This = mRNA copy ?

Context:

Once they had created iPSCs, Rossi and his team showed they could use a similar technique to turn them into muscle cells. Normally, this is done by exposing them to a cocktail of growth factors and nutrients, but Rossi and his colleagues instead made an mRNA copy of MYOD, a gene that turns stem cells into muscle cells, and infused this into the iPSCs. Within days, the stem cells had turned into muscle cells.