ytEx209 contains [mel-46(+) + sur-5::GFP]. Maintain by picking GFP+. Culture at 20°C or higher in order not to lose the transgene. GFP minus worms are Mel or sterile at 25 C (completely penetrant). Strong but not fully penetrant Mel at 15 C. To start a yt5 homozygous culture transfer several GFP minus worms to 15°C.