Genes are much easier to unlock than pathogens, however there is a limited amount of them. As you complete the game, new genes will be available. Play the game under the easy difficulty setting and complete it to unlock them quickly. You can also unlock additional genes after using the "Get Rare Genes" option by spending gems. Decrease the visibility of your disease by using genes for a more effective attack. This will slow the process for that disease to be cured. Stack two, three or even four visibility decreasing genes together.