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Author Topic:   Simultaneous Evolution?
barbara
Member (Idle past 2156 days)
Posts: 167
Joined: 07-19-2010


Message 31 of 42 (581887)
09-17-2010 11:22 PM
Reply to: Message 30 by crashfrog
09-17-2010 10:41 PM


Re: RNA World?
Does a RNA virus have enough genes to form a chromosome? Not that they do but is it enough?

Edited by barbara, : No reason given.


This message is a reply to:
 Message 30 by crashfrog, posted 09-17-2010 10:41 PM crashfrog has responded

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 Message 32 by crashfrog, posted 09-17-2010 11:23 PM barbara has responded

    
crashfrog
Inactive Member


Message 32 of 42 (581890)
09-17-2010 11:23 PM
Reply to: Message 31 by barbara
09-17-2010 11:22 PM


Re: RNA World?
Does a RNA virus have enough genes to form a chromosome?

They have a single chromosome comprised of single-stranded RNA.


This message is a reply to:
 Message 31 by barbara, posted 09-17-2010 11:22 PM barbara has responded

Replies to this message:
 Message 33 by barbara, posted 09-17-2010 11:59 PM crashfrog has responded

  
barbara
Member (Idle past 2156 days)
Posts: 167
Joined: 07-19-2010


Message 33 of 42 (581896)
09-17-2010 11:59 PM
Reply to: Message 32 by crashfrog
09-17-2010 11:23 PM


Re: RNA World?
Since a RNA virus is a single chromosome then isn't logical to think that since we have 23 chromosomes X2 each parent that our chromosomes are actually RNA viruses linked together with all of their information put into DNA storage?

What does a single human chromosome contain in information?

Can science identify each chromosome for what it does?

Edited by barbara, : No reason given.

Edited by barbara, : No reason given.


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 Message 35 by crashfrog, posted 09-18-2010 2:29 PM barbara has not yet responded
 Message 36 by RAZD, posted 09-18-2010 2:58 PM barbara has not yet responded
 Message 39 by Dr Jack, posted 09-23-2010 6:11 AM barbara has responded

    
frako
Member
Posts: 2678
From: slovenija
Joined: 09-04-2010
Member Rating: 2.0


Message 34 of 42 (581926)
09-18-2010 7:18 AM
Reply to: Message 33 by barbara
09-17-2010 11:59 PM


Re: RNA World?
Since a RNA virus is a single chromosome then isn't logical to think that since we have 23 chromosomes X2 each parent that our chromosomes are actually RNA viruses linked together with all of their information put into DNA storage?

there are some hypothesis that suggest that the first cell had no dna and that dna was introduced later

What does a single human chromosome contain in information?

a whole lot in "bits and bites" i have no idea though some worms have more gens than humans do.

Can science identify each chromosome for what it does?

well the Y chromosome is responsible for a human ofspring to be a man, though im guessing your asking about gens they dont know every gen but they do know what some gens do they are still working on the others i think iceland has a project that is trying to determine what individual gens do.


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crashfrog
Inactive Member


Message 35 of 42 (581987)
09-18-2010 2:29 PM
Reply to: Message 33 by barbara
09-17-2010 11:59 PM


Re: RNA World?
Since a RNA virus is a single chromosome then isn't logical to think that since we have 23 chromosomes X2 each parent that our chromosomes are actually RNA viruses linked together with all of their information put into DNA storage?

Why would that be reasonable? Animal-infectious RNA viruses have circular chromosomes; eukaryotic chromosomes are linear.

And if our chromosomes are viral why aren't we viruses? No, there's nothing logical about your notion.

Can science identify each chromosome for what it does?

Yes, that was the Human Genome Project which you may have heard of. You can browse it at the UCSC Genome Browser.


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RAZD
Member
Posts: 18242
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.0


Message 36 of 42 (581994)
09-18-2010 2:58 PM
Reply to: Message 33 by barbara
09-17-2010 11:59 PM


Re: RNA World?
Hi barbara, let me add something the others have not said yet.

Since a RNA virus is a single chromosome then isn't logical to think that since we have 23 chromosomes X2 each parent that our chromosomes are actually RNA viruses linked together with all of their information put into DNA storage?

RNA has a couple of fundamental differences from DNA:

  1. DNA is composed of the four bases, A, C, G and T, while RNA is composed of the four bases A, C, G and U

    http://en.wikipedia.org/wiki/DNA

    quote:
    The four bases found in DNA are adenine (abbreviated A), cytosine (C), guanine (G) and thymine (T). These four bases are attached to the sugar/phosphate to form the complete nucleotide, as shown for adenosine monophosphate.

    http://en.wikipedia.org/wiki/RNA

    quote:
    RNA is very similar to DNA, but differs in a few important structural details: in the cell, RNA is usually single-stranded, while DNA is usually double-stranded; RNA nucleotides contain ribose while DNA contains deoxyribose (a type of ribose that lacks one oxygen atom); and RNA has the base uracil rather than thymine that is present in DNA.

  2. it is normally a single strand, where DNA is normally a cross-linked double strand, where the cross-links are only between specific molecules, A only cross-links with T, and C only cross-links with G.

    This places greater structural & organizational restrictions on DNA than on RNA.

Thus a couple of changes have to happen to RNA to turn it into DNA.

Enjoy.


