Origin of single pronucleated human zygotes

Area of Science:

• Embryology
• Reproductive Biology
• Genetics

Background:

• Diploidy in early embryos can arise from either fertilization or artificial activation.
• Distinguishing the source of diploidy is crucial for understanding reproductive processes and improving assisted reproductive technologies.

Purpose of the Study:

• To differentiate between fertilization and parthenogenetic activation as causes of diploidy in human embryos.
• To determine the origin of diploidy in embryos developing from single pronucleated zygotes.

Main Methods:

• Analysis of 21 dividing embryos derived from single pronucleated zygotes.
• Sexing embryos using polymerase chain reaction (PCR) and fluorescence in situ hybridization (FISH).
• Presence of a Y chromosome was used as definitive evidence of fertilization.

Main Results:

• The Y chromosome was detected in 43% (9/21) of the analyzed embryos.
• This indicates that a significant proportion of these embryos originated from a fertilized egg.

Conclusions:

• The findings suggest that over 80% of embryos with diploidy from single pronucleated zygotes are likely a result of fertilization.
• Sex determination is a reliable method to distinguish between fertilization and artificial activation in embryo development.