Leave them in the lurch with refusal to give genetic material to graduate, on reflection (7)
I believe the answer is:
abandon
'leave' is the definition.
(to abandon is to leave or desert)
'refusal to give genetic material to graduate on reflection' is the wordplay.
'refusal' becomes 'no' (saying no to something).
'to give' means one lot of letters go next to another.
'genetic material' becomes 'DNA' (deoxyribonucleic acid).
'to graduate' becomes 'BA' (someone with a Bachelor of Arts degree).
'on reflection' says the letters should be written backwards.
'no'+'dna'+'ba'='nodnaba'
'nodnaba' backwards is 'ABANDON'.
'them in the lurch with' acts as a link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for abandon that I've seen before include "Leave, desert" , "Desert or yield without restraint" , "Permanently desert" , "Desert - it's wild" , "Forsake, leave behind" .)