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shadow71
Member (Idle past 287 days)
Posts: 706
From: Joliet, il, USA
Joined: 08-31-2010


Message 37 of 42 (582670)
09-22-2010 5:30 PM


I am not a scientist, (retired trial lawyer) but since retirement have been reading extensively in re evolution and origin of life. My thoughts after reading this thread are: You are not going back far enough. What is origin of chemicals? Of universe? Am I being naive?
Replies to this message:
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AZPaul3
Member
Posts: 3422
From: Phoenix
Joined: 11-06-2006
Member Rating: 4.8


Message 38 of 42 (582671)
09-22-2010 6:03 PM
Reply to: Message 37 by shadow71
09-22-2010 5:30 PM


Not naive. Just off-topic.

Plenty of other threads cover these subjects in detail.

Welcome to EvC!

Since you're retired, kick your shoes off, grab a beer and give us the benefit of your years of service.

By way of welcome:

What’s the difference between a lawyer and a trampoline?

You take off your shoes before you jump on a trampoline.

Welcome, again!


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Dr Jack
Member
Posts: 3500
From: Leicester, England
Joined: 07-14-2003


Message 39 of 42 (582720)
09-23-2010 6:11 AM
Reply to: Message 33 by barbara
09-17-2010 11:59 PM


Our genome is not a collection of viral genomes
Since a RNA virus is a single chromosome then isn't logical to think that since we have 23 chromosomes X2 each parent that our chromosomes are actually RNA viruses linked together with all of their information put into DNA storage?

No not at all.

Our chromosomes are nothing like a viral "chromosome" (and, frankly, I think it's an abuse of the term to describe a virus as having one). As others have pointed it's DNA, but there's much than that. Each of our chromosomes is vastly larger than an entire viral genome. Our genes organised in a quite different manner (viruses often have overlapping genes, both on the same and opposite strands - this almost never happens in our genome - and our genes are organised into introns and exons, viral genes aren't) and code for very different proteins.

Bodge 23 viral genomes together and you'd just get a confused viral genome, you wouldn't get a functioning organism with genes for key functions such as membrane synthesis, cytoskeletal organisation and DNA replication and translation.

But that's pretty much an aside to the central reason it makes no sense: it doesn't match in the slightest to our evolutionary history. We may have 23 chromosomes, but we surely didn't evolve from creatures that did. In fact, looking at our Eukaryotic "cousins" it becomes apparent we almost certainly evolved from organisms with a single chromosome, composed of DNA and arranged in a similar way to our own with many, many similar genes. Stretching out of our domain and into the Archaea and Bacteria, and we again find a single DNA chromosome.

There is, actually, some reason to think that DNA was acquired by cellular life from viruses, but it certainly didn't happen in the way you suggest.

Can science identify each chromosome for what it does?

Chromosomes are not functionally specific.


This message is a reply to:
 Message 33 by barbara, posted 09-17-2010 11:59 PM barbara has responded

Replies to this message:
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barbara
Member (Idle past 2156 days)
Posts: 167
Joined: 07-19-2010


Message 40 of 42 (582730)
09-23-2010 8:59 AM
Reply to: Message 39 by Dr Jack
09-23-2010 6:11 AM


Re: Our genome is not a collection of viral genomes
I read that viruses are pure nucleic acid and they are everywhere in the biosphere. How is that different from our DNA that is made of nucleic acid?

A retrovirus that was involved in making the placenta in mammals had to have a complete sequence of genes in order to accomplish it. Correct?


This message is a reply to:
 Message 39 by Dr Jack, posted 09-23-2010 6:11 AM Dr Jack has responded

Replies to this message:
 Message 41 by Dr Jack, posted 09-23-2010 9:11 AM barbara has responded

    
Dr Jack
Member
Posts: 3500
From: Leicester, England
Joined: 07-14-2003


Message 41 of 42 (582735)
09-23-2010 9:11 AM
Reply to: Message 40 by barbara
09-23-2010 8:59 AM


Re: Our genome is not a collection of viral genomes
I read that viruses are pure nucleic acid and they are everywhere in the biosphere. How is that different from our DNA that is made of nucleic acid?

Viruses aren't made of pure nucleic acid, they also have protein elements. Viroids are pure nucleic acid, and virusoids can be. The nucleic acids involved in the virus genome can be RNA or DNA. But what they're made of is a pretty poor measure of what they are; consider that all atoms are composed of neutrons, protons and electrons - would you consider that to mean that all atoms are the same? All molecules?

The differences between the genomes are much more profound that the chemicals they are composed of.

A retrovirus that was involved in making the placenta in mammals had to have a complete sequence of genes in order to accomplish it. Correct?

Complete for a retrovirus, yes. Which means it lacks the genes required even for its own replication, as well as the genes required for any of the functions of a living cell, yet alone a living animal.

The protein(s) that allow the formation of the placenta that mammals likely acquired from a retrovirus allow the formation of synctia (cells conglomerations with one membrane and multiple nuclei). These protein(s) act by modifying existing structures and processes, they do not code for new structures.

(edit) You seem to have become particularly influenced by viral involvement in the placenta. And it is a remarkable finding but consider this: the reason it is remarkable is because its very rare. Almost everywhere we look we do not find evidence of viral involvement.

Edited by Mr Jack, : Viral involvement is rare


This message is a reply to:
 Message 40 by barbara, posted 09-23-2010 8:59 AM barbara has responded

Replies to this message:
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barbara
Member (Idle past 2156 days)
Posts: 167
Joined: 07-19-2010


Message 42 of 42 (582781)
09-23-2010 1:36 PM
Reply to: Message 41 by Dr Jack
09-23-2010 9:11 AM


Re: Our genome is not a collection of viral genomes
The protein syncytia from what I understand is the same protein in the formation of shells of egg layers. This retrovirus then should be the same sequence in all egg layers and mammals with a placenta. Correct?

Does anything make sense in genetics sequencing?

Edited by barbara, : No reason given.


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