J. Jordana

Genetic diversity measures of local European beef cattle breeds for conservation purposes

This study was undertaken to determine the genetic structure, evolutionary relationships, and the genetic diversity among 18 local cattle breeds from Spain, Portugal, and France using 16 microsatellites. Heterozygosities, estimates of Fst, genetic distances, multivariate and diversity analyses, and assignment tests were performed. Heterozygosities ranged from 0.54 in the Pirenaica breed to 0.72 in the Barrosã breed. Seven percent of the total genetic variability can be attributed to differences among breeds (mean Fst = 0.07; P < 0.01). Five different genetic distances were computed and compared with no correlation found to be significantly different from 0 between distances based on the effective size of the population and those which use the size of the alleles. The Weitzman recursive approach and a multivariate analysis were used to measure the contribution of the breeds diversity. The Weitzman approach suggests that the most important breeds to be preserved are those grouped into two clusters: the cluster formed by the Mirandesa and Alistana breeds and that of the Sayaguesa and Tudanca breeds. The hypothetical extinction of one of those clusters represents a 17% loss of diversity. A correspondence analysis not only distinguished four breed groups but also confirmed results of previous studies classifying the important breeds contributing to diversity. In addition, the variation between breeds was sufficiently high so as to allow individuals to be assigned to their breed of origin with a probability of 99% for simulated samples.

Genetic diversity in Spanish donkey breeds using microsatellite DNA markers

Genetic diversity at 13 equine microsatellite loci was compared in five endangered Spanish donkey breeds: Andaluza, Catalana, Mallorquina, Encartaciones and Zamorano-Leonesa. All of the equine microsatellites used in this study were amplified and were polymorphic in the domestic donkey breeds with the exception of HMS1, which was monomorphic, and ASB2, which failed to amplify. Allele number, frequency distributions and mean heterozygosities were very similar among the Spanish donkey breeds. The unbiased expected heterozygosity (HE) over all the populations varied between 0.637 and 0.684 in this study. The low GST value showed that only 3.6% of the diversity was between breeds (P < 0.01). Significant deviations from Hardy-Weinberg equilibrium were shown for a number of locus-population combinations, except HMS5 that showed agreement in all analysed populations. The cumulative exclusion probability (PE) was 0.999 in each breed, suggesting that the loci would be suitable for donkey parentage testing. The constructed dendrogram from the DA distance matrix showed little differentiation between Spanish breeds, but great differentiation between them and the Moroccan ass and also with the horse, used as an outgroup. These results confirm the potential use of equine microsatellite loci as a tool for genetic studies in domestic donkey populations, which could also be useful for conservation plans.

Gene frequencies of caprine αs1-casein polymorphism in Spanish goat breeds

Abstract Using electrophoretic techniques (PAGE-SDS and IEF), we report allelic frequencies of caprine α s1 -casein (Cn) locus in four Spanish milking breeds: Murciana-Granadina, Malaguena, Payoya and Canaria . The E allele (intermediate content of α s1 -Cn in milk) was predominant in dairy breeds Murciana-Granadina , E:0.59; Malaguena , E:0.65 and Payoya , E:0.76, while alleles A and B (high content of α s1 -Cn) were more frequent in the Canaria dairy breed (A:0.28 and B:0.32). Among the Spanish breeds, Canaria represents a particular case where 60% of the alleles were of the high type (A and B). The ethnical group Canaria Palmera was particularly high in the frequency of alleles A and B (91%) very similar to the Italian Garganica breed (98%). The low frequency of F allele (reduced level of α s1 -Cn) in Spanish breeds ( Murciana-Granadina , F:0.08; Malaguena , F:0.04; Payoya , F:0.00 and Canaria , F: and Saanen breeds. It is important to note that in the Payoya breed no low or null alleles (F, D, 0) were detected. It seems unlikely that genetic selection for milk production has had a significant influence in determining the α s1 -Cn allelic distribution in goat populations. The direct relationship existing between these allelic variants and differences in the Cn content and in the physico-chemical properties of milk, can be used as a tool in the improvement of milk processing quality and cheese yields of Spanish milking breeds.

Short communication: Effect of αS1-casein (CSN1S1) and κ-casein (CSN3) genotypes on milk composition in Murciano-Granadina goats

The effects of the caprine alpha(S1)-casein (CSN1S1) polymorphisms on milk quality have been widely demonstrated. However, much less is known about the consequences of the kappa-casein (CSN3) genotype on milk composition in goats. Moreover, the occurrence of interactions between CSN3 and CSN1S1 genotypes has not been investigated. In this study, an association analysis between CSN1S1 and CSN3 genotypes and milk quality traits was performed in 89 Murciano-Granadina goats. Total milk yield as well as total protein, fat, solids-not-fat, lactose, alpha(S1)-casein (CSN1S1), and alpha(S2)-casein (CSN1S2) contents were recorded every other month during a whole lactation (316 observations). Data analysis using a linear mixed model for repeated observations revealed no interaction between the CSN1S1 and CSN3 genotypes. With regard to the effect of the CSN3 locus, AB and BB genotypes were significantly associated with higher levels of total casein and protein content compared with the AA CSN3 genotype. In strong contrast with French breeds, the CSN1S1 genotype did not affect protein, casein, and fat concentrations in Murciano-Granadina goats. These results highlight the importance of taking into consideration the CSN3 genotype when performing selection for milk composition in dairy goats.

