Register | Sign In


Understanding through Discussion


EvC Forum active members: 65 (9162 total)
2 online now:
Newest Member: popoi
Post Volume: Total: 915,815 Year: 3,072/9,624 Month: 917/1,588 Week: 100/223 Day: 11/17 Hour: 0/0


Thread  Details

Email This Thread
Newer Topic | Older Topic
  
Author Topic:   "Macro" vs "Micro" genetic "kind" mechanism?
Rrhain
Member
Posts: 6351
From: San Diego, CA, USA
Joined: 05-03-2003


Message 31 of 248 (122250)
07-05-2004 9:03 PM
Reply to: Message 27 by RAZD
07-05-2004 8:36 PM


Re: another thought for the LUCA people
RAZD writes:
quote:
can one develop a chromosome family tree?
To some degree, at least, yes.
If you look at the human chromosome 2, it looks exactly like a fused chromosome 2p and 2q of chimps, gorillas, and orangutans.
Chromosomes have telomeres on the end...long strings of code on the end that essentially let the enzymes know that the end of the chromosome is coming up. If you look at the human chromosome 2, there is a telomeric sequence right in the middle of one of the branches. If you look at the tagging sequence, the rest of the chromosome below the telomeric sequence is a reversed version of the other primates chromosomes:
Human:
centromere-abcdefg-telomeric-zyxwvut-telomere
Chimp:
centromere-abcdefg-telomere
centromere-tuvwxyz-telomere
And while we're on it, there's the evidence of the centromere scar on the human chromosome 2. The full description:
Human:
telomere-123456-centromere-abcdefg-telomeric-zyxwvut-centromeric-0987-telomere
Chimp:
telomere-123456-centromere-abcdefg-telomere
telomere-7890-centromere-tuvwxyz-telomere
It is quite clear that the human chromosome 2 is a fusion of ancestral chromosomes 2p and 2q:
Human Chromosome 2 is a fusion of two ancestral chromosomes

Rrhain
WWJD? JWRTFM!

This message is a reply to:
 Message 27 by RAZD, posted 07-05-2004 8:36 PM RAZD has replied

Replies to this message:
 Message 37 by RAZD, posted 07-05-2004 9:25 PM Rrhain has replied

  
pink sasquatch
Member (Idle past 6022 days)
Posts: 1567
Joined: 06-10-2004


Message 32 of 248 (122252)
07-05-2004 9:10 PM
Reply to: Message 27 by RAZD
07-05-2004 8:36 PM


chromosome analysis
RAZD writes:
can one develop a chromosome family tree?
Yes. In fact, there is a group working on characterizing the "ancestral placental mammalian karyotype" - putatively the genome (at chromosomal segment level) of the mammalian species from which evolved all other mammals.
A review on the project (a few years old):
Evolution of mammalian genome organization inferred from comparative gene mapping.
Genome Biol. 2001;2(6):REVIEWS0005. Epub 2001 Jun 05.
Murphy WJ, Stanyon R, O'Brien SJ.
Laboratory of Genomic Diversity, National Cancer Institute, Frederick, MD 21702-1201, USA.
Comparative genome analyses, including chromosome painting in over 40 diverse mammalian species, ordered gene maps from several representatives of different mammalian and vertebrate orders, and large-scale sequencing of the human and mouse genomes are beginning to provide insight into the rates and patterns of chromosomal evolution on a whole-genome scale, as well as into the forces that have sculpted the genomes of extant mammalian species.
free pdf: NCBI
Original research from the same group (more recent):
The origin of human chromosome 1 and its homologs in placental mammals.
Genome Res. 2003 Aug;13(8):1880-8. Epub 2003 Jul 17.
Murphy WJ, Fronicke L, O'Brien SJ, Stanyon R.
Laboratory of Genomic Diversity, National Cancer Institute, Frederick, Maryland 21702, USA.
Developing ordered gene maps from multiple mammalian species coupled with chromosome-painting data provide a powerful resource for resolving the evolutionary history of chromosomes and whole genomes. In this work, we recapitulate the evolutionary history of human chromosome 1 and its homologs in placental mammals, putatively the largest physical unit in the ancestral placental genome. Precise definition of translocation exchange breakpoints in human, carnivore, cetartiodactyl, and rodent-ordered gene maps demonstrate that chromosome breakpoints, previously considered as equivalent, actually represent distinct chromosome positions and exchange events...
RAZD writes:
can {seperation \ duplication-modification \ addition \ deletion} of chromosomes be used to track "macro" levels of evolution the way mutations within gene sequences is used?
No, at a simple level, since separation/duplication/modification/addition/deletion of chromosomes is really separation/duplication/modification/addition/deletion of genes - the gene or regulation level changes effect evolution, whether micro- or macro-. Chromosome level changes do not, except when those changes result in alterations at the gene level.
My personal bias is that structure of gene families and complexity of regulation will define macroevolution more than chromosome-level changes.

