxic venom of brown spiders

 

http://www.abc.net.au/rn/scienceshow/stories/2006/1718464.htm

Brown spiders in the United States cause skin ulcers due to a single toxic venom. It's known that some toxins produced by bacteria and the spider toxin are related. So genetic material had to be transferred at some stage.

It's most likely to have gone from the spiders to the bacteria. Matthew Cordes is looking for the mechanism, by which the gene was transferred.

A clue could be the flies of farm animal which are prey for spiders. The poison's dual origins may help in the development of treatment for spider bite.

Guests

 

Matthew Cordes

Assistant professor Biochemistry & molecular biophysics University of Arizona Tuscon Arizona

[Michaelangelica]

Beam me up Scotty

This is not natural Selection either

Is it?

Proteins and energy flow in plant cells

 

Listen Now - 19082006 | Download Audio - 19082006

 

Chloroplasts and mitochondria are two of the important organelles found within plant cells. They can be seen as cells within cells. Harvey Millar is part of an international race to locate the 30,000 proteins found in plant cells. So far 4,000 have been identified and located. This information will help us understand the energy flow which takes place in plants.

 

Show Transcript | Hide Transcript

Transcript

 

Robyn Williams: First in this Science Show, those micro-machines. And you are full of them, couldn't live without their industrious help, little germs that came to stay. Understanding how they work could revolutionise how we use plants. This is Professor Harvey Millar of the University of Western Australia.

 

Harvey Millar: How they got in of course is an interesting question that nobody can really resolve. There are various ideas, but effectively the idea was that they were free-living organisms which invaded the cell and this was the process in which plant cells, and in fact even our cells, actually gained all the little substructures inside them; ex-little bacteria, basically, that invaded. And after they invaded they sort of set up house, stayed there, and slowly transferred all of their genetic information into the nucleus, all but a little bit. So they're effectively become permanent residents because you can't go back when you've given away your DNA, so you're reliant on the cell to actually provide all those proteins that go to that location.

 

Robyn Williams: In the same way that we can illustrate that the corals have got algae living in them, doing a particular job, so presumably these previous mitochondria and previous chloroplasts were doing some other job in the outside and invaded not necessarily a great big body but a big cell...

 

Harvey Millar: It invaded another individual cell, so it happened really at a single cellular stage, that invasion, even more so than the corals because the corals is two cells living together whereas this is really one cell living inside another cell, which is really a fundamental difference. And in the case of coral, that relationship can break down, whereas in these situations it's a life-long commitment.

Lots more here:

http://www.abc.net.au/rn/scienceshow/stories/2006/1718412.htm#

[Michaelangelica]

If natural selection can work in any direction; where do the genes come from for older species/behaviour?

The Junk DNA?

What causes the expression of genes that have not been expressed for eons?

 

Reverse evolution would occur when genes recently acquired through evolution are lost again, or when genes become reactivated after falling into disuse.

 

Tan has gone as far as to propose that the “reverse evolution” of the family in Turkey affects the mind as well as the body, noting that victims of the syndrome are retarded. Crandall said he doesn’t buy many of Tan’s ideas, but that at least with regard to walking, Tan may have suggested a concept worth testing.

 

Scientific doubts on reverse evolution, Crandall wrote, have nothing to do with a popular misconception that evolution “has no direction.” It does to some extent, he argued—species tend to become better suited to their environment—and that may be irrelevant anyway, since a return to an ancestral state can occur whether or not one thinks of evolution as directed.

 

“I don’t know of any evolutionary biologists who would subscribe to the notion that reverse evolution is impossible,” Crandall wrote. “It doesn’t take long in evolutionary biology to figure out that nothing is impossible!”

* * *

http://www.world-science.net/exclusives/060306_reversfrm.htm

[ughaibu]

Endosymbiosis doesn't conflict with natural selection, neither do viral theories.

[Michaelangelica]

In the past decade, researchers have discovered that Tibetan villagers living in altitudes of over 4,000 M are genetically adapted to do so.

 

At least one extra gene helps their blood cells bind more oxygen, and also appears to boost their reproductive fitness under low-oxygen conditions.

 

Within the past 10,000 years or so, these Tibetans have evolved genetically to be adapted to their environment.

 

SOURCE"Big Ideas in Science" ed H. Swain JC Lon. 2002

 

Questions:-

1)Isn't this too quick for Natural Selection?

 

2) Do they really mean "extra gene"?

If so, where did it come from?

 

3)Could the extreme climatic conditions forced the expression of genetic material already available to all of us?

[Michaelangelica]

This was sort of interesting and maybe relevant

Only 20-50% of us is due to genes.

