One of the conditions for Hardy-Weinberg equilibrium is no gene flow. This means there is no movement of alleles into or out of the population.

Here's why this is important:

* Gene flow can introduce new alleles or change the frequencies of existing alleles. This disrupts the equilibrium, causing the allele frequencies to shift away from the predicted Hardy-Weinberg proportions.

For example, if individuals from a population with a high frequency of a certain allele migrate into a population with a low frequency of that allele, the allele frequency in the receiving population will increase.

Let me know if you'd like to know about other conditions for Hardy-Weinberg equilibrium!