元もとを辿たどる

expression, godan verb (-ru)

trace back to the origin

Used when investigating the root cause, historical source, or original form of something.

• この言こと葉ばの語ご源げんを元もとを辿たどると、ラテン語ごに行いき着つく。

  If you trace the origin of this word back, you arrive at Latin.

• 問もん題だいの原げん因いんを元もとを辿たどって調しらべる必ひつ要ようがある。

  We need to investigate by tracing back to the root cause of the problem.