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Actually, chromosomes are a worse target for predicting behaviors in terms of sex-linked traits since genes during conception can and will be exchanged between

Actually, chromosomes are a worse target for predicting behaviors in terms of sex-linked traits since genes during conception can and will be exchanged between the X and Y chromosomes in humans. This is why sometimes the SRY gene is found in women (XX) despite clearly having an operative uterus and ovaries. Nature loves to pick on us humans when it comes to assuming fixed traits.

FD3SA 11y ago
How interesting. So using a statistically significant population sample, there will be no phenotypic differences between carriers of X versus Y chromosomes? If so, science has progressed quite far in the last few years that I've been away.
- norea-armozel 11y ago
  There won't be much difference beyond reproductive roles and other physical traits, but the brain doesn't seem to be affected all that much, no. Basically, there's no gene for being a programmer just as there's no gene for being a (good/bad) parent. Why would Nature bother to pre-compute/compile all possible states/outcomes? Better to compute/compile the essentials for a living species then let the rest be handled by history.
  - FD3SA 11y ago
    > There won't be much difference beyond reproductive roles and other physical traits, but the brain doesn't seem to be affected all that much, no. Ah so evolution stops at the neck! Genius! The more you know...
    - norea-armozel 11y ago
      Evolution stops specializing when said specialization offers no beneficial adaptation sufficient for the metabolic cost. It's why the vast majority of living organisms have much simpler brains, body plans, and even reproductive strategies. Humans and other similar animals are rare little things in the vast ocean of simpler, more elegant mutations.
belorn 11y ago
I picked chromosomes and genes mostly because they are at least involved in the creation of the human brain, which was a bit hastily written. I agree that it makes for a poor prediction to determine who is going to have a tendency for mood swings. Gender, to the degree that gender is not about culture, is quite far down the list of predictors, and even further down on the list would be hormones.
- leereeves 11y ago
  The literature I've read says hormones are "involved in the creation of the brain". "Steroid hormones are a dominant and pervasive source of sex differences by mediating developmental processes that are enduring and establish adult physiological and behavioural responses relevant to the reproductive constraints of each sex." From Multifaceted origins of sex differences in the brain, 1 February 2016, an open access article. http://rstb.royalsocietypublishing.org/content/371/1688/20150106.full#sec-7 http://rstb.royalsocietypublishing.org/content/371/1688/2015...
  - belorn 11y ago
    The same study says: "Animal models have also allowed us to move beyond hormones and to an appreciation of the important role of sex chromosomes. Study of these mice has revealed important roles for chromosome complement on body weight and feeding, aggression and habit formation, to name a few." And section 8: "Some argue it is pure folly to study neuroanatomical sex differences with the hope of understanding sex differences in behaviour as the connection between anatomy and behaviour is often weak or even non-existent [50]. Indeed, the most celebrated sex difference in the brain, the SDN, has not been clearly tied to any specific behavioural or physiological endpoint, although see above discussion regarding sexual orientation. While it is true that anatomical or physiological differences in the brain often do not map onto clear differences in behaviour, does this mean they are not important or even, not real? Many studies of sex differences in brain anatomy or neural functioning are perfectly sound, meaning they are fully powered and technically executed using well vetted and accepted approaches, yet a strong correlation between variance in anatomy and variance in behaviour is about the best one can hope for in establishing a causal relationship."

FD3SA 11y ago

How interesting. So using a statistically significant population sample, there will be no phenotypic differences between carriers of X versus Y chromosomes? If so, science has progressed quite far in the last few years that I've been away.

norea-armozel 11y ago
There won't be much difference beyond reproductive roles and other physical traits, but the brain doesn't seem to be affected all that much, no. Basically, there's no gene for being a programmer just as there's no gene for being a (good/bad) parent. Why would Nature bother to pre-compute/compile all possible states/outcomes? Better to compute/compile the essentials for a living species then let the rest be handled by history.
- FD3SA 11y ago
  > There won't be much difference beyond reproductive roles and other physical traits, but the brain doesn't seem to be affected all that much, no. Ah so evolution stops at the neck! Genius! The more you know...
  - norea-armozel 11y ago
    Evolution stops specializing when said specialization offers no beneficial adaptation sufficient for the metabolic cost. It's why the vast majority of living organisms have much simpler brains, body plans, and even reproductive strategies. Humans and other similar animals are rare little things in the vast ocean of simpler, more elegant mutations.

belorn 11y ago

I picked chromosomes and genes mostly because they are at least involved in the creation of the human brain, which was a bit hastily written. I agree that it makes for a poor prediction to determine who is going to have a tendency for mood swings. Gender, to the degree that gender is not about culture, is quite far down the list of predictors, and even further down on the list would be hormones.

leereeves 11y ago
The literature I've read says hormones are "involved in the creation of the brain". "Steroid hormones are a dominant and pervasive source of sex differences by mediating developmental processes that are enduring and establish adult physiological and behavioural responses relevant to the reproductive constraints of each sex." From Multifaceted origins of sex differences in the brain, 1 February 2016, an open access article. http://rstb.royalsocietypublishing.org/content/371/1688/20150106.full#sec-7 http://rstb.royalsocietypublishing.org/content/371/1688/2015...
- belorn 11y ago
  The same study says: "Animal models have also allowed us to move beyond hormones and to an appreciation of the important role of sex chromosomes. Study of these mice has revealed important roles for chromosome complement on body weight and feeding, aggression and habit formation, to name a few." And section 8: "Some argue it is pure folly to study neuroanatomical sex differences with the hope of understanding sex differences in behaviour as the connection between anatomy and behaviour is often weak or even non-existent [50]. Indeed, the most celebrated sex difference in the brain, the SDN, has not been clearly tied to any specific behavioural or physiological endpoint, although see above discussion regarding sexual orientation. While it is true that anatomical or physiological differences in the brain often do not map onto clear differences in behaviour, does this mean they are not important or even, not real? Many studies of sex differences in brain anatomy or neural functioning are perfectly sound, meaning they are fully powered and technically executed using well vetted and accepted approaches, yet a strong correlation between variance in anatomy and variance in behaviour is about the best one can hope for in establishing a causal relationship."