How much different are the DNA of chimps and humans.

[heliocentricprose]

How much different are the DNA of chimps and humans. I've read in a magazine that it is 98-99 percent. But, my friend tells me 95%. Who is right? And what is the difference between 98 and 95 percent in terms of the quantity of genetic code?

 

[selfAdjoint]

It depends on what technology to measure. The old method which was based, roughly, on the tendency of DNA strands from the two species to stick together, gave a very high value, sometimes over 99%. Since both genomes have been sequenced, it's possible to do a more precise comparison, and that produces the lower figure.

But in thinking about this issue, you have to remember that the great majority of our genes go to make us metazoans (we share 35% of our genes with Oak trees (old method)), then chordates, then mammals, and only a tiny proportion are what makes us primates, much less humans.

 

[PIT2]

This was news yesterday:

Most of the big differences between human and chimpanzee DNA lie in regions that do not code for genes, according to a new study. Instead, they may contain DNA sequences that control how gene-coding regions are activated and read.

"The differences between chimps and humans are not in our proteins, but in how we use them," said Katherine Pollard, assistant professor at the UC Davis Genome Center and the Department of Statistics.
http://www.sciencedaily.com/releases/2006/10/061013104633.htm

 

[Phobos]

I've seen numbers cited from 95-99% too (so you're both "right") but like selfAdjoint said, it depends on how it was measured. The more important points are that (1) we are genetically more similar to chimps than to any other species; (2) we are VERY similar (e.g., Jarod Diamond's book "The Third Chimpanzee" reported that some subspecies of other animals are more different to each other than humans are to chimps); and (3) the genetic similarities all fit in with the theory of common descent.