  We consider a recent innovative theory by Chastain et al. on the role of sex
in evolution [PNAS'14]. In short, the theory suggests that the evolutionary
process of gene recombination implements the celebrated multiplicative weights
updates algorithm (MWUA). They prove that the population dynamics induced by
sexual reproduction can be precisely modeled by genes that use MWUA as their
learning strategy in a particular coordination game. The result holds in the
environments of \emph{weak selection}, under the assumption that the population
frequencies remain a product distribution.
  We revisit the theory, eliminating both the requirement of weak selection and
any assumption on the distribution of the population. Removing the assumption
of product distributions is crucial, since as we show, this assumption is
inconsistent with the population dynamics. We show that the marginal allele
distributions induced by the population dynamics precisely match the marginals
induced by a multiplicative weights update algorithm in this general setting,
thereby affirming and substantially generalizing these earlier results.
  We further revise the implications for convergence and utility or fitness
guarantees in coordination games. In contrast to the claim of Chastain et
al.[PNAS'14], we conclude that the sexual evolutionary dynamics does not entail
any property of the population distribution, beyond those already implied by
convergence.
