4 ms·

To what extent do genes encode the facial features that make them distinctly recognizable to us? Is there a way to say it as a "%"? I can certainly see how yo

To what extent do genes encode the facial features that make them distinctly recognizable to us? Is there a way to say it as a "%"? I can certainly see how your basic head size/shape and position of nose/mouth/eyes, etc is baked in there somehow. But I'd love to know, the fundamentals of why you look like your parents, what is that? Certain (75%?) placement of facial features locked in by genes, so of course you look like them, but then the last 25% up to developmental noise? (Example -- fingerprints, almost completely determined by developmental noise, right?)

BurningFrog 6y ago
Unless you have some deforming disease, accident or malnutrition, identical twins have very close to identical faces. Identical twins have very similar, but distinguishable fingerprints.
- ashtonkem 6y ago
  Identical twins having extremely similar faces isn’t exactly a great argument for determining facial characteristics via dna, as identical twins also shared the same environment during fetal growth. It’s entirely possible that genetics and developmental experience combined creates facial structure, and that dna alone is insufficient.
  - iguy 6y ago
    I guess you should compare to non-identical twins. Who I think look like siblings who happen to be the same age. But no doubt someone somewhere has tried to quantify this.
  - BurningFrog 6y ago
    Fair point. The only experimental way I can think of checking this is how similar cloned animals are. A quick googling seems to say clones are quite similar, but not really identical. Which I think somewhat contradicts my claim.
- jedimastert 6y ago
  I think "deforming accident" is a lot easier than some might realize. I personally have had an injury that probably changed the shape of my face, and it wasn't super note-worthy. Especially if someone gets something like a broken jaw, you can look almost unrecognizable.
- maceurt 6y ago
  Depending on how you breathe, your posture, how you sit, if you exercised consistently as a child, etc. your face can look completely different. The greatest example of this is how early humans had significantly larger jaws due to their diet and exercise, while humans today who have almost the exact same facial genes have much smaller jaws.
  - nyokodo 6y ago
    The introduction of the fork in the middle ages caused the development of the overbite. https://www.theatlantic.com/health/archive/2013/01/how-forks-gave-us-overbites-and-pots-saved-the-toothless/267252/ https://www.theatlantic.com/health/archive/2013/01/how-forks...
    - est31 6y ago
      Also: sanitation gave us polio: https://nextnature.net/2014/01/how-modern-sanitation-gave-us-polio https://nextnature.net/2014/01/how-modern-sanitation-gave-us...
  - est31 6y ago
    Do you have more reading on that? Especially on the breathing and posture/sitting part.
TheSpiceIsLife 6y ago
Would identical twins suggest the genes encode facial features to a high degree?
- ashtonkem 6y ago
  No, as identical twins also share whatever happened in utero. To draw a strong example, take fetal alcohol syndrome, which often causes facial changes. Two identical twins with FAS will share similar facial changes, but these changes will not actually be encoded in their dna, but instead will be the result of developmental history.
  - kyberias 6y ago
    You keep repeating that DNA doesn't have a strong role in determining what a person looks like. Yet everything we know about development including twin-studies seems to suggest that in fact it has strong role. For example, this scientific article published in Nature opens with this: "The human face is a complex trait under strong genetic control, as evidenced by the striking visual similarity between twins." https://www.nature.com/articles/srep45885 https://www.nature.com/articles/srep45885 These researchers who are _specialists_ on this field have no doubt. Why do you keep casting doubt on this?
liability 6y ago
Identical twins, sharing the same DNA, look rather identical but not truly identical. Even when raised apart. I am skeptical of reconstructing faces from DNA using current knowledge and technology though. It seems theoretically feasible, but I wouldn't bet on this company being able to do it well.
- ponker 6y ago
  Developmental noise will be dominated by fetal development, not life after birth.
  - ashtonkem 6y ago
    Which probably isn’t directly encoded into your dna, but rather epigenetic markers which may or may not be easily collected and quantified.
  - liability 6y ago
    Maybe so, but fathers can look a great deal like sons and they only share something like half their code and don't share a womb at all. Identical twins share their code and look even more alike. I think later life matters like obesity probably make a bigger difference. Being fat or gaunt can dramatically change somebody's appearance. Grooming habits as well. Spies deliberately adopting disguises can make themselves look quite different by modifying these sort of things.
  - asdff 6y ago
    Not necessarily. Fitness, sun, sleep, alcohol, drugs, diet, smoking, and stress are some examples of environmental factors that can influence your appearance including your face after birth.
- bpodgursky 6y ago
  If you were looking for a suspect and the only identification you had was a photo of their identical twin, would you use it? Obviously it's not a perfect match, but it's going to be wildly better than a sketch artist's attempt at a usable drawing.
ponker 6y ago
Probably pretty predictive. Identical twins have different (but correlated) developmental noise and look anything from very similar to totally identical.
tokai 6y ago
Clones from the Dolly sheep were not identical. If I remember correctly it is thought that epigenetics played a role in their differences.
Real_S 6y ago
Yes, it depends on the facial feature, but some parts are fairly highly heritable. https://www.nature.com/articles/srep45885 https://www.nature.com/articles/srep45885

