• Question: If there is a 2%-3% difference between chimpanzee's and humans what makes them different? (What is in that 2%-3% difference?)

    Asked by to James, Natalie, Shaylon on 26 Jun 2014. This question was also asked by .
    • Photo: Shaylon Stolk

      Shaylon Stolk answered on 26 Jun 2014:

      Great question!
      As it turns out, a lot of our DNA codes for very basic functions that are common to many organisms. That’s why we share 50% of our genetic material with bananas (so your smoothie is 50% cannibalism). So a good deal of that 97% has to do the fact chimps and humans are both apes– so those genes code for having two eyes, five fingers, etc.

      When you’re talking about DNA, 3% is actually a *lot* of genes. For example, a change in one ‘base pair’ in one segment of a gene is the difference between someone having normal red blood cells and having hereditary anemia! (That’s 1/3-billionth of a genome!). So the genes for facial structure, foot structure, and hair distribution are different in humans and chimps, as well as a lot of more subtle traits.

    • Photo: James Bell

      James Bell answered on 26 Jun 2014:

      That is an excellent question – if you asked a geneticist, they could probably give you a 1000 page answer but I’ll try a shorter one than that 😛

      Your genetic makeup (genome) plus which of those genes you actually express (transcriptome) make up a lot of your physical appearance and behaviour (phenotype). Although there might be a tiny difference in our genomes, it doesn’t need to be much to make obvious differences between species and it isn’t the only important difference.

      Some of the genes that make the difference in genomes of chimps and people will be the same genes but just modified a bit (e.g. we both have hair, but humans much much less than chimps). Genes usually code for the production of things like enzymes and hormones which in turn influence our bodies (in digestion, growth etc.) but our environment is also very important to our development

      There are of course some genes unique to humans (because that’s how we are a different species) but the reason the similarity can still be so high is because it’s not just your genome that makes up the difference. Speciation is a complicated process and can occur through genetic, geographic and behavioural reasons. We are genetically isolated from chimps to some extent but we are also very behaviourally isolated. The complexity of human social interactions is one of the things that makes us really different.

    • Photo: Natalie Pilakouta

      Natalie Pilakouta answered on 26 Jun 2014:

      That’s a great question and Shaylon and James already gave you great answers. I just wanted to point out that sometimes the percentage of genetic similarity is very misleading when you try to determine how related two species are. For example, both chickens and fruit flies share about 60% of their genes with humans but we are much more closely related to chickens than to fruit flies.

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