2.2. Colorado experiment
2.2.1. Reagents
Reagents were purchased from Sigma-Aldrich (St. Louis,
MO, USA) unless otherwise specified. The oocyte maturation
medium was a medium based on Tissue Culture Medium199
(TCM-199) with Earle’s salts and modified to contain
hormones and other additives as described elsewhere [10].
Media for IVF and embryo culture were the series Fertilization-
Chemically Defined Medium (F-CDM) (fertilization),
CDM-1 (early embryo culture), and CDM-2 (later stage culture)
[10]. F-CDMmediumwas supplementedwith10mg/mL
heparin, 25 mg/mL gentamycin sulfate, and 20 mg/mL amikacin
for bothX-sorted and nonsorted sperm. TomaintainpH
in air during brief embryo handling for vortexing and
checking cleavage, lowbicarbonate (5mM) versions of CDM-
1 and -2 media were used [10]. The CDM-2 culture medium
contained 0.25 mM phenazine ethosulfate to decrease lipid
content of embryos [10]. Syngro medium, straws, plugs, and
six-well manipulation plates were obtained from Bioniche
(Pullman,WA, USA).