View Full Version : Apes DNA v Human DNA.
Always Free
18th May 2003, 05:35 AM
If apes have 96% the same DNA as humans what is the other 4% that makes us what we are?
BillyJoe
18th May 2003, 06:01 AM
Alfie,
Pretty damn important don't you think?
Actually I think that 96% figure includes junk DNA (non-functional DNA). Junk DNA comprises about 95% of the total but this figure may be way out because some of the junk DNA could turn out to have a function after all. If it's a true figure, however, and the difference (4%) between human and ape DNA is in the functional DNA only, then the difference is pretty substantial.
Hell, it better be!
regards,
BillyJoe
BillyJoe
18th May 2003, 06:08 AM
This might help (http://www.wasdarwinright.com/DNArelatedness.html#Comparing%20DNA)
It is perhaps well to remember the size of the human genome of 3,200,000,000 base pairs......Although we may comprise of only 30,000 to 100,000 (high estimate) genes, each gene can comprise hundreds to thousands of base pairs, and it is the unique sequence of base pairs that makes up a gene. It can take only a few changes in the coding sequence of one gene to completely alter or inactivate the function of that gene
Always Free
18th May 2003, 06:09 AM
Originally posted by BillyJoe
Alfie,
Pretty damn important don't you think?
Actually I think that 96% figure includes junk DNA (non-functional DNA). Junk DNA comprises about 95% of the total but this figure may be way out because some of the junk DNA could turn out to have a function after all. If it's a true figure, however, and the difference (4%) between human and ape DNA is in the functional DNA only, then the difference is pretty substantial.
Hell, it better be!
regards,
BillyJoe
But why then do people, such as animal experts or scientists point out the 4% difference as if infering that there is only an actual 4% difference which I take it to mean very little difference?
I suppose I will have to look up this "junk DNA" as you describe it, myself.
BillyJoe
18th May 2003, 06:20 AM
Yeah, I think the 4% difference is across the board so that there is, in fact, a 4% difference in the functional DNA. The above link, which you probably missed before you posted, probably helps explain why such a small difference can make such a BIG difference. Goes to show too that evolution did not have much work to do to get from a chimpanzee to homo sapiens. ;)
Always Free
18th May 2003, 06:30 AM
Originally posted by BillyJoe
Yeah, I think the 4% difference is across the board so that there is, in fact, a 4% difference in the functional DNA. The above link, which you probably missed before you posted, probably helps explain why such a small difference can make such a BIG difference. Goes to show too that evolution did not have much work to do to get from a chimpanzee to homo sapiens. ;)
Chimpanzees and Humans - Still Close Relatives Despite Wayward DNA
A new study compairing chimpanzee versus human DNA showed that genetic jumbling, unnoticed before, possibly explains why humans and our closest cousins seem so different when our basic DNA structure is so much alike. The rearrangement, addition and deletion in DNA could mean that certain genes are disabled. This process may play a bigger role in evolution that previously suspected. The formerly accepted and often quoted percentage of similarity of the human and chimp genomes was 98.5%. In light of this new comparison, this estimate seems too high, but still, the genomes are far more alike than they are different.
References:
http://www.pnas.org/cgi/content/abstract/99/21/13633
Thanks for that link Bill (I did miss it) I have put that into my favs to give it a good read later on.
I'm starting to understand why 4% can be a big difference;)
arcticpenguin
18th May 2003, 07:09 AM
While the term "junk DNA" is used, it would probably be more appropriate to refer to it as "non-coding DNA". It does not code for protein sequences.
Dymanic
18th May 2003, 09:45 AM
If so little difference separates us from chimpanzees, think how much less must be the difference between one human and another. (Or, like I did, look it up. I'm finding it quoted as less than .01%).
On average, two unrelated people differ at just one of every 1,000 sites in their DNA...
But these tiny variations add up to roughly 3 million places where two people
may differ, creating traits such as hair color, eye color or shade of skin.
...Tiny variations called single nucleotide polymorphisms (SNPs), the most
common type of variation in the genome, may underlie differences in traits
such as muscle composition, the body's response to exercise and metabolic
efficiency
There is in fact less actual genetic difference between, say the shortest, blackest Pigmy and the tallest, blondest German, than we would expect (or so say some geneticists). It has been suggested (though it is still far from well-established) that the human population passed through a 'bottleneck' around 74k years ago--possibly the result of a 'volcanic winter'. I think Gould said that there is more variation in some groups of chimpanzees than there is in the entire human population worldwide.