This message is a reply to:
 Message 27 by RAZD, posted 07-05-2004 8:36 PM RAZD has replied

Replies to this message:
 Message 38 by RAZD, posted 07-05-2004 9:29 PM pink sasquatch has replied

  
NosyNed
Member
Posts: 8996
From: Canada
Joined: 04-04-2003


Message 33 of 248 (122256)
07-05-2004 9:16 PM
Reply to: Message 18 by pink sasquatch
07-05-2004 7:16 PM


They are there!
A good question; my first thought: a possible mechanism would utilize a "kind"-specific subset of absolutely mutation-proof genes, perhaps involved in reproduction. These genes would represent the signature for each "kind" and thus define each kind.
I'm going to be very lazy and not look anything up. This is off the top of my head.
The mutation-proof genes you want are there! As I recall there are certain processes involved with cell division that are very, very common (not exactly mutation proof but nearly). They are so crucial that if they mutate the result is selected out.
So these define "kind" as you have suggested.
However, it seems that all forms of life carry them.
This message has been edited by NosyNed, 07-05-2004 08:16 PM

This message is a reply to:
 Message 18 by pink sasquatch, posted 07-05-2004 7:16 PM pink sasquatch has replied

Replies to this message:
 Message 36 by RAZD, posted 07-05-2004 9:22 PM NosyNed has not replied
 Message 40 by pink sasquatch, posted 07-05-2004 9:33 PM NosyNed has not replied

  
RAZD
Member (Idle past 1405 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 34 of 248 (122257)
07-05-2004 9:18 PM
Reply to: Message 30 by jar
07-05-2004 8:59 PM


Re: Just a favor if you please...
or do lumberjacks make up the chorus?
{"I'm a lumberjack and I'm okay ..."}
what about computer generated? create a program to evolve new arguments ...
ahahahahahahaaaaa

we are limited in our ability to understand
by our ability to understand
RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}

This message is a reply to:
 Message 30 by jar, posted 07-05-2004 8:59 PM jar has not replied

  
pink sasquatch
Member (Idle past 6022 days)
Posts: 1567
Joined: 06-10-2004


Message 35 of 248 (122258)
07-05-2004 9:19 PM
Reply to: Message 30 by jar
07-05-2004 8:59 PM


Just til I can retire...
One Million Dollars a Month. One Million Dollars a Month.
I'm in, perhaps as a "reasonable professorial type" - we might need a few of those to lend legitimacy.
Perhaps after a year or two, when we've filled our coffers beyond our wildest dreams, we can slowly start slipping pro-evolution/anti-creationist propaganda in to really confuse the rubes...

This message is a reply to:
 Message 30 by jar, posted 07-05-2004 8:59 PM jar has not replied

Replies to this message:
 Message 39 by RAZD, posted 07-05-2004 9:31 PM pink sasquatch has not replied

  
RAZD
Member (Idle past 1405 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 36 of 248 (122261)
07-05-2004 9:22 PM
Reply to: Message 33 by NosyNed
07-05-2004 9:16 PM


Re: They are there!
so that makes us all one kind?
don't think that helps the creationists ...

This message is a reply to:
 Message 33 by NosyNed, posted 07-05-2004 9:16 PM NosyNed has not replied

  
RAZD
Member (Idle past 1405 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 37 of 248 (122262)
07-05-2004 9:25 PM
Reply to: Message 31 by Rrhain
07-05-2004 9:03 PM


Re: another thought for the LUCA people
sweet. I knew there was a different number 42 (2x21) human and 46? (2x23) chimp?
also different number between horse and donkey is given as reason for the sterility of the mule.

