A process of producing a transgenic multi-cellular plant or animal organism expressing a trait of interest and having a controlled distribution of said trait to progeny, wherein said process comprises hybridising a first multi-cellular organism or a cell thereof having a first heterologous DNA sequence comprising a first fragment of a nucleotide sequence encoding said trait of interest and a second multi-cellular organism or a cell thereof having a second heterologous DNA sequence comprising a second fragment of the nucleotide sequence encoding said trait of interest, whereby said first and said second heterologous sequences are designed such that said trait of interest arises due to RNA trans-splicing after said hybridation.