In Plague Inc., winning the game often depends on how many DNA Points you can get, and how properly you spend them.
DNA Points come in two primary ways.. spreading your plague, and killing the population.
There are some tricks you can use to get more though, like when using genes. Four of the five DNA genes give you various DNA bonuses.
The DNA gene Metabolic Jump for example gives you more DNA when popping the red bio-hazard bubbles. This one is my personal favorite for most plagues, but it doesn’t work as well on the slower plague types like Fungus and Parasite. For those I prefer Cytochrome Surge, which gives you more DNA for popping orange DNA bubbles.
One nice trick that works well on Normal difficulty is to use the Mutation gene Darwinist with the Evolution gene Ionised Helix. This makes a good combo, because Darwinist increases the chance of your plague mutating symptoms, while Ionized Helix gives you bonus DNA when devolving. While this works nicely on Normal games, it doesn’t work on Brutal since Brutal decreases the DNA return you get after every refund.