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		Procedure for UV irradiation 1) We put 15 embryos, randomly oriented in their chorion in 3 different petri dishes. To produce the UV irradiation we used a 254 nm CL-1000 UV crosslinker. To change the UV doses we can change the exposure times. Nevertheless, in this experimentwe increased the irradiation without change the time of exposure. 2.) Exposure I ( 1.8 mJ/cm2) We placed 15 embryos in a petri dish and then we put the petri dishes in the CL-1000 UV crosslinker as explained previously. 3)Exposure II ( 3.6 mJ/cm2) Same thing but the level of irradiation was doubled. 4)We also put 15 embryos in a petri dish and did not irradiated them. Theyserved as reference during the observation (the next day). 5)We placed the 3 petri dishes to incubate at 28ºC in embryo media.