I always love bio stuff and this is a fantastic post! I think on the ‘why sex?’ question, it’s not selfish gene enough.
Genes, not organisms or species, are the replicators, the predominant unit of selection. If you’re a replicator (gene) in a community of specialised cooperating[1] replicators (genome) sharing a vehicle (organism), horizontal transfer mechanisms (generalisation of sexual transfer) look like neighbour-replicators whose specialised job is to facilitate orderly migration of potential new neighbour-replicators. Of course you want (some nonzero quantity, usually, of) this[2]! (Especially to adapt to changing environments, including evolution of conspecifics.) Every lineage of life exhibits some horizontal transfer, whether sexual or not.
Virus and other intracellular parasitic replicators look like roving invader/pillagers from this perspective, breaking the orderly guarantees provided by horizontal transfer
I always love bio stuff and this is a fantastic post! I think on the ‘why sex?’ question, it’s not selfish gene enough.
Genes, not organisms or species, are the replicators, the predominant unit of selection. If you’re a replicator (gene) in a community of specialised cooperating[1] replicators (genome) sharing a vehicle (organism), horizontal transfer mechanisms (generalisation of sexual transfer) look like neighbour-replicators whose specialised job is to facilitate orderly migration of potential new neighbour-replicators. Of course you want (some nonzero quantity, usually, of) this[2]! (Especially to adapt to changing environments, including evolution of conspecifics.) Every lineage of life exhibits some horizontal transfer, whether sexual or not.
The real questions are then ‘why sex-in-particular?’ and ‘why sex-exclusively?‘, which this post touches on to some extent quite well. For interested readers, MacKay’s Information Theory, Inference, and Learning Algorithms has a great chapter ‘Why Have Sex?’, as another Oliver already pointed out.
Usually cooperating! Well, at least sort of sometimes cooperating?!
Virus and other intracellular parasitic replicators look like roving invader/pillagers from this perspective, breaking the orderly guarantees provided by horizontal transfer