  The observed single-handedness of biological amino acids and sugars has long
been attributed to autocatalysis. However, the stability of homochiral states
in deterministic autocatalytic systems relies on cross inhibition of the two
chiral states, an unlikely scenario for early life self-replicators. Here, we
present a theory for a stochastic individual-level model of autocatalysis due
to early life self-replicators. Without chiral inhibition, the racemic state is
the global attractor of the deterministic dynamics, but intrinsic
multiplicative noise stabilizes the homochiral states, in both well-mixed and
spatially-extended systems. We conclude that autocatalysis is a viable
mechanism for homochirality, without imposing additional nonlinearities such as
chiral inhibition.