This message is a reply to:
 Message 31 by Rrhain, posted 07-05-2004 9:03 PM Rrhain has replied

Replies to this message:
 Message 41 by Rrhain, posted 07-05-2004 9:45 PM RAZD has replied

  
RAZD
Member (Idle past 1405 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 38 of 248 (122263)
07-05-2004 9:29 PM
Reply to: Message 32 by pink sasquatch
07-05-2004 9:10 PM


Re: chromosome analysis
thanks. do you know what current theories there are for changing numbers of chromosomes? one obvious one is polyploidy, but it seems a little bit like a sledge hammer when a jewelers tap is more appropriate.

we are limited in our ability to understand
by our ability to understand
RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}

This message is a reply to:
 Message 32 by pink sasquatch, posted 07-05-2004 9:10 PM pink sasquatch has replied

Replies to this message:
 Message 42 by pink sasquatch, posted 07-05-2004 9:50 PM RAZD has replied
 Message 43 by coffee_addict, posted 07-06-2004 12:00 AM RAZD has replied
 Message 44 by coffee_addict, posted 07-06-2004 12:00 AM RAZD has seen this message but not replied

  
RAZD
Member (Idle past 1405 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 39 of 248 (122265)
07-05-2004 9:31 PM
Reply to: Message 35 by pink sasquatch
07-05-2004 9:19 PM


Re: Just til I can retire...
Or use the profits to fund research? (oh the irony eh?)
Of course you could also become your own critic just to keep the flames going?

we are limited in our ability to understand
by our ability to understand
RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}

This message is a reply to:
 Message 35 by pink sasquatch, posted 07-05-2004 9:19 PM pink sasquatch has not replied

  
pink sasquatch
Member (Idle past 6022 days)
Posts: 1567
Joined: 06-10-2004


Message 40 of 248 (122266)
07-05-2004 9:33 PM
Reply to: Message 33 by NosyNed
07-05-2004 9:16 PM


One "kind", everybody wins!
Hey Nosy,
So these define "kind" as you have suggested.
However, it seems that all forms of life carry them.
What an idea you've tripped upon! If there is only a single "kind" that includes all life, then there is no need for this silly micro- and macro-evolution stuff, since evolution only occurs within "kind."
But seriously, I think you're talking about certain basic gene domains that are translated into the individual activities of a protein - in many cases these are highly conserved (though I'm not sure if any are completely conserved, especially since neutral mutations would be allowed).
These domains are important because they've allowed the evolution of countless genes with the same basic activity, but different overall activity due to differences in surrounding sequence or addition of other types of domains. Thus every single gene did not have to arise by chance, though the ancestral domain may have.
In any case, these domains are short stretches of sequence - even highly conserved genes like those coding for the ribosomes are quite divergent in sequence, even if their activity domains are identical.
I'd been interested to find out which gene holds the title for the most conserved sequence during evolution.

This message is a reply to:
 Message 33 by NosyNed, posted 07-05-2004 9:16 PM NosyNed has not replied

Replies to this message:
 Message 46 by Brad McFall, posted 07-06-2004 12:14 AM pink sasquatch has not replied
 Message 49 by RAZD, posted 07-06-2004 12:24 AM pink sasquatch has replied

  
Rrhain
Member
Posts: 6351
From: San Diego, CA, USA
Joined: 05-03-2003


Message 41 of 248 (122268)
07-05-2004 9:45 PM
Reply to: Message 37 by RAZD
07-05-2004 9:25 PM


Re: another thought for the LUCA people
RAZD responds to me:
quote:
sweet. I knew there was a different number 42 (2x21) human and 46? (2x23) chimp?
Just because I'm being pedantic:
You do know those numbers can't be right. If I fuse two chromosomes into one, I have only lost one chromosome, not two. Thus, if humans are n (diploid), then chimps must be n+2 (diploid) and not n+4.
OK...enough being pissy.
Humans have 46, our close primate relatives have 48.
quote:
also different number between horse and donkey is given as reason for the sterility of the mule.
Yes, but that in and of itself is not sufficient. Przewalski's horse has 66 chromosomes compared to the common horse's 64. And yet, they can breed and produce fertile offspring...with 65 chromosomes.
So yes, differing chromosomal count is a problem for producing fertile offspring, but it is not a "never" criterion.

Rrhain
WWJD? JWRTFM!

