He found that a gene called "complement component 4", it's called "C4" for short, comes in dozens of different forms in different people's genomes, and these different forms make different amounts of C4 protein in our brains.
Vio que un gen llamado "componente 4 del complemento", o C4 en su forma abreviada, se manifiesta de varias maneras distintas en el genoma de diferentes personas, y estas maneras distintas fabrican distintas cantidades de proteínas C4 en el cerebro.