3 ms·

I can absolutely appreciate that we are a series of mutations. To say that there is no benefit or detriment to having an arched nose or not also seems naive. I

I can absolutely appreciate that we are a series of mutations. To say that there is no benefit or detriment to having an arched nose or not also seems naive. It’s likely that the shape of your nose can affect how much air passes to your lungs, how likely it is to be sun burnt or not, and many other things. Just because the values or benefits might be minuscule compared to other things doesn’t mean they do not exist. Tiny optimizations are common in all systems and they should not be overlooked. To say that massive portions of our DNA “have no benefit” without having proof of such, seems naive to me. It’s ok for others to disagree; clearly the majority of the scientific community does. It’s just unfortunate that we have been ignoring the possibility that this large portion of our DNA could have effects on our system. In the article above, it’s not benefits that matter but risks. We shouldn’t only care about parts of our body that may bring benefit but also those which may harm us. As far as baldness goes, this is a trait that could be seen as a benefit. Some females may desire a mate with high levels of DHT and baldness is a good indicator that a being has high levels. There are many visual traits (see birds) that allow the narrowing of selection for potential mates.

cyphar 7y ago
Evolution is not a process of finding a global optimum, just a local one. And traits which have no impact on the chance for a species to reproduce just get carried along for the ride. An obvious example of this is the Laryngeal nerve. Fish evolved with this nerve being a simple straight line between the brain and larynx. However, in animals which evolved from fish and have necks, we see that the nerve is "trapped" under the aortic arch in the thorax. So this nerve ends up looping through your neck to reach your thorax. Giraffes have this nerve going all the way down their neck and back up again. But this inefficiency has no impact on the survival chances of a species (if your neck is severed you're dead regardless of whether you have an additional nerve running through it) so it's stuck around. So, there definitely are traits which objectively have no benefit or detriment and have just stuck around. You could argue even some late-life conditions which are detrimental also "stuck around for the ride" because people late in life don't reproduce and thus there is no evolutionary mechanism to affect such traits.
- dkoston 7y ago
  Sure, I even made this point when I pointed out that the appendix has gotten carried along for the ride in another comment. Do you really believe that 75-98.8% of our DNA serves no purpose and is being carried along for the ride? That doesn't seem like a small inefficiency.
  - cf498 7y ago
    Why would you assume a high grade of efficiency, let alone perfection?
    - dkoston 7y ago
      I’m assuming more than 2% efficiency would be achieved. I could be wrong but why would I assume that when most other systems in the body are massively more efficient that DNA would be the outlier?
klmr 7y ago
> To say that massive portions of our DNA “have no benefit” without having proof of such, seems naive to me. What makes you think scientists have no proof? The whole reason we know junk DNA has no important function for cell biology is that there’s good evidence that says so. There’s some wiggle room with the details but the general picture of this won’t change, and this has been studied for a long time and is fairly well understood.
- dkoston 7y ago
  Whole genome sequencing on humans has only existed for 16 years (1). In 2003, the cost was prohibitive until NGS (next generation sequencing) techniques became commercialized. We can definitely disagree here as 15 years of research which in my worldview is focused mostly on coding DNA and karyotyping doesn’t seem like much to draw this conclusion. There’s plenty of decades old science that has shifted or been rewritten due to the rise of new techniques related to faster computing power. It’s quite possible that I’m biased based on the labs I’m familiar with and papers I’ve been reading. I just haven’t seen the focus that you are talking about. 1 https://www.yourgenome.org/facts/timeline-history-of-genomics https://www.yourgenome.org/facts/timeline-history-of-genomic...
  - klmr 7y ago
    Junk DNA has already been studied before whole-genome sequencing existed, and evidence from NGS not only hasn’t overturned that research, it has largely corroborated it. And as for personal biases, I’m a staunch defender of the ENCODE research so I’m certainly not biased in favour of the concept of junk DNA.
    - dkoston 7y ago
      Interesting. I may be biased in the other direction after reading "The Epigenetics Revolution" and "Junk DNA" by Nessa Carey. ENCODE is such an amazing project! Also, thanks for your research on non coding DNA.

cyphar 7y ago

Evolution is not a process of finding a global optimum, just a local one. And traits which have no impact on the chance for a species to reproduce just get carried along for the ride. An obvious example of this is the Laryngeal nerve. Fish evolved with this nerve being a simple straight line between the brain and larynx. However, in animals which evolved from fish and have necks, we see that the nerve is "trapped" under the aortic arch in the thorax. So this nerve ends up looping through your neck to reach your thorax. Giraffes have this nerve going all the way down their neck and back up again. But this inefficiency has no impact on the survival chances of a species (if your neck is severed you're dead regardless of whether you have an additional nerve running through it) so it's stuck around. So, there definitely are traits which objectively have no benefit or detriment and have just stuck around. You could argue even some late-life conditions which are detrimental also "stuck around for the ride" because people late in life don't reproduce and thus there is no evolutionary mechanism to affect such traits.

dkoston 7y ago
Sure, I even made this point when I pointed out that the appendix has gotten carried along for the ride in another comment. Do you really believe that 75-98.8% of our DNA serves no purpose and is being carried along for the ride? That doesn't seem like a small inefficiency.
- cf498 7y ago
  Why would you assume a high grade of efficiency, let alone perfection?
  - dkoston 7y ago
    I’m assuming more than 2% efficiency would be achieved. I could be wrong but why would I assume that when most other systems in the body are massively more efficient that DNA would be the outlier?

klmr 7y ago

> To say that massive portions of our DNA “have no benefit” without having proof of such, seems naive to me. What makes you think scientists have no proof? The whole reason we know junk DNA has no important function for cell biology is that there’s good evidence that says so. There’s some wiggle room with the details but the general picture of this won’t change, and this has been studied for a long time and is fairly well understood.

dkoston 7y ago
Whole genome sequencing on humans has only existed for 16 years (1). In 2003, the cost was prohibitive until NGS (next generation sequencing) techniques became commercialized. We can definitely disagree here as 15 years of research which in my worldview is focused mostly on coding DNA and karyotyping doesn’t seem like much to draw this conclusion. There’s plenty of decades old science that has shifted or been rewritten due to the rise of new techniques related to faster computing power. It’s quite possible that I’m biased based on the labs I’m familiar with and papers I’ve been reading. I just haven’t seen the focus that you are talking about. 1 https://www.yourgenome.org/facts/timeline-history-of-genomics https://www.yourgenome.org/facts/timeline-history-of-genomic...
- klmr 7y ago
  Junk DNA has already been studied before whole-genome sequencing existed, and evidence from NGS not only hasn’t overturned that research, it has largely corroborated it. And as for personal biases, I’m a staunch defender of the ENCODE research so I’m certainly not biased in favour of the concept of junk DNA.
  - dkoston 7y ago
    Interesting. I may be biased in the other direction after reading "The Epigenetics Revolution" and "Junk DNA" by Nessa Carey. ENCODE is such an amazing project! Also, thanks for your research on non coding DNA.