Human and Animal Genes

[kmguru]

I am sure we have debated about this before. I have a simple question.

It is said that Humans and Chimpanzees have 96% (some say 98%) same genes.

Is the statement true?
This percentage is based on what?
The count is based on how many genes for the humans? and How many genes for the Chimpanzee? Or the amount is same for both?

What is the total number of genes that ~3 billion base pairs represent for humans? Out of that what is the latest number of protein-coding genes for humans and how that relates to that of Chimpanzees?

The purpose is to get a handle on the above statement like the statement that we use only 10% of our brain capacity insinuated as 90% is a waste.

 

[Fraggle Rocker]

I am sure we have debated about this before. I have a simple question. It is said that Humans and Chimpanzees have 96% (some say 98%) same genes. Is the statement true?

Yes, it is true. I was just at the new, permanent Hall of Human Origins exhibit in the prestigious Smithsonian Institution's National Museum of Natural History. They had a chart showing the percentage of shared genes with a variety of species. As I recall it was a bit higher than 98% for chimpanzees, perhaps closer to 99%, but as you point out recent research has dropped it down closer to 96%. The problem with putting together an exhibit like that is that by the time you open it to the public, some of your data is out of date.

It's somewhere around 95% for mice, and even banana trees have about 45% of our DNA.

This percentage is based on what? The count is based on how many genes for the humans? and How many genes for the Chimpanzee? Or the amount is same for both?

Obviously since they had comparisons for other species that clearly do not have the same number of genes as H. sapiens, they were using some standard statistical normalization algorithm. Big deal! They didn't try to get it down to five-digit precision and say it's 98.762%. It's just a round number for laymen.

What is the total number of genes that ~3 billion base pairs represent for humans? Out of that what is the latest number of protein-coding genes for humans and how that relates to that of Chimpanzees?

You'll have to wait for a real biologist to step in and answer that one. And I don't think biology is a discipline that's very well represented on SciForums. We seem to have more physicists.

The purpose is to get a handle on the above statement like the statement that we use only 10% of our brain capacity insinuated as 90% is a waste.

Well c'mon, Guru. We can count genes, especially now, with DNA-analysis technology so fast, cheap and abundant. You may not approve of the statistical reduction technique they use for comparing two genetic codes that don't have the same number of chromosomes, but at least the numbers they're cranking into their formulas are accurate. The statement that we only use ten percent of our brain is not based on such detailed evidence. It's merely an arm-waving guesstimate, which in fact is no longer being bandied about quite so much as it once was.

 

[kmguru]

We can count the oil leaking in the gulf too....I will wait....

 

[Hercules Rockefeller]

It is said that Humans and Chimpanzees have 96% (some say 98%) same genes.

Is the statement true?

The answer is “it depends”. As you might imagine, comparing whole genomes is a complex scientific endeavour. There are many variables and considerations. So, when comparing together the human and chimp genomes (or any two genomes), the percentage similarity you find depends entirely on those variables and considerations. You can come up with a figure of 98% if you compare the right things within the genomes; you can come up with much less if you compare other things.

This percentage is based on what?

The human and chimp genomes are very similar. This isn’t surprising considering their immediate evolutionary relatedness. The main difference is that humans have one fewer pair of chromosomes than do other great apes. Humans have 23 pairs of chromosomes and other great apes have 24 pairs of chromosomes. In the human evolutionary lineage, two ancestral ape chromosomes fused at their telomeres producing human chromosome 2. Other major differences are chromosomal inversions in various chromosomes.

If you compare protein coding genes only between chimps and humans you will get a very high similarity (~98% or more). Chimp/human proteins are very similar. For instance, about 30% of all human proteins are identical in amino acid sequence to the corresponding chimp protein with only a few synonymous (ie. ‘silent’) base pair changes at the DNA level. Most other proteins differ by only a few amino acids on average.

However, protein coding genes account for <5% of the genome (be it human or chimp). The chimp genome Wikipedia article says that “....24% of the chimpanzee genome does not align with the human genome. There are 3% further alignment gaps, 1.23% SNP differences, and 2.7% copy number variations totaling at least 30% differences between chimpanzee and Homo sapiens genomes.”

So, if you start comparing larger portions of the two genomes rather than just the genes, the % similarity comes down.

The count is based on how many genes for the humans? and How many genes for the Chimpanzee? Or the amount is same for both?

What is the total number of genes that ~3 billion base pairs represent for humans? Out of that what is the latest number of protein-coding genes for humans and how that relates to that of Chimpanzees?

Gene numbers are the same for hominids, save for a few minor differences here and there. The number continually changes as the genome sequences are refined and analyzed. The number will continue to be an estimate for some time as the total number is still based on computer algorithms that predict genes from total genome sequences. I think the number stands somewhere between 25000-30000 genes.

 

[Michael]

Just so we're all clear, we (and chimps, dogs, worms, etc....) use all of our brain. We may not use it to it's full potential in the sense that we could be "thinking" about "important" stuff, but, nevertheless we're using it. And, funny enough, when we're stairing into space not consciously thinking, THEN we're really us it! Something like 20x increase in glucose metabolism.