Andrea Rando

Molecular characterization of the goat CSN1S1 01 allele

Caseins (α s1 , β, α s2 , e κ) represent about 80% of the whole protein content of ruminant milk. Each of these proteins is encoded by single copy genes ( CSN1S1 , CSN2 , CSN1S2 and CSN3 , respectively) clustered on a ∼200-kb segment of chromosome 6 (Ferretti et al. 1990; Gallagher et al. 1994) in the order: CSN1S1 , CSN2 , CSN1S2 and CSN3 (Mercier & Vilotte, 1993). Furthermore, in cattle and goat CSN1S1 and CSN2 are convergently transcribed (Leroux & Martin, 1996; Rijnkles et al. 1997) and are only 20 and 12 kb apart, respectively.

Triplication of α-globin genes is responsible for unusual α113Leu/α113His-globin chain ratios in sheep

By investigations at the DNA and protein level, it has been shown that in sheep a previously detected, presumed quantitative allele of theIIα113His gene, displaying a reduced efficiency (called theIIα113His↓ gene), is carried by a chromosome bearing three α-globin loci. In particular, five sheep having an α113Leu/α113His-chain ratio of about 13:1 (13:1 phenotype) possessed the —Iα113Leu—IIα113Leu—/—Iα113Leu—IIα113Leu —IIIα113His↓ genotype. One sheep showing a α113Leu/α113His-chain ratio of about 3:1 (3:1 phenotype) had the —Iα113Leu—IIα113His—/—Iα113Leu—IIα113Leu —IIIα113His↓ genotype, while one sheep having a chain ratio of about 6:1 (6:1 phenotype) carried the —Iα113Leu—IIα113Leu—IIα113His↓—/—Iα113Leu—IIα113Leu —IIIα113His↓ genotype. Nineteen sheep, displaying the common phenotypes, all possessed the αα/αα gene arrangement. Furthermore, the possible location of the gene with reduced efficiency and the expression of the three genes in the triple α-globin loci chromosome are discussed.

Sheep α-globin gene sequences: Implications for their concerted evolution and for the down-regulation of the 3′ genes

In sheep as in man and most other mammals, there are two α-globin genes (Iα and IIα), which are expressed at different levels, the upstream gene being the most efficient. In α-globin gene triplication and quadruplication, this trend is confirmed, i.e., the α-chain output of the downstream genes progressively decreases. In this study, we have determined the complete sequence of the cDNAs and of both the introns in a triple-α haplotype in which each gene could be recognized for the presence of distinct alleles. The sequence analysis reveals that the bodies of the three α-globin genes are essentially identical (99.9% homology) and moreover indicates that the down-regulation of additional α-globin genes in sheep is not the effect of sequence variation from the Cap to the Poly(A) addition sites. This striking similarity among α-genes is higher than that seen in other mammals and is probably sustained by particularly efficient mechanisms of gene conversion and cross-over fixation.

Identification and Characterization of the Donkey CSN1S2 I and II cDNAs

The αs2 casein, encoded by the CSN1S2 gene, is one of the three Calcium sensitive caseins present in the milk of ruminants of zootechnical interest and in the milk of Equidae species (horse and donkey). In the present study, we cloned, sequenced and analysed two different donkey CSN1S2 cDNAs that we called CSN1S2 I and CSN1S2 II. The first, which spans over a fragment of 1016 nt, is constituted by 19 exons and encodes for a predicted protein (called αs2-I) of 221 aminoacids; the second, of which we determined the entire sequence (16 exons), encodes for a predicted peptide (called αs2-II) of 168 aminoacids. Alternative splicing and genetic markers are reported for both genes.

Differences in the number of embryonic and pseudo-β-globin genes between HbA and HbB sheep

DNA samples obtained from 8 goats, 1 moufflon, and 84 sheep with HbA, HbAB, and HbB belonging to different breeds were digested withBamHI,EcoRI,HindIII andPstI and probed with the 5′ end of the goat εIV- and ψβZ-globin genes. Sheep homozygous for HbA show a different restriction pattern than sheep homozygous for HbB with each of these endonucleases. The main differences is that HbB sheep lack the εH and ψβX genes. These results, in addition to those previously obtained using a probe specific for β-globin genes, suggest that HbB sheep probably lack the preadult four-gene set. The DNAs from moufflon and sheep homozygous for HbA show indistinguishable restriction patterns. Furthermore, a number of restriction fragment length polymorphisms (RFLPs) are detected in the εIV and ωβZ DNA regions, and oneHindIII RFLP in the εVI DNA region.

