Dictionary:

prepotent

  (prē-pōt'nt)

1. Greater in power, influence, or force than another or others; predominant.
2. Genetics. Of, having, or exhibiting prepotency.

[Middle English, from Latin praepotēns, praepotent-, present participle of praeposse, to be more powerful : prae-, pre- + posse, to be able or powerful.]

adjective

Having preeminent significance: ascendant, dominant, predominant, prevailing, regnant, ruling, supreme. See important/unimportant.

Having great power; of the two parents, the one with greater power to transmit heritable characteristics to the offspring.