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The difference between the length of female- and male-linkage map, which was created with a reference pedigree based on a commercial porcine population and using 163 microsatellite markers as well as 3 type-I markers (RYR1, PRKAG3, PIT1), was statistic analyzed. The results showed that the total length of female linkage map of autosomes is 2625.9 cm and the total length of the male linkage map is 2259.7 cm; the ratio between the total length of the female- and male-linkage maps is 1.16 : 1; except for the chromosomes 1 and 14, the female linkage maps of the other chromosomes are longer than the male linkage maps. The difference between the length of female- and male-linkage maps of chromosomes 1, 3, 5, 6, 7, 8, 10, 11, 12, 13, 14, 16, 17 and 18 is very significant (P<0.01) and the difference of chromosome 9 is significant (P<0.05); but there is no significance on chromosomes 2, 4, 12 and 15.

In order to rapidly amplify pig microsatellite markers and save materials,multiplex PCR was used and its reaction condition was optimized. Forty-six combinations of multiplex PCR with good effects were obtained. Thirty of them are duplex-PCRs, sixteen are triplex-PCRs. The results of multiplexes showed that the concentration of primers varied among 0.06 approximately 0.3 micromol/L, the Mg(2+) concentration among 1.5 approximately 3.0 mmol/L; 0.2 approximately 0.4 U of Taq polymerase and 1.0-, 1.2-, 1.4-, 1.6-fold buffer were used, the annealing temperature and the cycle number varied among 52 approximately 60 degrees and 32 approximately 50 degrees, respectively. All multiplexes were further combined into 17 sets for the electrophoresis on ABI 377 sequencer.

A commercial population created with 19 hybrid boars [Piétrain x (Piétrain x Hampshire)], 52 hybrid sows [Leicoma x (Large White x Landrace)] and their 332 offspring was used to construct a whole genome porcine linkage map. The genetic markers used in this study include 172 microsatellite markers and 3 type- I markers (RYR1, PIT1 and PRKAG3). All microsatellite markers were genotyped using multiplex PCR reactions and visualized on ABI 377 sequencer. Three type I markers were assayed using PCR-RFLP technique. CRIMAP (2.4) analysis revealed a total length of the sex-averaged map for SSC1-SSC18 by 2449.2 cM and the length of SSCX by 143.1 cM. The average interval distance accounts to 16.3 cM. The heterozygosity of the parents at the microsatellite loci averaged 0.70. This map will play an important role in screening of QTL for growth, carcass and meat quality and reproduction in commercial populations.

We estimated the genetic relationships between the endangered German Pustertaler-Sprinzen cattle breed and the Pinzgauer, Vosges and Simmental breeds--decided upon after consultation of the available historical literature. Within-breed diversity of the four breeds was also assessed. Twenty microsatellite markers were amplified in 27-50 unrelated individuals from populations of each breed. Within-breed variation was estimated from average heterozygosity values and mean number of alleles. Breed relationships were evaluated by genetic distance and a neighbour-joining tree was calculated from these estimates. Bootstrap resampling of loci tested the robustness of the tree topology obtained. A tree was also constructed from distance matrices using individual animals as operational taxonomic units. From both the average heterozygosity values and mean number of alleles calculated, the Pustertaler breed appears to be no more genetically impoverished than the other breeds analysed. The breed tree showed an 85% support for the Pustertaler-Pinzgauer grouping, and this result is echoed in the genetic distance values and allele-sharing individual tree.

A total of 1,130 bulls belonging to 20 half-sib families of German dairy cattle were genotyped for 229 microsatellite markers on 30 chromosomes. The data were used in an attempt to map quantitative trait loci applying regression as multiple-marker regression. For association analysis with a granddaughter design, the estimated breeding values for 3 milk traits were used: milk production, fat production and protein production. The empirical values of significance thresholds were determined by using a permutation test on the experimental data. Several significant QTLs were found on some chromosomes, especially on the chromosome 14. The results give a strong support for the experiments of Coppieters et al. and Ron et al.