.

Leaves a lot for the environment does it not?

 

So can the learned environment be passed on as genetic information is.

Is what we learn as important as our chromosomes?

Is this relevant to Natural Selection?

http://www.abc.net.au/science/news/stories/2006/1732152.htm

Party animal? Don't blame your genes

Jennifer Viegas

Discovery News

Tuesday, 5 September 2006

 

Genes shape our health and appearance more than they shape our personality, suggests a new study of thousands of people in a genetically isolated part of the world.

 

According to the study, published in the August issue of PLoS Genetics, genetics account for roughly 51% of a person's height, weight and body shape, 25% of cardiovascular function and about 40% of certain blood characteristics, such as sugar and cholesterol levels.

 

But genes only account for about 19% of many documented personality traits, such as neuroticism, extraversion, agreeableness and conscientiousness.

[Michaelangelica]

http://www.world-science.net/othernews/061012_tiny-genome.htm

 

And

Lynn Margulis (1938-), " In reality, the Tree of life. . .species come together, fuse, and make new beings who start again"

 

Margulis believes that these multiple bacterial unions, which created the first mobile, oxygen-breathing, nucleated cells, took place more than 2 billion yers ago.

[HydrogenBond]

The ability of virus to alter genetics for the bad, suggests that the opposite might also be true. That virus may have also alterred the genetics for the good. By this I do not mean wiping out a range of the population to assure survival of the rest, but adding genetic content to genes which allows progressions in the DNA. This is sort of what the latets science is trying to do but it may also happen naturally.

 

What is sort of interesting is that virus do not just spontaneously appear. They are output products from other lifeforms. This may be food or poison for the DNA. In that sense, a bird may give off a virus that it absorbed by a higher animal, causing the higher animal to gain something useful or become sick. It may not be cooincidence that some of the lowest lifeforms actually contain more DNA than higher lifeforms.

[hallenrm]

Righto Hydrogenbond! It is quite likely that certain kinds of bacteria have evolved that can produce some kinds of virus.

 

By the way here's a news report that says that a team of scientist have developed a kind of virus that can kill certain virus.

 

http://www.nature.com/cgt/journal/v12/n1/abs/7700769a.html

 

And here's another news, now one can access most of the Darwin's original writings online

 

http://darwin-online.org.uk/

 

Isn't that a welcome change!!!

[maikeru]

The ability of virus to alter genetics for the bad, suggests that the opposite might also be true. That virus may have also alterred the genetics for the good. By this I do not mean wiping out a range of the population to assure survival of the rest, but adding genetic content to genes which allows progressions in the DNA. This is sort of what the latets science is trying to do but it may also happen naturally.

 

What is sort of interesting is that virus do not just spontaneously appear. They are output products from other lifeforms. This may be food or poison for the DNA. In that sense, a bird may give off a virus that it absorbed by a higher animal, causing the higher animal to gain something useful or become sick. It may not be cooincidence that some of the lowest lifeforms actually contain more DNA than higher lifeforms.

 

Several viruses, in particular retroviruses, are capable of putting their genetic material into and out of DNA. HIV, Rous sarcoma virus, and a few others are mentioned quite often as case studies. Sometimes the viral DNA will integrate right next to, or within, a cellular gene, such as one that controls the speed at which a cell reproduces. And sometimes when that viral DNA is excised out from the cellular DNA, it takes along extra "cargo" unintentionally, and this cargo can be "junk DNA" or perfectly viable cellular genes, and this cargo gets bound together with the viral DNA into the rest of the virus. Some viruses, like RSV (Rous sarcoma virus), that cause cancer do it precisely because of this extra "foreign" genetic material that they take a long. In the case of RSV, it's a form of a mutated Ras gene, which probably came from a cell an ancestral RSV variant infected in the past. Putting a mutated form (when the viral DNA invades) of Ras into a cell which has a perfectly fine copy of Ras can cause the cell to start to reproduce quickly and uncontrollably. In some cases, it can cause cancer and the end of that cell line or organism, who gets the virus. In others, it's a way to swap genes between cells, individuals, or species, and may be rewarding. It allows genetic diversity without evolving a whole new gene.

[maikeru]

In the past decade, researchers have discovered that Tibetan villagers living in altitudes of over 4,000 M are genetically adapted to do so.

 

At least one extra gene helps their blood cells bind more oxygen, and also appears to boost their reproductive fitness under low-oxygen conditions.

 

Within the past 10,000 years or so, these Tibetans have evolved genetically to be adapted to their environment.

 

SOURCE"Big Ideas in Science" ed H. Swain JC Lon. 2002

Questions:-

1)Isn't this too quick for Natural Selection?

