Sex determination in cattle based on simultaneous amplification of a new male-specific DNA sequence and an autosomal locus using the same primers.

A PCR-based method for sex determination of bovine DNA samples and embryo biopsies is presented. Using only one primer pair both the male-specific sequence FBNY (127 bp) and a sex-independent control PCR-fragment, the microsatellite marker FBN17 (136-140 bp) are generated in the same PCR reaction. Synteny mapping assigned the male-specific sequence to bovine chromosome Y (BTA Y), whereas FBN17 was mapped to bovine chromosome 2.

Quantification of Y chromosome bearing spermatozoa of cattle using in situ hybridization.

An easy assay for quantification of Y chromosome-bearing sperm (Y-sperm) is needed, especially to monitor sperm separation techniques. In the present study a tritiated bovine male-specific DNA fragment was tested for identification of Y-sperm by in situ hybridization. A protocol for in situ hybridization to bovine sperm was developed and used to study the proportion of Y-sperm of 12 bulls.

Gene transfer experiments in cattle.

Various methods for gene transfer in cattle are described. Four vectors containing (1) the bovine papilloma virus DNA, (2) the alcohol dehydrogenase gene of Drosophila melanogaster, and the human (3) and the bovine (4) growth hormone gene were used for gene injection in bovine zygotes. The period between 78 and 82 h after prostaglandin treatment was determined as the optimum time for collection of bovine zygotes.

[Fat metabolism in growth-selected laboratory mice].

The object of the present study was to characterize the selection-conditioned differentiation of the biological performance of laboratory mice having been selected for 13 generations at the age of 6 weeks to body mass (Du-6) as well as simultaneously to body mass and high physical capacity (Du-6 + LB) by parameters of fat metabolism. The improved physical capacity with unchanged body composition (Du-6 + LB) coincides with increasing activity of dehydrogenases supplying NADPH (glucose-6-phosphate-dehydrogenase, 6-phosphate-gluconate-dehydrogenase, NADP-malate-dehydrogenase, NADP-isocitrate-dehydrogenase) in the liver. The doubling of the fat content of the body (Du-6) was accompanied by a significant increase of the G-6-PDH- and fatty-acid synthetase activity in the fatty tissue.

Selection for different growth parameters in laboratory mice and its correlated effects on body composition and organ weights.

Body composition and organ weights were determined in male mice sampled from 4 different lines of a selection experiment: DU-6P (selected for high protein amount), DU-6 (selected for high body weight), DU-6 + LB (selected for an index combining body weight and endurance fitness) and DU-K (unselected control line). Selection was carried out under the conditions of ad libitum feeding and standardization of litter size at birth. In all 3 selection lines a significant direct selection response was shown.