This message is a reply to:
 Message 37 by RAZD, posted 07-05-2004 9:25 PM RAZD has replied

Replies to this message:
 Message 50 by RAZD, posted 07-06-2004 12:26 AM Rrhain has replied

  
pink sasquatch
Member (Idle past 6022 days)
Posts: 1567
Joined: 06-10-2004


Message 42 of 248 (122269)
07-05-2004 9:50 PM
Reply to: Message 38 by RAZD
07-05-2004 9:29 PM


Re: chromosome analysis
do you know what current theories there are for changing numbers of chromosomes?
Depending on how a chromosome splits, or two chromosome fuse, there isn't necessarily a major detriment to the function of any of the genes on those chromosomes. The real problem is during cell division - depending on where the centromeres end up, huge chunks of genetic info can be lost or gained during division. In some rare cases in mice fusions have spontaneously arisen that don't wreak havoc on chromosome sorting and reproduction - if you are interested you might do a search on "Robertsonian translocations," since I'm feeling a bit rusty on the subject. (A similar example in humans is the Philadelphia translocation, though it hybridizes two genes, resulting in childhood leukemia...)
I would think that if you had a small subpopulation arise with a chromosome fusion or division that was reproductively incompatible with the parental karyotype, you could potentially end up with reproductive isolation and speciation.
As far as how splits/fusions/rearrangments occur, I'm fuzzy on the details, though I know they are a very active area of study. I know there are "recombination hot-spots" on some chromosomes that facilitate recombination errors (they are often large areas of repetitive sequence that confuse the DNA handling proteins). Chromosome breakage can occur with certain environmental insults (caffeine, for one, which is bad for coffee addicts like myself...), though they may have to occur after a fusion event so that following the break both pieces have a centromere to avoid loss during division.

This message is a reply to:
 Message 38 by RAZD, posted 07-05-2004 9:29 PM RAZD has replied

Replies to this message:
 Message 48 by RAZD, posted 07-06-2004 12:22 AM pink sasquatch has not replied

  
coffee_addict
Member (Idle past 477 days)
Posts: 3645
From: Indianapolis, IN
Joined: 03-29-2004


Message 43 of 248 (122284)
07-06-2004 12:00 AM
Reply to: Message 38 by RAZD
07-05-2004 9:29 PM


Re: chromosome analysis
RAZD writes:
do you know what current theories there are for changing numbers of chromosomes?
Here is one obvious one, but not so obvious for most people. The Y-chromosome is getting smaller my the generation. Many biologists think that it's going to disappear or join the X-chromosome in the distant future. Wouldn't that be sad? No more guys. Only ladies.

The Laminator

This message is a reply to:
 Message 38 by RAZD, posted 07-05-2004 9:29 PM RAZD has replied

Replies to this message:
 Message 47 by pink sasquatch, posted 07-06-2004 12:20 AM coffee_addict has replied
 Message 51 by RAZD, posted 07-06-2004 12:29 AM coffee_addict has not replied

  
coffee_addict
Member (Idle past 477 days)
Posts: 3645
From: Indianapolis, IN
Joined: 03-29-2004


Message 44 of 248 (122285)
07-06-2004 12:00 AM
Reply to: Message 38 by RAZD
07-05-2004 9:29 PM


Re: chromosome analysis
Edited by Lam - Double post.
This message has been edited by Lam, 07-05-2004 11:01 PM

The Laminator

This message is a reply to:
 Message 38 by RAZD, posted 07-05-2004 9:29 PM RAZD has seen this message but not replied

  
coffee_addict
Member (Idle past 477 days)
Posts: 3645
From: Indianapolis, IN
Joined: 03-29-2004


Message 45 of 248 (122289)
07-06-2004 12:06 AM
Reply to: Message 28 by jar
07-05-2004 8:39 PM


Re: Just a favor if you please...
jar writes:
I've often wondered if we should not get together and start our own Creationist site.
If you ever become serious about this, count me in. I have heard enough creationist arguments, both in real life and online, that I believe I can come off as more a creationist than any genuine creationist can be. I've heard more creationist straw man than some creationists I know. Actually, sometimes I can make a better creationist argument than some creationists I know just because I know the technical stuff more than them.
I bet we can be far better than the real creationists out there because of our technical backgrounds.

The Laminator

This message is a reply to:
 Message 28 by jar, posted 07-05-2004 8:39 PM jar has not replied

  
Newer Topic | Older Topic
Jump to:


Copyright 2001-2023 by EvC Forum, All Rights Reserved

™ Version 4.2
Innovative software from Qwixotic © 2024