X chromosome inactivation studies in the Swiss Eringer breed

Investigations were carried out on cows of the Eringer breed because of the ir cowfighting behaviour. The observable interest in fighting between femal e animals is an integral element in the genetical diversity of the breed. I t is known that the phenotype of female Eringer animals is masculine and th at the fighting desire is also a characteristic feature of this breed when compared to other breeds. Cytogenetic examinations we carried out on Eringe r cattle. Short term cultures from lymphocytes and long term cultures from fibroblasts were made. The metaphases prepared from the cell cultures, were banded and the karyograms were compared to the international standard. Spe cial attention was given to the X chromosomes. In mammals the X chromosome is of special importance because of its variable genetic activity. Only one of the two X chromosomes is active in the somatic cells of females. The in activated X chromosome could be identified due to a different R-banding str ucture. The differences between the active and the inactive X chromosomes b etween different animals were astonishingly clear and no artefacts were vis ible. This would indicate a varying activity of both X chromosomes despite their partial activation and inactivation. A phenotypical and behaviour spe cific variation in this breed may be related to the different inactivation effects.