Human vs chimp

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Fion

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Chinese
Reich's team also found that the entire human X chromosome diverged from the chimp's X chromosome about 1.2 million years later than the other chromosomes.

I want to ask......
Does this sentence mean that human and chimps are the same X chromosome at first, and then after 1.2 million human X chromosome differ from chimp's X chromosome???
 
  • Reich's team also found that the entire human X chromosome diverged from the chimp's X chromosome about 1.2 million years later than the other chromosomes.

    I want to ask......
    Does this sentence mean that human and chimps are the same X chromosome at first, and then after 1.2 million human X chromosome differ from chimp's X chromosome???
    It basically means what you said. The X chromosome from humans and chimps had been relatively the same for 1.2 million years while the other X and Y chromosomes from humans had already diverged from chimpanzees.

    It's really a scientific question so I'll try and explain it that way, too.

    99.9% of human and chimp DNA is alike. There is only one percent of human DNA that makes us humans, not chimpanzees. This must imply that humans either evolved from the same ancestor as chimpanzees or evolved from chimpanzees. Probably from chimpanzees since the genomes are so similar.

    Humans have either two X chromosomes (women) or one X chromosome and one Y chromosome (men). I assume the article is talking about the X chromosome that is common in both men and women.

    Throughout time DNA changes because of mutation or what not and then if it's a good trait, natural selection will keep it in the genome.

    The shocking thing about this find is that Humans and chimps appear to have diverged much later than originally thought. 1.2 million years later than the other chromosomes is a long time for divergence. Apparently these other chromosomes had already diverged while this chromosome remained relatively the same. This could be due to interbreeding, where human and chimp chromosomes diverged at first, but then got mixed again, until finally the interbreeding stopped and they were sufficiently diverged millions of years later. Some of the species thought to be human ancestors may be, in fact, hybrids of humans and chimpanzees.
     

    Fion

    New Member
    Chinese
    Sorry, I felt a little confused. Allow me to explain my view in this way. I hope you can correct my view. Human X chromosome and chimpanzee X chromosome are the same at first. Human X chromosome is different from chimpanzee X chromosome after 1.2 million owing to interbreeding. But why did you mention Y chromosome? (The X chromosome from humans and chimps had been relatively the same for 1.2 million years while the other X and Y chromosomes from humans had already diverged from chimpanzees. ) I saw the article saying as follows. Reich’s team also found that the entire human X chromosome diverged from the chimp’s X chromosome about 1.2 million years later than the other chromosomes. One plausible explanation is that chimps and humans first split but later interbred from time to time before finally going their separate evolutionary ways. That could explain why some of the most ancient fossils now considered human ancestors have such striking mixtures of chimp and human traits – some could actually have been hybrids. Or they might have simply co-existed with, or even predated, the last common ancestor of chimps and humans.
    Question 2: “One plausible explanation is that chimps and humans first split but later interbred from time to time before finally going their separate evolutionary ways,” quoted from above. What does it mean that chimps and humans first split? Does that mean human X chromosome is different from chimps’ X chromosome at first, which is opposite from what I said in the beginning.?
     

    panjandrum

    Occasional Moderator
    English-Ireland (top end)
    This thread stopped being about English and started being about genetics early in post #2. As this is a forum for discussion of English, the thread is now closed.
     
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