Author Topic: genetic variation  (Read 11243 times)

Offline mako

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genetic variation
« on: September 20, 2011, 07:14:12 PM »
I had to spin this off of one of the other threads.  The world population argument makes no sense if we stop and look for just a minute.  One of the key issues when you go out to select a dog (or any animal for that matter) from a breeder is you want to know it's pedigree.  This is to ensure that the animal you select wasn't the product of inbreeding.  The underlying principle is genetic variation.  The greater the variation, the fewer opportunities for recessive traits to be inherited.  If our planet started with only 8 human subjects, there isn't sufficient initial genetic variation to support the current population of 6 billion or so.

Offline ctc

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Re: genetic variation
« Reply #1 on: September 20, 2011, 09:04:47 PM »
You are kidding, right?  Have you no clue how genetic information is contained in DNA?

BTW - the pedigree with dogs shows "inbreeding".  That is how man develops different traits in dogs.
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Offline mako

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Re: genetic variation
« Reply #2 on: September 20, 2011, 09:38:35 PM »
I know precisely how DNA works.  There is not enough DNA contained in 8 specimens of the species Homo Sapiens to account for the current genetic variation.   The Human Genome Project identified between 20,000 and 25,000 human genes.  We could not have the modern human genetic variation if we started with only 8 specimens.  Ask any reputable biologist or geneticist.  Your pastor does not count.  You really should avoid commenting on topics regarding science.  Your ignorance is so profound I am not sure where to begin.

Offline drmuscle

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Re: genetic variation
« Reply #3 on: September 20, 2011, 10:10:28 PM »
Dog are inbred almost exclusively. In the breeding world it's refereed to as line breeding.
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Offline Ray Brinzer

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Re: genetic variation
« Reply #4 on: September 20, 2011, 10:26:16 PM »
I know precisely how DNA works.

Wow.

Offline mako

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Re: genetic variation
« Reply #5 on: September 20, 2011, 11:09:33 PM »
Yeah I am guilty of exaggeration, but I do know enough to understand genetic variation and that 8 members of a species are insufficient to maintain the current variation.

Offline ctc

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Re: genetic variation
« Reply #6 on: September 21, 2011, 08:32:45 AM »
Yeah I am guilty of exaggeration, but I do know enough to understand genetic variation and that 8 members of a species are insufficient to maintain the current variation.
Apparently, you are not smart enough to know that according to Richard Dawkins, there is enough information in the DNA of the simpliest life form known to man to fill 1000 volumes of Encyclopedia Britannica to .  That would be a stack about 70 yards tall.  Your "20,000 identified" is simply ignorant.  Obviously, you are clueless.  Thank you, though, for your continued personal attacks.  It makes you look "superior".   ::)
"We can state with conviction, therefore, that a man's support for absolute government is in direct proportion to the contempt he feels for his country" - Alexis de Tocqueville

Offline coachsparky

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Re: genetic variation
« Reply #7 on: September 21, 2011, 10:02:45 AM »
Yeah I am guilty of exaggeration, but I do know enough to understand genetic variation and that 8 members of a species are insufficient to maintain the current variation.
Apparently, you are not smart enough to know that according to Richard Dawkins, there is enough information in the DNA of the simpliest life form known to man to fill 1000 volumes of Encyclopedia Britannica to .  That would be a stack about 70 yards tall.  Your "20,000 identified" is simply ignorant.  Obviously, you are clueless.  Thank you, though, for your continued personal attacks.  It makes you look "superior".   ::)

The clueless one is the crazy texas coach once again.  mako is correct the number of identified in humans is in the 20000 to 25000 range.  Open mouth insert foot dumb dumb.

http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/H/HGP.html

Quote
1. The number of genes turned out to be much smaller than once predicted.
The two groups came up with slightly different estimates of the number of protein-encoding genes, but both in the range of 30 to 38 thousand:
•barely two times larger than the genomes of
◦Drosophila (~17,000 genes)
◦C. elegans (<22,000 genes)
•and representing only 1– 2% of the total DNA in the cell;
•and a third of the 100,000 genes that many had predicted would be found.
•(By 2011, the number had been reduced to some 21,000.)
Are the tiny roundworm and fruit fly almost as complex as we are?

