zygotichttp://www.oed.com/dictionary/zygotic_adj%3Ftab%3Dmeaning_and_usezygotic, adj.
First published 1921; not fully revised

zygoticadjective

Biology.
  1. 1909–
    Pertaining to or of the nature of a zygote, produced or characterized by zygosis.
    1. 1909
      The enumeration of the conceivable different varieties of gray rabbit, all alike in appearance but all different in breeding capacity, i.e., of different zygotic formula.
      W. E. Castle, Stud. Inheritance in Rabbits (Carnegie Inst. Publ. No. 114) 58
    2. 1977
      The second phase of embryology begins, controlled by zygotic genes.
      J. Cohen, Reproduction ix. 163

Originally published as part of the entry for zygote, n.

zygote, n. was first published in 1921; not fully revised.