BurningFrog 6y ago

Unless you have some deforming disease, accident or malnutrition, identical twins have very close to identical faces. Identical twins have very similar, but distinguishable fingerprints.

ashtonkem 6y ago
Identical twins having extremely similar faces isn’t exactly a great argument for determining facial characteristics via dna, as identical twins also shared the same environment during fetal growth. It’s entirely possible that genetics and developmental experience combined creates facial structure, and that dna alone is insufficient.
- iguy 6y ago
  I guess you should compare to non-identical twins. Who I think look like siblings who happen to be the same age. But no doubt someone somewhere has tried to quantify this.
- BurningFrog 6y ago
  Fair point. The only experimental way I can think of checking this is how similar cloned animals are. A quick googling seems to say clones are quite similar, but not really identical. Which I think somewhat contradicts my claim.
jedimastert 6y ago
I think "deforming accident" is a lot easier than some might realize. I personally have had an injury that probably changed the shape of my face, and it wasn't super note-worthy. Especially if someone gets something like a broken jaw, you can look almost unrecognizable.
maceurt 6y ago
Depending on how you breathe, your posture, how you sit, if you exercised consistently as a child, etc. your face can look completely different. The greatest example of this is how early humans had significantly larger jaws due to their diet and exercise, while humans today who have almost the exact same facial genes have much smaller jaws.
- nyokodo 6y ago
  The introduction of the fork in the middle ages caused the development of the overbite. https://www.theatlantic.com/health/archive/2013/01/how-forks-gave-us-overbites-and-pots-saved-the-toothless/267252/ https://www.theatlantic.com/health/archive/2013/01/how-forks...
  - est31 6y ago
    Also: sanitation gave us polio: https://nextnature.net/2014/01/how-modern-sanitation-gave-us-polio https://nextnature.net/2014/01/how-modern-sanitation-gave-us...
- est31 6y ago
  Do you have more reading on that? Especially on the breathing and posture/sitting part.

TheSpiceIsLife 6y ago

Would identical twins suggest the genes encode facial features to a high degree?

ashtonkem 6y ago
No, as identical twins also share whatever happened in utero. To draw a strong example, take fetal alcohol syndrome, which often causes facial changes. Two identical twins with FAS will share similar facial changes, but these changes will not actually be encoded in their dna, but instead will be the result of developmental history.
- kyberias 6y ago
  You keep repeating that DNA doesn't have a strong role in determining what a person looks like. Yet everything we know about development including twin-studies seems to suggest that in fact it has strong role. For example, this scientific article published in Nature opens with this: "The human face is a complex trait under strong genetic control, as evidenced by the striking visual similarity between twins." https://www.nature.com/articles/srep45885 https://www.nature.com/articles/srep45885 These researchers who are _specialists_ on this field have no doubt. Why do you keep casting doubt on this?

liability 6y ago

Identical twins, sharing the same DNA, look rather identical but not truly identical. Even when raised apart. I am skeptical of reconstructing faces from DNA using current knowledge and technology though. It seems theoretically feasible, but I wouldn't bet on this company being able to do it well.

ponker 6y ago
Developmental noise will be dominated by fetal development, not life after birth.
- ashtonkem 6y ago
  Which probably isn’t directly encoded into your dna, but rather epigenetic markers which may or may not be easily collected and quantified.
- liability 6y ago
  Maybe so, but fathers can look a great deal like sons and they only share something like half their code and don't share a womb at all. Identical twins share their code and look even more alike. I think later life matters like obesity probably make a bigger difference. Being fat or gaunt can dramatically change somebody's appearance. Grooming habits as well. Spies deliberately adopting disguises can make themselves look quite different by modifying these sort of things.
- asdff 6y ago
  Not necessarily. Fitness, sun, sleep, alcohol, drugs, diet, smoking, and stress are some examples of environmental factors that can influence your appearance including your face after birth.
bpodgursky 6y ago
If you were looking for a suspect and the only identification you had was a photo of their identical twin, would you use it? Obviously it's not a perfect match, but it's going to be wildly better than a sketch artist's attempt at a usable drawing.

ponker 6y ago

Probably pretty predictive. Identical twins have different (but correlated) developmental noise and look anything from very similar to totally identical.

tokai 6y ago

Clones from the Dolly sheep were not identical. If I remember correctly it is thought that epigenetics played a role in their differences.

Real_S 6y ago

Yes, it depends on the facial feature, but some parts are fairly highly heritable. https://www.nature.com/articles/srep45885 https://www.nature.com/articles/srep45885