Genetic variability in the Skyros pony and its relationship with other Greek and foreign horse breeds

In Greece, seven native horse breeds have been identified so far. Among these, the Skyros pony is outstanding through having a distinct phenotype. In the present study, the aim was to assess genetic diversity in this breed, by using different types of genetic loci and available genealogical information. Its relationships with the other Greek, as well as foreign, domestic breeds were also investigated. Through microsatellite and pedigree analysis it appeared that the Skyros presented a similar level of genetic diversity to the other European breeds. Nevertheless, comparisons between DNA-based and pedigree-based results revealed that a loss of genetic diversity had probably already occurred before the beginning of breed registration. Tests indicated the possible existence of a recent bottleneck in two of the three main herds of Skyros pony. Nonetheless, relatively high levels of heterozygosity and Polymorphism Information Content indicated sufficient residual genetic variability, probably useful in planning future strategies for breed conservation. Three other Greek breeds were also analyzed. A comparison of these with domestic breeds elsewhere, revealed the closest relationships to be with the Middle Eastern types, whereas the Skyros itself remained isolated, without any close relationship, whatsoever

PCR-RFLP analysis of mitochondrial DNA cytochrome b gene among Greek horse breeds

PCR was used to investigate the genetic differentiation and phylogenetic relationships among five Greek horse breeds at the mitochondrial DNA level. Specifically, a 1350-bp segment comprising the entire cytochrome b gene of mitochondrial DNA was amplified and subsequently screened for RFLPs. Six out of ten restriction endonucleases were found to detect variability, and nine different haplotypes were observed, all belonging to the same phylogenetic assemblage. Haplotype-1 was the most common and possessed the highest frequency in all five breeds. The average values of the observed interpopulation and intrapopulation diversity among breeds were similar (mean = 0.30% and 0.27%, respectively). The results obtained contrast with the theory of a separate origin for Greek horse breeds and indicate an extensive admixture among them. This is also the case with the Skyros pony. Finally, the genetic relationships among breeds suggested by mtDNA data were in accordance with RAPD data

Induction of human tissue plasminogen activator in the mammary gland of transgenic goats

Three transgenic females from a first generation transgenic male were induced to lactate between 11 and 12 months of age using a series of estrogen and progesterone injections. The milk contained human longer acting tissue plasminogen activator (LAtPA) at comparable concentrations (1-3 mg/ml) as occurred in the original founder female. In addition, the transgenic male was induced with a hormonal regime and was shown to produce 0.85 mg/ml of LAtPA. Milk protein gels indicated that the milk products (casein, IgG) were essentially normal. These experiments show that expression data for this vector can be evaluated in a shorter period of time in dairy goats than would be required through normal gestation and lactation schedules and can be used to identify the relative expression of transgenes in mammary tissue that would occur during normal lactation