4 ms·

We do, but it’s messy and usually involves a few years of courtship, followed by one to three decades of raising & educating the resulting human to anything res

by bgun 2y ago

We do, but it’s messy and usually involves a few years of courtship, followed by one to three decades of raising & educating the resulting human to anything resembling a useful model for comparison.

gcr 2y ago
No, the claim is much stronger than that: that the zygote itself encodes necessary information that isn’t captured in DNA. Put another way, long after humans are extinct, the claim is that if aliens could download our DNA source code somehow, they still wouldn’t be able to build humans without replicating the zygote’s internal structures exactly. We’d come out as super deformed or something. The claim is biological, not sociological.
- shepherdjerred 2y ago
  e.g. imagine being given some source code and being told to compile/execute it but you're not given any hardware.
  - tsimionescu 2y ago
    Not only that, but you're not even given the compiler. If all you have is the DNA (even if you had the mitochondrial DNA too), you have source code for a language no one knows with no compiler. Or, more accurately, it's like having binary machine code for an unknown ISA with no information about the CPU, and no example CPU.
    - ekimekim 2y ago
      Well based on compiler bootstrapping techniques, it seems the solution is simple: Start by hand-assembling the most basic RNA life, then run each step of evolution in sequence. All you need is the DNA (and know the living conditions) of every single organism between single-celled organisms and a modern human.
- Thiez 2y ago
  Perhaps the first generation would be deformed but second-gen (if they hypothetically get that far) should be much closer. You still need the mitochondrial DNA as well.
  - tsimionescu 2y ago
    Well, first of all, they wouldn't be able to build a single functioning cell if all they had was DNA (and even if they had mitochondrial DNA too). Most organelles divide independently of the nucleus, and there is no reason to think that DNA encodes anything about their fundamental structure. Even if some changes in genes can effect some changes in the organelles, that doesn't mean that the genes specify every detail of the organelle. Also, even if we accepted that DNA fully specifies how a cell can create an identical copy of the cell that contains it, that doesn't mean that it specifies how to create a cell from scratch. The "instructions" in DNA could very well depend critically on details of the current cell. For example, the DNA could specify se thing like "take 1% of the substance secreted in organelle A and mix it with 90% water and 9% the substance secreted by organelle B". This instruction is perfectly good for specifying a copy of the current cell, and perfectly useless if you don't have the original cell for which it is meant. This sort of thing could very well apply at the level of the whole fetus. Details of the uterus and other parts of the mother organism may well be critical parts of the "program" described by the DNA. For example, it's easy to imagine that the early fetus follows instructions like "let this much fluid pass through the umbilical chord", or "grow horizontally until you find this much pH difference between the extremeties" or whatever other instructions that are only useful in the context of an existing functioning mother organism. And even beyond the individual, you would have a big problem recreating the species to allow for a second generation to exist at all. In particular, even if you had a whole living healthy female mammal, you would have no information at all for how to create a male of the species, so no way to create sperm cells, so no way to perpetuate the species. So the DNA of a female mammal doesn't contain information for how to make more of the species. And if all you had was a male organism, you would lack the information probably encoded in the living female that I was discussing earlier. As a side note, this problem would not exist for birds, where the female bird does have both male and female DNA.

by bgun 2y ago

gcr 2y ago

No, the claim is much stronger than that: that the zygote itself encodes necessary information that isn’t captured in DNA. Put another way, long after humans are extinct, the claim is that if aliens could download our DNA source code somehow, they still wouldn’t be able to build humans without replicating the zygote’s internal structures exactly. We’d come out as super deformed or something. The claim is biological, not sociological.

shepherdjerred 2y ago
e.g. imagine being given some source code and being told to compile/execute it but you're not given any hardware.
- tsimionescu 2y ago
  Not only that, but you're not even given the compiler. If all you have is the DNA (even if you had the mitochondrial DNA too), you have source code for a language no one knows with no compiler. Or, more accurately, it's like having binary machine code for an unknown ISA with no information about the CPU, and no example CPU.
  - ekimekim 2y ago
    Well based on compiler bootstrapping techniques, it seems the solution is simple: Start by hand-assembling the most basic RNA life, then run each step of evolution in sequence. All you need is the DNA (and know the living conditions) of every single organism between single-celled organisms and a modern human.
Thiez 2y ago
Perhaps the first generation would be deformed but second-gen (if they hypothetically get that far) should be much closer. You still need the mitochondrial DNA as well.
- tsimionescu 2y ago
  Well, first of all, they wouldn't be able to build a single functioning cell if all they had was DNA (and even if they had mitochondrial DNA too). Most organelles divide independently of the nucleus, and there is no reason to think that DNA encodes anything about their fundamental structure. Even if some changes in genes can effect some changes in the organelles, that doesn't mean that the genes specify every detail of the organelle. Also, even if we accepted that DNA fully specifies how a cell can create an identical copy of the cell that contains it, that doesn't mean that it specifies how to create a cell from scratch. The "instructions" in DNA could very well depend critically on details of the current cell. For example, the DNA could specify se thing like "take 1% of the substance secreted in organelle A and mix it with 90% water and 9% the substance secreted by organelle B". This instruction is perfectly good for specifying a copy of the current cell, and perfectly useless if you don't have the original cell for which it is meant. This sort of thing could very well apply at the level of the whole fetus. Details of the uterus and other parts of the mother organism may well be critical parts of the "program" described by the DNA. For example, it's easy to imagine that the early fetus follows instructions like "let this much fluid pass through the umbilical chord", or "grow horizontally until you find this much pH difference between the extremeties" or whatever other instructions that are only useful in the context of an existing functioning mother organism. And even beyond the individual, you would have a big problem recreating the species to allow for a second generation to exist at all. In particular, even if you had a whole living healthy female mammal, you would have no information at all for how to create a male of the species, so no way to create sperm cells, so no way to perpetuate the species. So the DNA of a female mammal doesn't contain information for how to make more of the species. And if all you had was a male organism, you would lack the information probably encoded in the living female that I was discussing earlier. As a side note, this problem would not exist for birds, where the female bird does have both male and female DNA.