3 ms·

Twins share the same environment in the 1st 9 months, when their faces are formed.

kyberias 12y ago
Usually yes but that doesn't change the fact that face features are highly hereditary. I find it very hard to believe that someone could try to deny this. It's basic biology really. What are you suggesting here exactly? What exactly is the environmental trigger in the womb that forms the faces if not genes? May I kindly remind you about the concept of dizygotic twins, that is, twins that share the womb but do not share an identical genome. Please explain why they don't look identical.
- heurist 12y ago
  I'm not saying faces aren't determined by hereditary factors, only that there are also other factors. Almost all of the 'identical' twins I've seen had subtle differences.
  - kyberias 12y ago
    Yet those differences are, as you said, subtle, that is, very small. That means that, in the context of this article, there is no huge range of faces we can determine from genes, but the genes (when we know them) actually determine the face very very precisely as proved by identical-twin-resemblance. The predicted faces in the article are fuzzy not because environment has a great impact but because our knowledge of the genes that form our faces is still very limited.
    - heurist 12y ago
      The differences between twins who grew up together and were exposed to the same environmental effects were subtle, not necessarily so for the difference between a person and a prediction based on their genome. The comparisons of predictions to real faces from the article showed that (so far) predicted faces miss tons of little details that make people recognizable. Genes do not work in a vacuum, different environmental factors can trigger the use of different genes, and many genes are expressed to varying degrees depending on chance. Say one twin grows up in a nutrient-rich environment while another grows up in a nutrient-poor environment. The nutrient-poor twin will most likely have more developmental issues than the nutrient-rich twin, which can have a wide variety of effects. Perhaps a model trained on more data would be more accurate, but I'll believe it when I see it.
      - kyberias 12y ago
        Clearly you're unable to calibrate your stubborn beliefs with the fact that two identical genomes produce identical looking people. That is VERY strong evidence that a person's face is almost 100% determined by genes. Stop hand-waving and study more developmental biology.
        heurist 12y ago
        I'm certainly stubborn, but I'm not the only stubborn one here. Unless you're a biologist I probably know at least as much about genetics as you, so we're working from the same level of knowledge. Look up epigenetics. The real world is not as perfect as textbooks and experiments like to pretend. Additionally, I happen to think a lot about adaptive systems (obsessive levels of thought sometimes) so the idea that systems develop differently when exposed to different stimuli or environments is a given to me. Check this out: http://well.blogs.nytimes.com/2015/03/04/one-twin-exercises-the-other-doesnt/?_r=0 http://well.blogs.nytimes.com/2015/03/04/one-twin-exercises-... They took identical twins who had already grown to adulthood together and analyzed differences between the sibling who exercised a lot and the one who didn't. Guess what: they found differences that a genetic analysis would not predict! It's trivial in my mind that two identical twins who grew up in very different environments would look noticeably different due to developmental differences. I don't even know what you're arguing over, I never said faces are not genetically determined, only that other things also affect it. That would be the reason for that "almost" part of your assertion. I'm saying that difference is not negligible, some people look very similar by chance. A quick search led me to this: http://www.npr.org/blogs/pictureshow/2011/12/26/144282436/the-photographic-fascination-with-twins http://www.npr.org/blogs/pictureshow/2011/12/26/144282436/th... Close, but not identical.

Usually yes but that doesn't change the fact that face features are highly hereditary. I find it very hard to believe that someone could try to deny this. It's basic biology really. What are you suggesting here exactly? What exactly is the environmental trigger in the womb that forms the faces if not genes? May I kindly remind you about the concept of dizygotic twins, that is, twins that share the womb but do not share an identical genome. Please explain why they don't look identical.

heurist 12y ago
I'm not saying faces aren't determined by hereditary factors, only that there are also other factors. Almost all of the 'identical' twins I've seen had subtle differences.
- kyberias 12y ago
  Yet those differences are, as you said, subtle, that is, very small. That means that, in the context of this article, there is no huge range of faces we can determine from genes, but the genes (when we know them) actually determine the face very very precisely as proved by identical-twin-resemblance. The predicted faces in the article are fuzzy not because environment has a great impact but because our knowledge of the genes that form our faces is still very limited.
  - heurist 12y ago
    The differences between twins who grew up together and were exposed to the same environmental effects were subtle, not necessarily so for the difference between a person and a prediction based on their genome. The comparisons of predictions to real faces from the article showed that (so far) predicted faces miss tons of little details that make people recognizable. Genes do not work in a vacuum, different environmental factors can trigger the use of different genes, and many genes are expressed to varying degrees depending on chance. Say one twin grows up in a nutrient-rich environment while another grows up in a nutrient-poor environment. The nutrient-poor twin will most likely have more developmental issues than the nutrient-rich twin, which can have a wide variety of effects. Perhaps a model trained on more data would be more accurate, but I'll believe it when I see it.
    - kyberias 12y ago
      Clearly you're unable to calibrate your stubborn beliefs with the fact that two identical genomes produce identical looking people. That is VERY strong evidence that a person's face is almost 100% determined by genes. Stop hand-waving and study more developmental biology.
      - heurist 12y ago
        I'm certainly stubborn, but I'm not the only stubborn one here. Unless you're a biologist I probably know at least as much about genetics as you, so we're working from the same level of knowledge. Look up epigenetics. The real world is not as perfect as textbooks and experiments like to pretend. Additionally, I happen to think a lot about adaptive systems (obsessive levels of thought sometimes) so the idea that systems develop differently when exposed to different stimuli or environments is a given to me. Check this out: http://well.blogs.nytimes.com/2015/03/04/one-twin-exercises-the-other-doesnt/?_r=0 http://well.blogs.nytimes.com/2015/03/04/one-twin-exercises-... They took identical twins who had already grown to adulthood together and analyzed differences between the sibling who exercised a lot and the one who didn't. Guess what: they found differences that a genetic analysis would not predict! It's trivial in my mind that two identical twins who grew up in very different environments would look noticeably different due to developmental differences. I don't even know what you're arguing over, I never said faces are not genetically determined, only that other things also affect it. That would be the reason for that "almost" part of your assertion. I'm saying that difference is not negligible, some people look very similar by chance. A quick search led me to this: http://www.npr.org/blogs/pictureshow/2011/12/26/144282436/the-photographic-fascination-with-twins http://www.npr.org/blogs/pictureshow/2011/12/26/144282436/th... Close, but not identical.