High resolution DNA flow cytometry of boar sperm cells in identification of boars carrying cytogenetic aberrations Jacob Larsen a,1 , Knud Christensen b , Jørgen K. Larsen a , Peter Østrup Jensen a,2 , Ingemar Gustavsson c , Ib Jarle Christensen a,* a Finsen Laboratory, Finsen Centre, Copenhagen University Hospital, Strandboulevarden 49, DK-2100 Copenhagen, Denmark b Department of Animal Science and Animal Health, Royal Veterinary and Agricultural University, Grønnegaardsvej 2, DK-1870 Frederiksberg, Denmark c Department of Breeding and Genetics, Swedish University of Agricultural Sciences, P.O. Box 7023, S-750 07 Uppsala, Sweden Received 10 July 2003; received in revised form 30 October 2003; accepted 1 November 2003 Abstract The cytogenetic quality of boars used for breeding determines the litter outcome and thus has large economical consequences. Traditionally, quality controls based on the examination of simple karyograms are time consuming and sometimes give uncertain results. As an alternative, the use of high-resolution DNA flow cytometry on DAPI-stained sperm cell nuclei (CV  1:3%) was investigated as a screening method for the cytogenetic quality of boars. By analyzing a series of 25 animals judged normal by their fertility statistics and a series of seven animals with known reciprocal translocations, a model for identifying sperm cells from cytogenetically aberrant animals was proposed. This model was applied to a series of 50 uncharacterized animals. The model successfully identified a mosaic or chimaeric carrier of an aberrant X chromosome. However, implementation of this technique for screening purposes would necessitate essential improvements in standardization and measurement precision. # 2003 Elsevier Inc. All rights reserved. Keywords: Flow cytometry; Cytogenetics; Sperm cells; DNA content; Translocations Theriogenology 62 (2004) 501–511 * Corresponding author. Tel.: þ45-3545-5727; fax: þ45-3538-5450. E-mail address: ib.jarle@finsenlab.dk (I.J. Christensen). 1 Present address: Department of Clinical Immunology, Diagnostic Centre, Copenhagen University Hospital, Blegdamsvej 9, DK-2100 Copenhagen, Denmark. 2 Present address: BioCentrum, Building 301, Technical University of Denmark, DK-2800Lyngby, Denmark. 0093-691X/$ – see front matter # 2003 Elsevier Inc. All rights reserved. doi:10.1016/j.theriogenology.2003.11.008