Metahumans carried the metagene in their DNA, which at times could give them super powers, especially if such a metahuman were to be exposed to certain traumas. For example, Barry Allen was struck by lightning while simultaneously getting bathed with chemicals, and this gave him the ability to move at super speed. If he had been a normal human, he not only would have most likely died from electrocution, but even if he did survive, he wouldn't have developed any powers.
The origins of the metahuman race were as much of a mystery as the origins of the metagene itself. A person didn't have to have a metahuman parent in order to be born a metahuman, so presumably the metagene doesn't effect every generation. The Black Canary for example, is a metahuman, but her parents are normal homo sapiens.
- ↑ As seen in The Superman/Aquaman Hour of Adventure.
- ↑ The reason for this in the context of the fictional universe shown in DC Comics is because the White Martians did experiments on primitive humans with the metagene, who eventually would evolve into metahumans, but because of their tinkering with human DNA, only a handful of Metahumans existed in the future.