“Walking to the subway, Aomame kept thinking about the strangeness of the world. If, as the dowager had said, we were nothing but gene carriers, why do so many of us have to lead such strangely shaped lives? Wouldn’t our genetic purpose – to transmit DNA – be served just as well if we lived simple lives, not bothering our heads with a lot of extraneous thoughts, devoted entirely to preserving life and procreating? Did it benefit the genes in any way for us to lead such intricately warped, even bizarre, lives?… how could it possibly profit the genes to have such people existing in this world? Did the genes merely enjoy such deformed episodes as colorful entertainment, or were these episodes utilized by them for some greater purpose?”

“If, as the dowager had said, we are nothing but gene carriers, why do so many of us have to lead such strangely shaped lives? Wouldn’t our genetic purpose—to transmit DNA—be served just as well if we lived simple lives, not bothering our heads with a lot of extraneous thoughts, devoted entirely to preserving life and procreating? Did it benefit the genes in any way for us to lead such intricately warped, even bizarre, lives?”

“Different sorts of survival machine appear very varied on the outside and in their internal organs. An octopus is nothing like a mouse, and both are quite different from an oak tree. Yet in their fundamental chemistry they are rather uniform, and, in particular, the replicators that they bear, the genes, are basically the same kind of molecule in all of us—from bacteria to elephants. We are all survival machines for the same kind of replicator—molecules called DNA— but there are many different ways of making a living in the world, and the replicators have built a vast range of machines to exploit them. A monkey is a machine that preserves genes up trees, a fish is a machine that preserves genes in the water; there is even a small worm that preserves genes in German beer mats. DNA works in mysterious ways.”

“We are all a complete mixture;yet at the same time,we are all related.Each gene can trace its own journey to a different common ancestor.This is a quite extraordinary legacy that we all have inherited from the people who lived before us.Our genes did not just appear when we were born.They have been carried to us by millions of individual lives over thousands of generations.”

“Individuals are not stable things, they are fleeting. Chromosomes too are shuffled into oblivion, like hands of cards soon after they are dealt. But the cards themselves survive the shuffling. The cards are the genes. The genes are not destroyed by crossing-over, they merely change partners and march on. Of course they march on. That is their business. They are the replicators and we are their survival machines. When we have served our purpose we are cast aside. But genes are denizens of geological time: genes are forever.”

“The point to remember is that the issue is not nature versus nurture. It is the balance between nature and nurture. Genes do not make a man gay, or violent, or fat, or a leader. Genes merely make proteins. The chemical effect of these proteins may make the man's brain and body more receptive to certain environmental influences. But the extent of those influences will have as much to do with the outcome as the genes themselves. Furthermore, we humans are not prisoners of our genes or our environment. We have free will. Genes are overruled every time an angry man restrains his temper, a fat man diets, and an alocholic refuses to take a drink. On the other hand, the environment is overruled every time a genetic effect wins out, as when Lou Gehrig's athletic ability was overruled by his ALS. Genes and the environment work together to shape our brains, and we can manage them both if we want to. It may be harder for people with certain genes or surroundings, but "harder" is a long way from pedetermination.”