Human evolution

Human DNA evolution as a “balancing act”

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As described at Eurekalert:

SAN FRANCISCO, CA—January 13, 2023—Humans and chimpanzees differ in only one percent of their DNA. Human accelerated regions (HARs) are parts of the genome with an unexpected amount of these differences. HARs were stable in mammals for millennia but quickly changed in early humans. Scientists have long wondered why these bits of DNA changed so much, and how the variations set humans apart from other primates.

Now, researchers at Gladstone Institutes have analyzed thousands of human and chimpanzee HARs and discovered that many of the changes that accumulated during human evolution had opposing effects from each other.

If humans and chimps differ in only 1% of our DNA, obviously, DNA is not the best place to look for the differences.

The findings, she says, have implications for understanding human evolution. In addition—because she and her team discovered that many HARs play roles in brain development—the study suggests that variations in human HARs could predispose people to psychiatric disease.

Among life forms, psychiatric disease is, pardon us, a high-class worry.

It’s a serious problem, to be sure. But to have it, you have to have a mind. Which sets you apart from trillions of life forms right away. Including chimpanzees. The paper is open access.

7 Replies to “Human DNA evolution as a “balancing act”

  1. 1
    martin_r says:

    HARs were stable in mammals for millennia but quickly changed in early humans

    So molecular clock is not ticking on a constant rate?

    Seversky, Chuckdarwin, JVL could you clarify?

  2. 2
    PyrrhoManiac1 says:

    It’s been known since Ayala’s work in 1999 that lots of factors can affect the reliability of molecular clock models. The models are useful when we’re able to determine which conditions constrain their applicability, and not otherwise — just like in all of science.

  3. 3
    bornagain77 says:

    Sept: 2022 – Genetic Evidence falsifies the claim the humans evolved from apes-like creature. And falsifies it in a ‘hard’ manner.
    https://uncommondescent.com/intelligent-design/at-evolution-news-did-life-first-arise-by-purely-natural-means/#comment-765765

  4. 4
    relatd says:

    Ba77,

    The evidence from some posts here is that without Evolution to act as a force to stop Intelligent Design, ID would spread as the best theory with the best evidence. Like a group of men guarding a building, ID must be countered whenever it makes claims – constantly. It cannot be allowed to enter that building and establish itself. So, as discredited as Evolution is, those who guard it will continue to post things that confuse the issue. As if everything you posted has been called into question, or just to cause confusion among general readers.

    I encourage you to keep up the good work. The other side has been clearly shown to lack credibility.

  5. 5
    jerry says:

    This has been discussed many times before.

    The difference between humans and other species do no lie in the DNA but in gene expression. And it is massive especially in genes encoding for neural adaptations. No way it could have been gradual. Besides gradual always fails because logic refutes it.

    Apparently those on UD are unaware of the research that has been done.

  6. 6
    Fasteddious says:

    In any case, the “1% difference” is not true. It was only true when comparing the parts of the two genomes that overlapped enough to compare. When the entire genomes are compared, the difference is much bigger apparently. Nevertheless, even a small % genetic difference can make a huge physiological difference. Indeed, most of the genome must be similar since, for the most part, there are similar proteins, enzymes, lipids and other building blocks in both species, as partly discussed here: https://thopid.blogspot.com/2019/02/a-junk-dna-functionality-analogy.html

  7. 7
    Querius says:

    Fasteddious @6,

    Thanks for pointing this out. I was pretty surprised when I first learned the putative ~1% difference between the human and chimp genomes was not comparing their entire genomes, but only the portions that were the most similar.

    Thus, by carefully picking the segments to compare, one would also be able to claim that the human and chimp genomes are 100% the same. Eep, eep.

    BUT . . .

    Dr. Richard Buggs, Professor of Evolutionary Genomics, Queen Mary University of London (2018-present) posted this in the journal, Genomics:
    https://richardbuggs.com/2018/07/14/how-similar-are-human-and-chimpanzee-genomes/

    In it, he shows how he was able to estimate the similarity of the chimpanzee and human genomes at about 82-84%.

    -Q

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