title: Difference in volume of X- and Y-chromosome-bearing bovine sperm heads matches difference in DNA content.
abstract: BACKGROUND
  To investigate the possibilities of sperm head volume as a sorting criterion for gender preselection, we determined the magnitude of the difference in volume of X- and Y-chromosome-bearing bull sperm heads.
  
  
  METHODS
  Bovine sperm heads were sorted on the basis of their DNA content in X- and Y-chromosome-bearing fractions, using an existing flow-cytometric technique. Images of sperm heads of both populations were recorded using Differential Interference Contrast (DIC) microscopy. After reconstructing the DIC images, the area and the optical thickness of sperm heads of both populations were determined.
  
  
  RESULTS
  We found a difference in volume of X- and Y-bearing bovine sperm heads matching the difference in DNA content (3.5-4%).
  
  
  CONCLUSIONS
  Our findings indicate that volume can be used as a criterion to distinguish X- and Y-chromosome-bearing sperm, making development of a technique to sort X- and Y-chromosome-bearing sperm based on head volume theoretically possible. A strong advantage of such a technique over the existing technique based on DNA content would be that X- and Y-chromosome-bearing sperm cells could thus be sorted without subjecting them to any staining.
authors.affiliation: Department of Cell Biology and Histology, Academic Medical Center, University of Amsterdam, The Netherlands. e.b.vanmunster@amc.uva.nl
authors.forename: E B
authors.initials: EB
authors.lastname: van Munster
authors.forename: J
authors.initials: J
authors.lastname: Stap
authors.forename: R A
authors.initials: RA
authors.lastname: Hoebe
authors.forename: G J
authors.initials: GJ
authors.lastname: te Meerman
authors.forename: J A
authors.initials: JA
authors.lastname: Aten
mesh_terms: D000818:Animals; D002417:Cattle; D004247:DNA / Q000032:analysis*; D005434:Flow Cytometry; D008297:Male; D008857:Microscopy, Interference; D013077:Sperm Head / Q000737:chemistry*; D014960:X Chromosome / Q000235:genetics*; D014998:Y Chromosome / Q000235:genetics*
chemical_list: D004247:DNA