Question: this really confuses me.... why do apes (i think) have 24 chromosomes, whilst humans only have 23? something like that????

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  1. Humans and apes are very genetically similar, but this doesn’t mean we need to have the same number of chromosomes.

    There is evidence to suggest that human chromosome 2 was made from two ape chromosomes fusing together, which would explain why humans have one less pair (the chromosomes come in pairs. We have 23 pairs: two copies of chromosome 1, two copies of chromosomes 2….etc).

    Because the chromosomes fused, rather than being lost or destroyed, then all the genetic information that was on each of the ape chromosomes should still be present in humans. Of course, since humans and apes became different species there have been further changes, so there are definitely differences between us.

    If you’re asking the question because you think more chromosomes = more intelligent, then that is not the case! Some plants have hundreds of chromosomes, and chickens, goldfish and silk worms all have more than humans do.

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  2. Aimee’s right. There are different numbers of chromosomes in different species, and the number of chromosomes has nothing to do with how advanced or intelligent a species is.

    Chromosomes are made up of DNA, which contains the genes that code all the characteristics and processes in a plant or animal. Sections of DNA sometimes have the amazing ability to “jump” from one place to another when cells are dividing or when sperm and egg cells are being made.

    These jumping pieces of DNA can sometimes have big consequences and rearrange big sections of chromosomes. It might mean that a whole chromosome gets lost because all the important genes on it have jumped to other chromosomes. On the other hand, one chromosome might get split into two different new chromosomes.

    While apes and humans are relatively closely related (we share at least 96% of our DNA), it has still been 4-8 million years since the common ancestor to which we are both related existed. That’s a lot of time for jumping DNA to make big changes to the chromosomal rearrangement of our genes.

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  3. Great answers. It’s not what you got, it’s what you do with it. I guess we ought to mention that a lot of DNA looks to be junk – stuff that’s kind of built up over millions of years but doesn’t do anything. We could probably get rid of a lot of the DNA and keep all the useful stuff, but then we’d have to change a bunch of other things about how cells work and it’s all too much effort. So we live with 3 billion bits of information making up our genes when we could use a lot less.

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  4. I don’t know but I’m glad Aimee and Bridget have answered this.

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  5. Don’t know. This is outside my area of knowledge.

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