Serums are vials filled with a single gene. These serums can be injected into individuals using the Inoculator, but only into young life stages such as larvae, pollen or butterfly serums. To assign a gene to a serum open the Gene Database and click on one of the genes on the right hand side with an Empty Serum Vial to assign the gene. Before inoculation, the serum must be filled in the Polymeriser. A serum can hold up to 16 charges, one of which is used each time inoculation occurs.