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I think you need to learn more about the immune system. But to continue your analogy, it doesn't need to be a two-step process. You can start with an immune sy

I think you need to learn more about the immune system. But to continue your analogy, it doesn't need to be a two-step process. You can start with an immune system and "randomly marked" cells (they're not random, but say they are). Millions of cells are created by your body every second. The cells that are marked "incorrectly" will die off, leaving those the immune system recognizes to continue reproducing. Overtime the remaining cells DNA will only contain instructions to create new cells "marked" to not provoke an immune response. Why is one such counterexample so unthinkable a process to you?

deleted 4y ago
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remote_phone 4y ago
No because the immune system would have to know to rely on the fact that the markings are different across every single cell in the body. Until they were all exactly the same, the immune system couldn’t switch over to relying on this. Entire organs not just cells would die. It needs changes in two separate systems, the cellular system and the immune system, and it has to occur randomly.
- stevenhuang 4y ago
  > because the immune system would have to know to rely on the fact that the markings are different across every single cell in the body You are confused because you are looking at the final result and not how the system came about. The two systems can be randomly initialized and it will all converge together to a working system over time. And again one can bet it's not really random, aspects of DNA "initialization" happen even before gestation (mitosis) phase. And then during fetus growth all of this can still be developed independently and converge over time. I am speaking from a layman's perspective and even I can surmise many such counterexamples that may explain how the immune system came to be. I again reiterate that you seem to be operating on an incomplete understanding of not just the immune system, but how evolution and embryonic development works. You may want to read this: https://www.nature.com/articles/s41390-022-01940-0 https://www.nature.com/articles/s41390-022-01940-0 > The initiation of hematopoiesis from the yolk sac of human embryo, formation of the bone marrow, and all the immune cells produced from it begins at 5 weeks of gestation, which stimulate mass production of immune cells in the following weeks to boost the immune system

deleted 4y ago

[deleted]

remote_phone 4y ago

No because the immune system would have to know to rely on the fact that the markings are different across every single cell in the body. Until they were all exactly the same, the immune system couldn’t switch over to relying on this. Entire organs not just cells would die. It needs changes in two separate systems, the cellular system and the immune system, and it has to occur randomly.

stevenhuang 4y ago
> because the immune system would have to know to rely on the fact that the markings are different across every single cell in the body You are confused because you are looking at the final result and not how the system came about. The two systems can be randomly initialized and it will all converge together to a working system over time. And again one can bet it's not really random, aspects of DNA "initialization" happen even before gestation (mitosis) phase. And then during fetus growth all of this can still be developed independently and converge over time. I am speaking from a layman's perspective and even I can surmise many such counterexamples that may explain how the immune system came to be. I again reiterate that you seem to be operating on an incomplete understanding of not just the immune system, but how evolution and embryonic development works. You may want to read this: https://www.nature.com/articles/s41390-022-01940-0 https://www.nature.com/articles/s41390-022-01940-0 > The initiation of hematopoiesis from the yolk sac of human embryo, formation of the bone marrow, and all the immune cells produced from it begins at 5 weeks of gestation, which stimulate mass production of immune cells in the following weeks to boost the immune system