When linked to a noun,
を元（もと）に is an expression that indicates that something is ‘based on (A)’, ‘from (A)’, or ‘according to (A)’. This is a combination of
を, the noun 元（もと） ‘origin’, and
に. The literal meaning is similar to ‘with (A) as the origin, (B)’, and is used primarily to reference a source from which something is created or started.
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このドラマは実際（じっさい）に起（お）こったことをもとに作（つく）られたそうだ。
Apparently, this TV show was created based on actual events.
研究（けんきゅう）の結果（けっか）をもとにレポートを書（か）いてください。
Please write a report based on the results of the research.
私（わたし）はこのデータをもとにこのグラフを作成（さくせい）しました。
I created this graph based on this data.
Most of the time, をもとに will be written without kanji, but it is also possible to see it as
を元（もと）に.
As this grammar pattern is mainly used to highlight an origin of creation, it will often be seen in sentences that use verbs like 書（か）く ‘to write’, できる ‘to be able’, and 作（つく）る ‘to make’.
Caution -
を元（もと）に ‘based on’ differs to
に基（もと）づいて ‘based on’, in that
に基（もと）づいて indicates a foundation from which the judgement or conclusion of (B) is made, while
を元（もと）に focuses more on being a source of inspiration for (B), or enabling (B).
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彼（かれ）は法律（ほうりつ）に基（もと）づいて処分（しょぶん）されるだろう。
He will be receiving punishment according to the law.
彼（かれ）は法律（ほうりつ）をもとに処分（しょぶん）されるだろう。
He will be punished based on the law.