co-segregation of marker plasmid and DNA of interest

Hi All

I have a basic question about transmission of extrachromosomal array after injection. So, I have been using the pRF4 plasmid together with PCR of my gene of interest to inject into wild type worms. As expected, I get both roller as well as non-roller worms. I read somewhere that the marker plasmid and DNA may not always cosegregate. Has anyone had any experience like this? I wanted to be sure that the transgenics I analyse are actually carrying my DNA of interest besides the rolle/marker plasmid.


Upon injection, the marker and gene of interest form extachromosomal arrays with (typically) hundreds of copies, so it’s unlikely that your gene will segregate away from the marker. However, it’s possible to observe the Rol phenotype but lose expression of your gene by at least two methods: mosaicism (the array is lost in tissues where your gene is expressed, but retained in the Rol tissues), and germline silencing (your gene is silenced, but rol-6 continues to express).