 

No, not necessarily. Humans have a lot of "silent" genes which are either deactivated by mutations or because of epigenetic/DNA-silencing factors (like DNA methylation, a way that cells regulate which genes are on and which ones are off, or transposons, "jumping genes" which can embed themselves right in the middle of a gene and destroy its functionality). But as others already mention, the mere acts of sex and cellular division & repair create diversity in the form of mutations. Some of these mutations can turn off genes, some can turn silent ones back on. It depends where and what happens in the mutation and which gene it happens in. One of the genes I mentioned in my previous post, Ras, actually has a couple different variants, and it's likely that there are more duplicated, but defunct versions of this gene in our genomes. Depending on how degraded that gene is, it's more than possible that a single-point mutation which may have deactivated a gene could be switched back on by another mutation that reverses the effects.

 

Also, another adaptation to low O2 and high altitudes occurred among certain South American Indians living in Peru high up in the Andes. They have barrel-shaped chests and a better ability to extract O2 than lowlanders.

 

2) Do they really mean "extra gene"?

If so, where did it come from?

 

See above. I would need to read the actual paper and know which gene they were talking about. But it's not inconceivable. There may be hundreds or thousands of different genes or versions of genes that lie silently in the genome. There are some gene "superfamilies," such as the Immunoglobulin, or Ig, superfamily (one which plays a role in so many proteins of the immune system), in which hundreds of genes are all related to some primordial gene, and if extended, could include dversions or different genes that are related, but silent or nonfunctional, because of mutational or expressional problems (such as a gene could still be transcribed, but one of the regulatory processes used in gene transcription or translation, which leads to a gene ultimately being expressed, might destroy its expression--and thus no gene expression/protein).

 

3)Could the extreme climatic conditions forced the expression of genetic material already available to all of us?

 

Maybe. Sorry, have to run at the moment. Hope these replies help.

[erKa]

No, not necessarily. Humans have a lot of "silent" genes which are either deactivated by mutations or because of epigenetic/DNA-silencing factors (like DNA methylation, a way that cells regulate which genes are on and which ones are off, or transposons, "jumping genes" which can embed themselves right in the middle of a gene and destroy its functionality). But as others already mention, the mere acts of sex and cellular division & repair create diversity in the form of mutations. Some of these mutations can turn off genes, some can turn silent ones back on. It depends where and what happens in the mutation and which gene it happens in. One of the genes I mentioned in my previous post, Ras, actually has a couple different variants, and it's likely that there are more duplicated, but defunct versions of this gene in our genomes. Depending on how degraded that gene is, it's more than possible that a single-point mutation which may have deactivated a gene could be switched back on by another mutation that reverses the effects.

 

Also, another adaptation to low O2 and high altitudes occurred among certain South American Indians living in Peru high up in the Andes. They have barrel-shaped chests and a better ability to extract O2 than lowlanders.

 

 

 

See above. I would need to read the actual paper and know which gene they were talking about. But it's not inconceivable. There may be hundreds or thousands of different genes or versions of genes that lie silently in the genome. There are some gene "superfamilies," such as the Immunoglobulin, or Ig, superfamily (one which plays a role in so many proteins of the immune system), in which hundreds of genes are all related to some primordial gene, and if extended, could include dversions or different genes that are related, but silent or nonfunctional, because of mutational or expressional problems (such as a gene could still be transcribed, but one of the regulatory processes used in gene transcription or translation, which leads to a gene ultimately being expressed, might destroy its expression--and thus no gene expression/protein).

 

 

 

Maybe. Sorry, have to run at the moment. Hope these replies help.

No. This rule accomplish as well neo-Lamarkian theory as well neo-Darwinist theory. The very inner difference between those opposite but legitimate points of view is not in the evolutive process inside taxa (..cleared! it happens really...) but in what happens during the hidden & totally unknown phoenomenon of speciation. There must be a break point before it the evolving taxon is still able to reproduce itself by sexual laws with any other fertile member of the opposite sex but same taxon: after the break point (a chiralic simmetrical bilateral fracture)there are 2 (..and not 3 or n ) new taxa not inter-fertiles between them and with the superseeded taxon, now reduced to a sudden sure extinction. There must be an unknown molecular process starting from DNA through specific proteins by mean of wich the proteins of evolved couple of newest taxa are not any more interfertiles between their correspondant and the old superseeded one. The second stage is the sudden extinction of the less adaptative taxon of the couple by natural selection following the common sense well known rules, but this is another thread. The key to understand the chemistry of speciation could be in paleontological hands: about 500-600 millions years ago (pre-Cambrian) there were funny animals having more than 2 sexual expressions (...5 different sex recognized for the same taxon!). What evil might be the extinction & speciation rules for a 5-sex taxon? There must be an unknown geometrical topological link among specific proteins of taxon, sexual expression, extinction & speciation. Darwin's extreme thought is hidden here, in the depth of the abyss of time.

