Embryos were removed from the RNAlater solution in minimal volume using a finely drawn mouth pipette, washed in PBS + 4% Tween20 (Sigma Chemical Co.), and placed into 10 μL of RNAGEM solution (ZyGEM NZ Ltd., Hamilton, New Zealand) for complete cell lysis, incubated at 75°C for 5 min, then immediately placed on ice. The DNA was removed with DNase I treatment at 37°C for 5 min, with inactivation of enzyme at 75°C for 5 min, followed by placing the sample on ice. Total RNA was then converted to cDNA using 20% vol/vol Superscript VILO MasterMix (Invitrogen, Thermo Fisher Scientific, Waltham, MA) according to the manufacturer’s instructions (mix and incubate at 25°C for 10 min, incubate at 42°C for 120 min for increased yields of cDNA, and terminate the reaction at 85°C for 5 min).