This document discusses Markov chains and their applications, including to genetics. It provides definitions and notations for stochastic processes and Markov chains. It then gives examples of using Markov chains to model genetics, including Mendelian inheritance where the probabilities of different genetic combinations in offspring can be represented through a transition matrix. The document concludes that Markov chains can be used to model the mixing of dominant and recessive genes across generations and calculate genetic probabilities from a mathematical perspective.