There are less than 7 billion people in the world today. We each have around 25,000 genes ( our genome ) which is all our hereditary information. It's encoded in DNA as the genotype. This is the blueprint or set of instructions for our characteristics. Our phenotype is our physical appearance, or how the genotype is "expressed ".Originally Posted by im_a_filipina
The environment - where we live, what we do - affects our phenotype, and also our personality, to make us all different.
Our DNA profile is unique, although " identical " twins ( resulting from a single fertilized egg ) do have virtually identical DNA ( genotype ). However, their phenotype is not identical and differences in appearance become more marked as they grow older.
Fingerprints ARE unique - even in " identical " twins, from birth, because of different environment in the womb ( uterus ).
Similarly, increasing use is made of facial recognition technology which is now installed in the gates of every major UK airport. People with " biometric " passports have a chip containing information about the holder's face ( part of their phenotype ). These are taken from their photo, such as distance between eyes, nose, mouth and ears. The details are checked against UK Border Agency systems.
" Personalised " medicine is the hope for the future. Knowing our unique genome could allow drugs targeted for the particular genes involved in any disease ( such as cancer ) which we might have, or be at risk of developing in the future. On the other hand, " designer babies " raises all sorts of ethical questions. But there's no doubt each of us IS unique - even if our genotypes are surprisingly similar to mice and other species !