Effects of the CSN1A(G) allele on the clotting time of cow milk and on the rheological properties of rennet-curd.

The aim of this research was to study the effects of the CSN1A(G) allele on the main rennet coagulation properties of milk. The study was carried out on individual milk samples with low alphas1-casein obtained from 19 Italian Brown cows heterozygous for the CSN1A(G) allele (seventeen CSN1A BG and two CSN1A CG) from four herds in the province of Parma (Italy). Control cows (sixteen CSN1A BB and three CSN1A BC) giving milk with normal alphas1-casein levels were chosen from within the same herds in order to establish pairs of cows with identical environment and management conditions, and comparable lactation stages and numbers. Individual milk samples from single pairs of cows with somatic cell counts and lactose and chloride levels within the normal ranges were collected and analysed in parallel. Rennet coagulation properties of milk were analysed using Formagraph and Gel Tester. Milk from low alphas1-casein cows was characterized by lower casein content, lower titratable acidity and a higher proportion of kappa-casein in total casein. The clotting time of this milk was approximately 23% lower than that obtained with milk from normal alphas1-casein cows. Rennet curd from low alphas1-casein milk was obtained more rapidly and had a higher final firmness: curd-firming time was approximately 35% lower and curd firmness measured 30 min after rennet addition was approximately 27% higher compared with that for normal alphas1-casein milk. In addition, curd from low alphas1-casein milk had a higher resistance to compression. These results suggest that, although a role for the CSN2 locus cannot be definitely excluded, the CSN1A(G) allele can considerably affect the main rennet coagulation properties of milk.

Comparison of goat, sheep, cattle and water buffalo leptin (LEP) genes and effects of the Intron 1 microsatellite polymorphism in goats

We report and compare the partial genomic sequence (from part of Intron 1 to part of Exon 3) of goat, sheep, cattle and water buffalo leptin (LEP) genes. Genomic DNA was obtained from leukocytes of 117 goats belonging to six breeds (Angora, Alpine, Garganica, Girgentana, Maltese and Red Syrian); 30 sheep belonging to five breeds (Altamura, Sarda, Apulian Merino, Leccese, Apennine) 50 water buffaloes and 43 Italian Friesian cattle. All the four species had a microsatellite region in Intron 1. According to the results of a population analysis, we observed 10, 5, and 2 alleles, in cattle, water buffalo and goats, respectively, in this region. No nucleotide variation was observed in sheep. The results of this study show that in Red Syrian goats the two alleles are associated with significantly different effects on β-hydroxybutyric acid (P = 0.04) and free thyroxine (P = 0.018) levels, and milk somatic cell counts (P = 0.034). The same microsatellite region was tendentially associated with variation in insulin-like growth factor-1 (P = 0.082) and triglycerides (P = 0.072) levels. The results of this study are further evidence for the role of leptin as an indicator of metabolism and mammary gland health in dairy ruminants.

ASPA 22nd Congress Book of Abstracts

than that caused by recognized “enterohaemorrhagic” STEC serogroups such as O157 and O111. More widespread use of PCRor enzyme-linked immunosorbent assay-based screening tests for the presence of STEC of any serogroup in animal samples will undoubtedly result in increased detection of similar non-O157 outbreaks in the future. This will provide more accurate data on the epidemiology of human STEC disease.

Variability of the IGF2 locus in the Suino Nero Lucano pig population and its effects on meat quality

The aim of this study was to analyse the polymorphisms in the two promoter regions, P1 and P2, of the porcine Insulin-like Growth Factor 2 (IGF2) gene and to investigate the effect of IGF2 genotypes on meat quality traits in the Italian autochthonous Suino Nero Lucano pig. Three polymorphic sites were analysed and only two of the eight potential haplotypes were observed in the Suino Nero Lucano pig population: A haplotype (–366A – –225G – –182C), and B haplotype (–366G – –225C – –182T). Muscle mass and meat quality characteristics were analysed in 30 castrated pigs (10 for each of the three IGF2 genotypes: A/A, A/B, and B/B). According to the results, B/B animals, at the same carcass weight, showed the highest Longissimus lumborum and Psoas weight (P < 0.05), whereas A/A animals showed a higher intramuscular fat percentage and lower Warner–Bratzler shear force, drip loss, and polyunsaturated fatty acids content. Meat from B/B animals showed also a higher L* value and myoglobin and deoxymyoglobin percentage compared with meat from A/A ones (P < 0.05).