The most common and most likely answer to this crossword clue is the 3 plus 2 plus 6 letter word OUT OF AFRICA
I've seen this crossword clue in The Guardian
O
U
T
O
F
A
F
R
I
C
A
More clues leading to the result OUT OF AFRICA
Buddy explains!
The straight part
We know that "one of 26 22 down’s" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one of 26 22 down’s = out of africa.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.