Probably not, although we share many homologous genes (called "orthologs") with both these animals.
But,

•many of our protein-encoding genes produce more than one protein product (e.g., by alternative splicing of the primary transcript of the gene). On average, each of our ORFs produces 2 to 3 different proteins.
So the human "proteome" (our total number of proteins) may be 10 or more times larger than that of the fruit fly and roundworm.

•A larger proportion of our genome
◦encodes transcription factors
◦is dedicated to control elements (e.g., enhancers) to which these transcription factors bind.
The combinatorial use of these elements probably provides much greater flexibility of gene expression than is found in Drosophila and C. elegans.
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Offline drmuscle

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Re: genetic variation
« Reply #8 on: September 21, 2011, 10:13:56 AM »
But the first single cell organism had enough DNA to give way to every creature on earth?
From professing themselves to be wise they became fools.

Offline coachsparky

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Re: genetic variation
« Reply #9 on: September 21, 2011, 10:23:53 AM »
But the first single cell organism had enough DNA to give way to every creature on earth?

Actually scientist now believe the first single celled organisms had no DNA whatsoever.  The precurser to DNA is a simpler form called RNA, but they believe they did not have that either, they had another mechanism, much less developed and RNA and DNA evolved from this precursor.
We can easily forgive a child who is afraid of the dark;  the real tragedy of life is when men are afraid of the light.

Bigotry disguised as religious liberty is still BIGOTRY

Offline ctc

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Re: genetic variation
« Reply #10 on: September 21, 2011, 10:25:12 AM »
But the first single cell organism had enough DNA to give way to every creature on earth?
Quit making Mako look foolish.  He is doing fine on his own.   ;D
"We can state with conviction, therefore, that a man's support for absolute government is in direct proportion to the contempt he feels for his country" - Alexis de Tocqueville

Offline coachsparky

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Re: genetic variation
« Reply #11 on: September 21, 2011, 10:26:28 AM »
But the first single cell organism had enough DNA to give way to every creature on earth?
Quit making Mako look foolish.  He is doing fine on his own.   ;D

the crazy texas coach just cannot help it, he likes being the forum jester.  Open mouth, insert foot again.
We can easily forgive a child who is afraid of the dark;  the real tragedy of life is when men are afraid of the light.

Bigotry disguised as religious liberty is still BIGOTRY

Offline drmuscle

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Re: genetic variation
« Reply #12 on: September 21, 2011, 10:40:33 AM »
At some point there had to be a single first one.
From professing themselves to be wise they became fools.

Offline coachsparky

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Re: genetic variation
« Reply #13 on: September 21, 2011, 10:45:42 AM »
At some point there had to be a single first one.

Yes but it did not have to have DNA.  DNA could have taken many millions of years to develop from the precursor materials.

From the September 2009 issue of Scientific American:

Quote
Life on Earth
BY Alonso Ricar do and Jack W. Szostak
Fresh clues hint at how the
first living organisms arose
from inanimate matter

On the other hand, the paradox would disappear if the first organisms did not require proteins at all. Recent experiments suggest it would have been possible for genetic molecules similar to DNA or to its close relative RNA to form spontaneously. And because these molecules can curl up in different shapes and act as rudimentary catalysts, they may have become able to copy themselves—to reproduce—without the need for proteins. The earliest forms of life could have been simple membranes made of fatty acids—also structures known to form spontaneously—that enveloped water and these self-replicating genetic molecules. The genetic material would encode the traits that each generation handed down to the next, just as DNA does in all things that are alive today. Fortuitous mutations, appearing at random in the copying process, would then propel evolution, enabling these early cells to adapt to their environment, to compete with one another, and eventually to turn into the lifeforms we know.
« Last Edit: September 21, 2011, 11:01:48 AM by coachsparky »
We can easily forgive a child who is afraid of the dark;  the real tragedy of life is when men are afraid of the light.

Bigotry disguised as religious liberty is still BIGOTRY

Offline Cougar1

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Re: genetic variation
« Reply #14 on: September 21, 2011, 11:04:28 AM »
But the first single cell organism had enough DNA to give way to every creature on earth?

+1 for drmuscle
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