Shane Costello
18th May 2003, 11:00 AM
People tend to get a bit carried away with the similarities between the human and primate genomes, IMO. It's important to remember that mammalian genomes are very highly preserved across species boundries. There are a lot of similarities between the human genome and those of cattle (www.biomedcentral.com/news/20001005/01) and mice (www.newscientist.com/hottopics/dna/article.jsp?id=23721000&sub=Code%20cracking). In the case of cattle (I work in the field of bovine genetics) the current estimate is that the bovine and human genome are 95% similar.
I've read that most of the differences between human and other primate genomes are in the regulatory sequences of genes, meaning that while the gene sequences are not that disimilar (if at all), they would be transcribed into mRNA at very different rates. RNA is also under post-trascriptional control, while amino acids translated from the mRNA sequence can also be under post-translational control. Nature published an article a few months ago detailing how a few base pair changes between in the same gene between humans and apes has allowed human jaw structure develop into a form capable of articulating speech.
Darwin
18th May 2003, 12:02 PM
I would just like to add that Gould mentions that it is thought that while it would seem that those genetical differences are minor,those few key genes that separate us do play a major role.
I´m using his earlier work as a reference,whether this is up to date or not I do not know of.
gmol
18th May 2003, 03:01 PM
Something that has not been mentioned in this thread is that the ape genome (as far as I know) has not been sequenced yet!
(Not that there aren't people working on it)...
We don't know the precise differences between human and ape DNA (because we don't have a whole sequence)...the percent numbers are often derived by comparing small specific places (i.e. a specific gene) on the whole genome.
Th 98% similarity between cimpanzees and humans I think is gotten from cyctochrome c comparison (i.e. 98% of the DNA bases match up with the human gene...
Genghis Pwn
18th May 2003, 03:15 PM
The number I have heard is that we share 98.6% of our "active DNA" with chimps.
I have studied Chimpanzees in Gombe. They are amazingly similar to us. The things you notice are their fingernails, their eyes, and especially their ears, which are incredibly humanlike. :D
Mercutio
18th May 2003, 03:18 PM
I don't remember who--I think it was Carl Sagan--but somebody once remarked, regarding stories of aliens mating with humans, that a human would stand a better chance mating with a geranium, since at least there there is some shared DNA, whereas the alien's DNA-equivalent would have had an entirely different evolutionary path.
So, does anyone here know what percentage of DNA we share with plants? with reptiles? amoeba?
Kate
18th May 2003, 03:29 PM
The amino acid sequences for human and chimpanzee cytochrome c are identical. You can retrieve the sequences at the NCBI site for comparison.
(http://www.ncbi.nlm.nih.gov/)
The original technique for comparing the DNA of two different organisms is to extract DNA from both, mix them together, melt them by heating the mixture (this separates the complementary strands from each other), then let them reanneal. The more similar the two genomes, the more heterogenous double helices (that is, DNA with one strand from one species and its complement from the other) form as the mixture cools. The more similar the strands, the more strongly they bond to one another. From the strength of this bonding, you can calculate the percent difference between the two sequences.
Now that we have DNA sequences for so many parts of human and chimpanzee genome (both coding and non-coding regions), we can make estimates of total differences by extrapolation from the differences in known sequences.
arcticpenguin
18th May 2003, 03:34 PM
Originally posted by Kate
The amino acid sequences for human and chimpanzee cytochrome c are identical. You can retrieve the sequences at the NCBI site for comparison.
(http://www.ncbi.nlm.nih.gov/)
The original technique for comparing the DNA of two different organisms is to extract DNA from both, mix them together, melt them by heating the mixture (this separates the complementary strands from each other), then let them reanneal. The more similar the two genomes, the more heterogenous double helices (that is, DNA with one strand from one species and its complement from the other) form as the mixture cools. The more similar the strands, the more strongly they bond to one another. From the strength of this bonding, you can calculate the percent difference between the two sequences.
Now that we have DNA sequences for so many parts of human and chimpanzee genome (both coding and non-coding regions), we can make estimates of total differences by extrapolation from the differences in known sequences.
Whether this is an improvement or not is arguable, given the recent findings about the importance of "pseudo-genes".
Earthborn
18th May 2003, 08:01 PM
I have studied Chimpanzees in Gombe.Wow! Who would have thought? Genghis Pwn is actually... Jane Goodall!
Welcome to the board, Jane. :)
Shane Costello
19th May 2003, 03:35 AM
A little more on FOXP2:
www.wellcome.ac.uk/en/genome/genesandbody/hg05f004.html
www.cnn.com/2002/TECH/science/08/15/coolsc.speech/
A couple of changes in one gene about 200,000 years ago may be the reason apes still pound the ground -- and humans can recite poetry to communicate.
