Guybrush

One point regarding free will versus genes is that a very primal part of our brain is the limbic system - the center of emotions and this is ancient. Inputs are processed and applied various emotional tags by it. It's not part of your free thinking. Let's say genes make you angry .. That's your genes talking. However, you have free will and you can suppress that anger. In that respect, you're not a slave to your genes.

However, generally speaking, we do follow them. Most of us by far tend to avoid unpleasant situations if we can and other things we don't like. Then we pursue good stuff - good food, sex, etc.

To understand the "biology morale theory" fully, you really need to understand evolution and even though people think they do, they usually don't because it's actually a rather expansive subject that incorporates a lot of theory most people don't even know about. Richard Dawkins is the nr.1 biologist to have popularized the idea of selfishness because he was able to convey to the man in the street the thoughts and learnings of his fellow evolutionary biologists. This morale theory has it's roots in a lot of this, but most philosophers don't understand it fully, I think, because of their lack of evolutionary understanding.

edit :

I can add some info for the curious. At the core of this idea is that every being is selfish and looking after itself. Itself means it's own genes - and we share our genes with our closest relatives, so you're gonna look out for them as well. So, we are all adapted through millions of years to effectively take care of our genes (survive and reproduce) and that has a lot of implications. It means that a lot of the things we do behaviourally are tailored to raise our fitness. Humans are social beings and by cooperating with others, your genes are more likely to survive and so selfishness becomes similar to altruism in some cases.

A lot of emotions are expected to be adaptations that have evolved because they raise our fitnesses. For example, most get jealous when their partner flirts with someone else. That makes perfect sense from a biological standpoint and most think flirting with someone else when you have a steady partner is morally wrong. The morale may not be hardcoded into us, but the emotions are and that's a likely morale view to arise from those.

People sometimes say "why do we feel sorry for kids in Africa then? Giving them money doesn't raise our fitness!" The answer is simple - we're social beings adapted to taking care of eachother and children has a special appeal to our warmer feelings. That is easily explained by evolutionary theory. If you then remember that evolution of our biology is relatively slow compared to the evolution of our culture, you'll realize that humans didn't evolve to live in big societies with TVs. Not long ago, in evolutionary time we lived in small communities where we all depended on eachother, more or less. If you see a starving kid on TV, your "genes" may not know that this kid is far, far away and has no impact on your fitness. You may react as if the kid was a part of your community and that helping it will benefit you.

Remember also that selfishness and preserving your genes is not a conscious agenda. It's hardcoded into all of us. You want sex, but you don't think "I wanna spread my genes!" In a similar way, I'm pretty sure starfish don't "know" why they do the things they do.

__________________
Something Completely Different