  One possible explanation for magnetosensing in biology, such as avian
magnetoreception, is based on the spin dynamics of certain chemical reactions
that involve radical pairs. Radical pairs have been suggested to also play a
role in anesthesia, hyperactivity, neurogenesis, circadian clock rhythm,
microtubule assembly, etc. It thus seems critical to probe the credibility of
such models. One way to do so is through isotope effects with different nuclear
spins. Here we briefly review the papers involving spin-related isotope effects
in biology. We suggest studying isotope effects can be an interesting avenue
for quantum biology.
