Roget's last edition, which forms the basis of culture (6)
I believe the answer is:
tissue
'forms the basis of culture' is the definition.
(a biologist may grow tissue cells through culture)
'roget's last edition' is the wordplay.
'last' says to take the final letters.
'edition' becomes 'issue' (I've seen this before).
The final letter of 'roget' is 't'.
't'+'issue'='TISSUE'
'which' is the link.
(Other definitions for tissue that I've seen before include "Soft thin paper in layers" , "Absorbent paper, used as handkerchief, say" , "Gauzy fabric" , "Skin or thin paper" , "load of lies?" .)