The best replacement for gametes is spores.

The best alternatives to gametes are rated as following:
★★★★★  spores
★★★★★  somatic cells
★★★  zygotes
★★  somatic
★★  alleles
★  zygote
★  male gametes
★  gonads
★  cells
  germ cells
  meiosis
  reproductive cells
  body cells
  gametophytes

Your alternative for gametes is not listed? Suggest!
Speaking about gametes, one probably shouldn't forget about half the number of chromosomes.

Other search terms related to gametes and their ratings are:
★★★★★ half the number of chromosomes
You have in mind a companion for gametes and it is not yet here? Propose!



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