Choice of routes east round perimeter of Sahara Desert (7)

I believe the answer is:

forsake

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'desert' is the definition.
(synonyms)

I cannot understand how the remainder of the clue works.

(Other definitions for forsake that I've seen before include "Leave in the lurch" , "'Abandon, desert (7)'" , "Give up" , "Abondon or renounce" .)

I've seen this clue in The Guardian.

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