title: Origin of single pronucleated human zygotes.
abstract: OBJECTIVE
  Diploidy in embryos developing from single pronucleated zygotes can occur following parthenogenetic activation or by asynchronous inflation of pronuclei following fertilization. To distinguish between these two mechanisms, sexing was performed.
  
  
  RESULTS
  The presence of a Y chromosome in the embryo was considered proof that fertilization had occurred. Twenty-one dividing embryos originating from single pronucleated zygotes were analyzed using the polymerase chain reaction or fluorescence in situ hybridization. In total, 43% (9/21) of the embryos showed Y chromosomes.
  
  
  CONCLUSIONS
  It can be extrapolated that more than 80% of them originated from fertilized eggs.
authors.affiliation: Cornell University Medical College, New York, New York 10021.
authors.forename: S
authors.initials: S
authors.lastname: Munné
authors.forename: Y X
authors.initials: YX
authors.lastname: Tang
authors.forename: J
authors.initials: J
authors.lastname: Grifo
authors.forename: J
authors.initials: J
authors.lastname: Cohen
mesh_terms: D002467:Cell Nucleus / Q000502:physiology*; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D016133:Polymerase Chain Reaction; D012732:Sex Determination Analysis; D014960:X Chromosome; D014998:Y Chromosome; D015053:Zygote / Q000502:physiology*