gamete vs roe

gamete

noun
  • A reproductive cell (sperm in males or eggs in females), having only half of a complete set of chromosomes. 

roe

noun
  • The sperm of certain fish. 

  • The eggs of fish. 

  • The ovaries of certain crustaceans. 

  • A mottled appearance of light and shade in wood, especially in mahogany. 

How often have the words gamete and roe occurred in a corpus of books? (source: Google Ngram Viewer )