They discovered a slight amino acid change in the human protein, which was not found in any of the other animals. That change may be a big reason humans developed the face and jaw structures, which make the profound capabilities of speech and language possible.
There are not that many differences between the DNA of a human and a chimp, or even between a human and a whale. But, as knowledge of FOXP2 is revealing, even a tiny number of DNA mutations -- can lead to hugely important physical differences.
Genghis Pwn
19th May 2003, 03:54 AM
Originally posted by Earthborn
Wow! Who would have thought? Genghis Pwn is actually... Jane Goodall!
Welcome to the board, Jane. :)
Hehe. Jane is my hero. :D
Always Free
19th May 2003, 04:07 AM
Shane Costello--
"Nature published an article a few months ago detailing how a few base pair changes between in the same gene between humans and apes has allowed human jaw structure develop into a form capable of articulating speech."
How much of a role does the jaw play in speech though? The voice box and tongue are very necessary for speech but you can talk without moving your jaw.
BillyJoe
19th May 2003, 05:35 AM
Originally posted by Dymanic
I think Gould said that there is more variation in some groups of chimpanzees than there is in the entire human population worldwide. The way I remember it.....
"There is more variation within an ethnic group than between ethnic groups (of humans)"
But it could be an entirely different quote of course.
Shane Costello
19th May 2003, 05:58 AM
Originally posted by Always Free
How much of a role does the jaw play in speech though? The voice box and tongue are very necessary for speech but you can talk without moving your jaw.
The role of the FOXP2 gene was first identified in a family with a history of severe speech impediment. From the Wellcome link:
Unlike all the other families with speech and language disorders that Professor Monaco’s group was studying at the time – in which the disorder is inherited in a complicated way due to the interplay of many different genetic factors – the KE family’s disorder was inherited in a simple fashion and as the result of a defect in a single gene.
About half the family, which spans three generations, suffer from the disorder.
“They have trouble controlling fine movements in the lower half of their face, and this gives them problems when making the complicated sounds necessary for speech,” explains Dr Fisher. In addition to this problem, they have a variety of problems in both spoken and written language and grammar. “For example,” says Dr Fisher, “if you ask them to write down as many words as they can think of beginning with a particular letter, they don’t do very well – and that defect is clearly not related to articulation.”
So the FOXP2 gene isn't just involved in jaw structure, but appears to have a role in formulation of speech. Yes, you can speak without using your jaw, but don't bet on making yourself that well understood.
The Fool
19th May 2003, 09:33 PM
Originally posted by Shane Costello
In the case of cattle (I work in the field of bovine genetics) the current estimate is that the bovine and human genome are 95% similar.
Mooooooooo!
Dymanic
20th May 2003, 10:13 AM
This just in:
Chimps are human (http://www.newscientist.com/news/news.jsp?id=ns99993744)
The latest twist in the debate over how much DNA separates humans from chimpanzees suggests we are so closely related that chimps should not only be part of the same taxonomic family, but also the same genus.
The new study found that 99.4 percent of the most critical DNA sites are identical in the corresponding human and chimp genes. With that close a relationship, the two living chimp species belong in the genus Homo, says Morris Goodman of Wayne State University in Detroit.
athon
21st May 2003, 01:21 AM
Originally posted by BillyJoe
Alfie,
Pretty damn important don't you think?
Actually I think that 96% figure includes junk DNA (non-functional DNA). Junk DNA comprises about 95% of the total but this figure may be way out because some of the junk DNA could turn out to have a function after all. If it's a true figure, however, and the difference (4%) between human and ape DNA is in the functional DNA only, then the difference is pretty substantial.
Hell, it better be!
regards,
BillyJoe
Sorry to be picky Billy, but for some reason this always bugged me.
There is no such thing, really, as junk DNA. At least, not in the past five years. Most introns and exons are showing to have non-coding DNA - its purpose is any number of physical properties, some as simple as mere protection during replication, others as complicated as directing proteins during protein synthesis.
In truth, we have a great deal of coding in common with most animals.
The two 'most different' organisms on the planet are two types of bacteria.
Athon
BillyJoe
21st May 2003, 05:30 AM
Originally posted by athon
There is no such thing, really, as junk DNA. Seems you're right......
"Junk DNA" (http://www.psrast.org/junkdna.htm)
So much so that it is now referred to as non-coding DNA instead of Junk DNA as articpenguin stated above.
