人為 じんい突然 とつぜん変異 へんいじゃなかったです
jin'itotsuzenhen'ijanakattadesu

Noun
Desu Copula

The polite, past negative form of 人為突然変異

1. Wasn't artificial mutation.; Wasn't human-induced mutation.

Past/Perfective
Negative
Polite
Casual Register