Blood Culture Method for the Study of Bovine Chromosomes

Abstract

THE development of leucocyte culture techniques^1–3 has greatly facilitated the investigation of chromosome anomalies associated with various human disorders^4–9. Chromosome investigations on domestic animals with similar disorders have been relatively rare, probably because the techniques used for the delineation of human chromosomes are often inapplicable. The most popular procedure for the cultivation of leucocytes involves the use of navy bean extracts both as a hæmagglutinating agent^1,3 and as a mitogenic agent^10,11. Reports from various laboratories have indicated that phytohæmagglutinin M used for the separation of human leucocytes is ineffective on the erythrocytes of several domestic and wild animals^12–14. The dextran method developed by Nichols and Levan for the separation of leucocytes from laboratory animals¹⁵ has been extended successfully to some domestic and wild animals when the phytohæmagglutinin method has failed to provide adequate amounts of leucocytes for culture¹². Neither the phytohæmagglutinin method nor the dextran method has been efficient enough for the separation of bovine leucocytes; consequently, investigators concerned with the investigation of bovine chromosomes have resorted to various agents such as fibrinogen¹⁶ and ficoll¹³ or to prolonged centrifugation^14,17 for obtaining leucocytes. In the course of our work on the chromosomes of cattle with lymphosarcoma we have developed a simple method which provides good preparations of bovine chromosomes. The method has also proved efficient for the investigation of somatic chromosomes of other domestic animals.