人為 じんい突然 とつぜん変異 へんいではありませんでした
jin'itotsuzenhen'idewārimasendeshita

Noun
Desu Copula

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

1. Was not artificial mutation.; Was not human-induced mutation.

Past/Perfective
Negative
Polite
Formal Register