[maikeru]

No. This rule accomplish as well neo-Lamarkian theory as well neo-Darwinist theory. The very inner difference between those opposite but legitimate points of view is not in the evolutive process inside taxa (..cleared! it happens really...) but in what happens during the hidden & totally unknown phoenomenon of speciation. There must be a break point before it the evolving taxon is still able to reproduce itself by sexual laws with any other fertile member of the opposite sex but same taxon: after the break point (a chiralic simmetrical bilateral fracture)there are 2 (..and not 3 or n ) new taxa not inter-fertiles between them and with the superseeded taxon, now reduced to a sudden sure extinction. There must be an unknown molecular process starting from DNA through specific proteins by mean of wich the proteins of evolved couple of newest taxa are not any more interfertiles between their correspondant and the old superseeded one. The second stage is the sudden extinction of the less adaptative taxon of the couple by natural selection following the common sense well known rules, but this is another thread. The key to understand the chemistry of speciation could be in paleontological hands: about 500-600 millions years ago (pre-Cambrian) there were funny animals having more than 2 sexual expressions (...5 different sex recognized for the same taxon!). What evil might be the extinction & speciation rules for a 5-sex taxon? There must be an unknown geometrical topological link among specific proteins of taxon, sexual expression, extinction & speciation. Darwin's extreme thought is hidden here, in the depth of the abyss of time.

 

To be quite honest, erKa, I'm having a hard time understanding your post. The possible "switching on" of a silent and defunct (pseudo)gene, which might otherwise be considered useless junk DNA, is a well-known phenomenon in plants, animals, AND people. Whether the mutation is a point-mutation or a transposon stuck in the middle of a gene that normally codes for something, sometimes they are reactivated by the process of mutation (let's say, an original mutation deactivates a gene by an A --> C substitution in the promoter, but later that C --> A again) or genetic material transfer. If reactivated, this gene could be redundant or useless or it may start to take on new functions if pressures select for it and mutations change it. But it is true that such a change would have to be first selected by natural selection, then passed on to offspring for it to have a hold in the population and later on, through further natural selection, to be involved in speciation. I'm saying it's a possibility. Evolution comes down to a lot of probabilities and possibilities and what is selected for, what is not, and what is retained.

 

However, the reactivation of one or a few genes is unlikely, I think, to create infertility or any incompatibility for the chromosomes to pair up or swap genetic material, just because the overwhelming amount of genetic material will be compatible and of similar uniformity. (Unless the gene or genes cause some type of decrease in reproductive fitness.) What we need to keep in mind is that most mutations are detrimental or not noticeable, but sometimes they can create astonishing results and thus in the individuals who carry them. Some mutations in CCR5, one of the proteins required by HIV to enter white blood cells, give virtual immunity to the disease by HIV's inability to start a productive infection. There are also genes which are controlled at the transcriptional or translational level, but produce no product (protein) and seem to have no use for the cell. Yet they still remain "on" in a certain sense, even though the cell does not have a need for them. They are likely ones which will pass into eventual oblivion, as many retroviral genes embedded in our DNA, from millions of years ago, have.

 

Genetics and gene control are complicated topics, and ones which I could use a better background in, but it becomes clear with some study, that evolution can work on more subtle and quick means than we normally think possible. Molecular biology and our current understanding of genetics allow for us to understand why things like "punctuated equilibrium," such as Gould advocated, are possible in evolution. Evolution need not be gradual, it can be rapid, but only as rapid as the mechanisms can engineer it and pressures select for it.

[Michaelangelica]

 

Also, another adaptation to low O2 and high altitudes occurred among certain South American Indians living in Peru high up in the Andes. They have barrel-shaped chests and a better ability to extract O2 than lowlanders.

Wow!

So many heavy posts

So little time

Just a comment on the above.

Chewing cocaine leaves helps O2 'whatever' assimilation? at high altitudes. So did the plant evolve to help the Indians do you think? It has certainly ensured its (the plant's) survival ?:eek: :phones:

I will have a BIG THINK about other posts and come back

 

PS

Could you please paragraph or even break after sentences with posts? Otherwise it is like being hit over the head with a typewriter.

PSS

How come i get this:-

"You must spread some Reputation around before giving it to maikeru again.";

when you are not showing any rep power?