L. Di Stasio

PCR–RFLP analysis of mitochondrial DNA in tench Tinca tinca

Polymorphism was detected at ND1, ND6, D-loop and cyt b segments of mtDNA in 105 tench (Tinca tinca L.), using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique and five composite haplotypes were identified. The diversity indices and the results of the population comparisons revealed that the identified markers provide a powerful tool for further studies on this species.

Analysis of genetic variation in Agerolese cattle breed

The Agerolese is a local Italian cattle breed reared in the province of Naples, in the proximity of the town of Agerola. It is a dual-purpose breed, which originated during the nineteenth century from an autochthonous nucleus of Podolian cows crossed with Swiss Brown, Dutch Friesian, and Jersey bulls. After 1940, the breed was severely threatened by the substitution with purebred Italian Brown and Holstein Friesian cattle (Felius, 1995). In 2002 it numbered only 13 males in natural service and 100 breeding females (EAAP, http://www. tiho-hannover.de/einricht/zucht/eaap/). Therefore, according to the FAO criteria for breed categorization, based on the number of breeding subjects as well as on the trend in population size (http://dad.fao.org), the status of the Agerolese should be classified as critical. Moreover, its effective genetic size, Ne, is approximately 46, slightly below the critical value of 50 that corresponds to a rate of inbreeding of 1% per generation, which is commonly accepted as the maximum tolerable level. The reasons for conservation of the breed rely on its integration into agricultural production systems of low to medium input. Agerolese is well adapted to mountainous country and can be fed on products of pruning and undergrowth. The milk is used to produce the Provolone del Monaco, a cheese of remote origins protected by the Slow Food Foundation for Biodiversity. Recently, a specification has been developed to apply for the Protected Designation of Origin (Peretti, personal

Variability of Leptin gene promoter in cattle

Abstract A preliminary analysis on the variability of Leptin gene promoter in seven cattle breeds was carried out, focusing the attention on the SNP at nt 1759, which has been suggested to affect some quantitative traits in cattle. In addition, the linkage disequilibrium with the C305T mutation in exon 2 of Leptin gene was tested. The results indicate that the Leptin gene promoter is polymorphic in all the analysed breeds, with significant betweenbreed differences. Pairwise comparison of genotypes at the two considered SNPs revealed a significant linkage disequilibrium, with the presence of the haplotypes 1759C - 305T and 1759G - 305C.

Transcript analysis at DGAT1 reveals different mRNA profiles in river buffaloes with extreme phenotypes for milk fat

Buffalo DGAT1 (diacylglycerol O-acyltransferase 1) was mainly investigated for the characterization of the gene itself and for the identification of the K232A polymorphism, similar to what has been accomplished in cattle, although no information has been reported so far at the mRNA level. The importance of DGAT1 for lipid metabolism led us to investigate the transcript profiles of lactating buffaloes characterized as high (9.13 ± 0.23) and low (7.94 ± 0.29) for milk fat percentage, and to explore the genetic diversity at the RNA and DNA level. A total of 336 positive clones for the DGAT1 cDNA were analyzed by PCR and chosen for sequencing according to the differences in length. The clone assembling revealed a very complex mRNA pattern with a total of 21 transcripts differently represented in the 2 groups of animals. Apart from the correct transcript (17 exons long), the skipping of exon 12 is the most significant in terms of distribution of clones with 11.6% difference between the 2 groups, whereas a totally different mRNA profile was found in approximately 12% of clones. The sequencing of genomic DNA allowed the identification of 10 polymorphic sites at the intron level, which clarify, at least partially, the genetic events behind the production of complex mRNA. Genetic diversity was found also at the exon level. The single nucleotide polymorphism c.1053C>T represents the first example of polymorphism in a coding region for the DGAT1 in the Italian Mediterranean breed. To establish whether this polymorphism is present in other buffalo breeds, a quick method based on PCR-RFLP was set up for allelic discrimination in the Italian Mediterranean and the Romanian Murrah (200 animals in total). The alleles were equally represented in the overall population, whereas the analysis of the 2 breeds showed different frequencies, likely indicating diverse genetic structure of the 2 breeds. The T allele might be considered as the ancestral condition of the DGAT1 gene, being present in the great part of the sequenced species. These data add knowledge at the transcript and genetic levels for the buffalo DGAT1 and open the opportunity for further investigation of other genes involved in milk fat metabolism for the river buffalo, including the future possibility of selecting alleles with quantitative or qualitative favorable effects (or both).

Variability of some genes of the somatotropic axis in the Piemontese cattle breed

Growth hormone (GH) is a major participant in the control of several complex physiological processes, including growth and metabolism. The growth promoting aspects are generally mediated by the insulin-like growth factor 1 (IGF-1), produced primarily in the liver in response to GH, while the metabolic effects are mainly the result of the GH direct binding to its receptors (GHR) on target cells. The production of GH is modulated by growth hormone releasing hormone (GHRH) and somatostatin (SST); the former stimulates both the synthesis and the secretion of GH, the latter inhibits the GH release (Frohman and Jansson, 1986; Bonneau, 1991; Buyse and Decuypere, 1999; Duclos et al., 1999; Sodhi and Rajput, 2001). Due to the several effects of GH, the genes coding for GH and other hormones and factors involved in growth have been suggested.........