title: Buoyancy and sedimentation of human X- and Y-bearing sperm.
abstract: The buoyant and sedimentation behaviors of human X- and Y-bearing sperm were examined in discontinuous density gradients of Nycodenz. The washed sperm placed at the bottom of the discontinuous density gradients of Nycodenz (23-50% in 3% steps) were centrifuged at 250 x g for various periods. The buoyant velocity of X-bearing sperm was faster than that of Y-bearing sperm. The sedimentation profiles of human sperm in the discontinuous density gradients of Nycodenz (4-20% in 2% steps) showed that X-bearing sperm sedimented faster than Y-bearing sperm. The separation of X- and Y-bearing sperm by means of centrifugation usually have been based on the assumption that smaller Y and larger X chromosomes might provide the difference in their apparent densities. The present results suggest that the separation cannot be due merely to a difference in their densities.
mesh_terms: D002469:Cell Separation; D002499:Centrifugation, Density Gradient; D006801:Humans; D007472:Iohexol; D008297:Male; D013094:Spermatozoa / Q000166:cytology* / Q000502:physiology; D014960:X Chromosome; D014998:Y Chromosome
chemical_list: D007472:Iohexol