Thus extensive genetic fingerprint reversal cheers in respect of complete school book (2,4,3,6,3,3,3,4)

'thus extensive genetic fingerprint reversal cheers in respect of complete school book' is the definition.
I can't judge whether this definition defines the answer.

'thus extensive genetic fingerprint reversal cheers in respect of complete school' is the wordplay.
I cannot quite understand how this works, but
'thus' could be 'so' (synonyms) and 'so' is found within the answer.
'extensive' could be 'long' (I've seen this in another clue) and 'long' is found in the answer.
'cheers' could be 'thanks' ('cheers' can informally mean 'thank you') and 'thanks' is present in the answer.
'of' could be 'o' and 'o' is present in the answer.
'complete' could be 'all' (similar in meaning) and 'all' is located in the answer.
'school' could be 'fish' (group of fishes) and 'fish' is present in the answer.
This explanation may well be incorrect...

Can you help me to learn more?