Quote:
|
Originally Posted by 1010011010
Something can have a biological basis, yet have no genetic component. Fingerprints are not heritable, indeed identical twins will have different fingerprints, but no one chooses their pattern.
|
Fingerprints do have a genetic component, but your specific pattern is not coded for. (Which you probably meant).
On a more general note, there is a difference between something being heritable and heritability. A heritable trait is one influenced by genes. Heritability is a measure of the proportion of variation in a particular trait in a population due to genetic variation.
Something can have a strong genetic component and have a heritability of zero. Having a head clearly has a genetic component, but has a heritability of zero. The genes affected presence or absence of a head are fixed in the population, there is no genetic variation in the population for presence or absence of heads. So, heritability is zero. (Sorry, a bit of a tangent. I just like talking about heritability).
Quote:
|
Originally Posted by 1010011010
Sexual orientation could similarly be left to the chance vagarities of the prenatal environment. Set down from birth, a completely biological basis, but no strict heritability of the trait at all.
|
Certainly a possibility.