The most common and most likely answer to this crossword clue is the 6 letter word MUTATE
I've seen this crossword clue in Financial Times
M
U
T
A
T
E
More clues leading to the result MUTATE
- Speechless about a temperature change
- Saying nothing about a temperature change
- Appear in new form? Art maybe taken up, then English
- Change Greek character with brief thank-you note
- Change in dog burying a bone, ultimately
- Transform mostly silent gallery
- Dog swallowing a tablet to enter altered state
- Change direction after hesitation over tasteless articles
- Morph‘s dog eating a bone at last
- Dog almost had to metamorphose
Buddy explains!

The straight part
We know that "metamorphose" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case metamorphose = mutate.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.
What does MUTATE mean?
MUTATE verb- To undergo mutation.
- To cause mutation.