Experimental demonstration that mammalian oocytes are not selective towards X- or Y-bearing sperm

Maurizio Zuccotti, Vittorio Sebastiano, Silvia Garagna, Carlo Alberto Redi

Research output: Contribution to journalArticle


Mammalian oocytes are thought to be neutral as for X- or Y-bearing sperm selection is concerned, and penetration of an oocyte by an X- or a Y-bearing sperm is considered a random event. This assumption is mainly based on a posteriori evidences of a nearly equal sex ratio at birth, but it has never been experimentally demonstrated. We have designed a simple experiment, which allowed the penetration of an oocyte by more than one sperm and the further sexing by PCR of each single pronucleus present within the ooplasm. For the first time, we provide experimental evidence that mammalian oocytes do not play a selecting role since a single oocyte may be simultaneously fertilised by both X- and Y-bearing sperm.

Original languageEnglish
Pages (from-to)245-246
Number of pages2
JournalMolecular Reproduction and Development
Issue number2
Publication statusPublished - Jun 2005


ASJC Scopus subject areas

  • Genetics
  • Developmental Biology
  • Cell Biology

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