Explanation

Option A is not correct (and the right answer): According to the Official UPSC Answer Key, statement A is incorrect because fully functional, viable, self-replicating intact artificial chromosomes cannot simply be constructed by arbitrarily joining random chromosomal segments taken from entirely different species without cellular chromosomal incompatibilities and breakdown.

– Option B is correct: Artificial, chemically synthesized functional DNA sequences (oligonucleotides and synthetic genes) are routinely synthesized in laboratory facilities.
– Option C is correct: Extracted DNA is replicated outside living cells via Polymerase Chain Reaction (PCR) in vitro.
– Option D is correct: Plant and animal cells are cultured and undergo mitosis in laboratory petri dishes and bioreactors (plant tissue culture and cell line culture).

Hence, the incorrect statement is Option A.