Some studies have found that noncoding DNA plays a vital role in the regulation of gene expression during development
Over 700 studies have demonstrated the role of non-coding DNA as enhancers for transcription of proximal gene
Over 60 studies have demonstrated the role of non-coding DNA as silencers for suppression of transcription of proximal genes
Some studies indicate that non-coding DNA regulate translation of proteins
DrMatt
21st May 2003, 01:23 PM
Originally posted by BillyJoe
....evolution did not have much work to do to get from a chimpanzee to homo sapiens. ;)
Alert!
Our cousins are not our grandparents...
DrMatt
21st May 2003, 01:25 PM
Originally posted by Dymanic
This just in:
Chimps are human (http://www.newscientist.com/news/news.jsp?id=ns99993744)
Uh, yeah, that's a taxonomic naming issue, mostly. Life happens and has happened without any regard for our taxonomic naming conventions.
hgc
21st May 2003, 02:11 PM
Originally posted by Dymanic
There is in fact less actual genetic difference between, say the shortest, blackest Pigmy and the tallest, blondest German, than we would expect (or so say some geneticists). It has been suggested (though it is still far from well-established) that the human population passed through a 'bottleneck' around 74k years ago--possibly the result of a 'volcanic winter'. I think Gould said that there is more variation in some groups of chimpanzees than there is in the entire human population worldwide.
The physical characteristics you can see with your eyes are a convenient way for us define genetic disparity, but that's only because we're not well equipped to detect other characteristics of disparity. A Llasa Apso and a Wolf are really, really closely related, and look at how different they appear.
Dymanic
21st May 2003, 04:32 PM
Originally posted by DrMatt
Uh, yeah, that's a taxonomic naming issue, mostly. Life happens and has happened without any regard for our taxonomic naming conventions.
They aren't just suggesting moving the line of distinction (which, I agree is mostly arbitrary)--they're basing it on their studies showing the genetic makeup of humans and chimps having more in common than previously thought. A lot more:
The new study found that 99.4 percent of the most critical DNA sites are identical in the corresponding human and chimp genes.
So now we're down to a .6% difference between the two species, which leaves me still wondering then how much difference there is between the two most genetically distant humans.
Originally posted by hgc
The physical characteristics you can see with your eyes are a convenient way for us define genetic disparity, but that's only because we're not well equipped to detect other characteristics of disparity. A Llasa Apso and a Wolf are really, really closely related, and look at how different they appear.
That's my point exactly. But also, you would expect to see a certain amount of variation, and in humans this is said to be less than what you would expect.
Meet the new member of the family:
http://news.bbc.co.uk/1/hi/sci/tech/3042781.stm
-----------------------------------------------------------------
quote
Not all scientists will accept the new classification.
Whereas Dr Wildman's team find that chimps and humans are 99.4% similar, other researchers last year put the similarity at around 95%; the figure you get depends on precisely which genetic differences you look at.
As to whether this will improve the lot of chimpanzees themselves, a spokeswoman for the conservation group the Jane Goodall Foundation was sceptical.
-----------------------------------------------------
Thanks,
S&S
athon
22nd May 2003, 01:15 AM
As I stated before, the two most different organisms on the planet, genetically speaking, are two bacteria.
So much for the assumptions of genetics equalling perceived differences. It's asked what could 4% (or 0.4%, whichever you believe) difference in genetic makeup achieve. A lot, if you take into account that most of them aren't direct coding genes, but 'switches', 'alternators', 'regulators' and 'manipulators'. In other words, we have many genes that could potentially make us more 'chimp-like'. Or vice versa. The difference is in whether - and in what capacity - they are used.
We all could be hairy with flat noses and large irises - it's in the regulation that makes all the difference.
Athon
BillyJoe
22nd May 2003, 05:13 AM
Originally posted by DrMatt
Our cousins are not our grandparents... Yeah, common ancestry.
(I suppose a humorous post should be accurate as well)
CWL
22nd May 2003, 07:57 AM
Originally posted by BillyJoe
This might help (http://www.wasdarwinright.com/DNArelatedness.html#Comparing%20DNA)
Hmmm. That site appears to be pro creationist (http://www.wasdarwinright.com/). I'd look elsewhere.
Paul C. Anagnostopoulos
22nd May 2003, 10:00 AM
Shane said:So the FOXP2 gene isn't just involved in jaw structure, but appears to have a role in formulation of speech.
Is that just the coolest thing or what?! A gene that plays a role both in thinking about speech and in uttering it. How can you not love this evolution thing?
Noncoding DNA seems to be a lot like dark matter. There's a big bunch of it, but what does it do?
~~ Paul
BillyJoe
23rd May 2003, 03:59 AM
Originally posted by CWL
Hmmm. That site appears to be pro creationist (http://www.wasdarwinright.com/). I'd look elsewhere. Yeah, just testing.
(I think the quote is factual though)
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