Low diversity in the major histocompatibility complex class II DRB1 gene of the Spanish ibex, Capra pyrenaica.

During the last two centuries, the Spanish ibex (Capra pyrenaica) has shown a significant demographic decline as a result of the progressive destruction of its natural habitat, disease epidemics, and uncontrolled hunting. Partial sequencing of the class II MHC DRB1 gene revealed that the Spanish ibex has remarkably low levels of genetic variation at this locus, with only six different DRB1 alleles and an observed heterozygosity of 0.429–0.579. The rates of nonsynonymous vs synonymous substitutions were significantly different in the peptide-binding region (dN/dS=5.347, P=0.002), a feature that indicates that the DRB1 gene is under positive selection. A phylogenetic analysis of the Spanish ibex and a set of domestic goat DRB1 alleles revealed that the reported sequences represent four major allelic lineages. The limited allelic repertoire of the DRB1 gene in the Spanish ibex is likely the direct result of the recent history of population bottlenecks and marked demographic decline of this species. A genetic survey of 13 microsatellite loci was consistent with this idea. The Spanish ibex subspecies C. p. hispanica and C. p. victoriae consistently showed considerably lower levels of microsatellite heterozygosity (Ho=0.184–0.231) and allelic diversity (mean number of alleles per locus=2–2.4) than those reported in other wild ruminants. This study demonstrates the significance of both natural selection and the demographic history of populations in determining patterns of genetic variation at MHC loci. In addition, our results emphasize the importance of locally adapted populations for the preservation of genetic diversity.

Diagnosis and epidemiology of Brucella ovis infection in rams

Abstract The relationship between clinical, serological and bacteriological diagnostic criteria have been determined in Brucella ovis culture-positive and Brucella free control rams and also in 110 field rams belonging to 13 different flocks, in which an epidemiological survey was conducted. In control rams, a direct relationship was found among the existence of positive bacteriological results and the presence of a positive serological response in the gel diffusion (GD) and complement fixation (CF) tests for B. ovis. In field rams, the presence of macroscopic testicular alterations (MTA) caused by B. ovis was correlated with bacteriological and serological results. The percentage of reactors and the percentage of rams showing MTA was not related to the size of flocks nor to the ratios of ram/ewes. The prevalence of B. ovis infection was significantly higher in rams from imported breeds than in those from local ones. Moreover, the younger and the oldest rams showed the lowest prevalence of B. ovis infection, but the age of rams did not influence the prevalence of MTA not caused by B. ovis.

Analysis of genetic relationships from morphological characters in Spanish goat breeds

Abstract Relationships between ten Spanish goat breeds were studied using qualitative and quantitative analyses of data from 26 morphological characters. The average morphological distance between breeds, measured as MCD (mean character difference), has a value of (0.6615 ± 0.1042), with extreme values of 0.4231 between Negra Serrana-Blanca Celtiberica and Malaguena-Canaria pairs, and 0.8846 for the Canaria-Blanca Andaluza pair. Two well-defined clusters can be appreciated in the dendrograms. One formed by Malaguena, Canaria, Verata and Murciano-Granadina breeds, and the other one composed by Negra Serrana, Blanca Celtiberica, Retinta Extremena and Blanca Andaluza breeds. Pirenaica and Guadarrama breeds are included in one or the other cluster depending on the program used (PAUP vs. PHYLIP). Relationships between the goat breeds and their possible ancestral origins are discussed in relation to classifications made by other authors. Although these results agree with results obtained with blood markers, it is difficult to interpret the phylogenetic relationships between goat breeds in relation to ancestral trunks. However, the racial classifications obtained adjust perfectly to the three production systems (meat, milk, and dual-purpose aptitudes).

Effects of α s1-casein (CSN1S1) and κ-casein (CSN3) genotypes on milk coagulation properties in Murciano-Granadina goats.

The effects of the caprine α s1-casein (CSN1S1) polymorphisms on milk quality and cheese yield have been widely studied in French and Italian goat breeds. Much less is known about the consequences of κ-casein (CSN3) genotype on the technological and coagulation properties of goat milk. In the current study, we have performed an association analysis between polymorphisms at the goat CSN1S1 and CSN3 genes and milk coagulation (rennet coagulation time, curdling rate and curd firmness) and technological (time to cutting of curd and cheese yield) properties. In this analysis, we have included 193 records from 74 Murciano-Granadina goats (with genotypes constituted by different combinations of alleles B, E and F of the gene CSN1S1 and alleles A and B of the gene CSN3) distributed in three herds, which were collected bimonthly during a whole lactation. Data analysis, using a linear mixed model for repeated observations, revealed significant associations between CSN1S1 genotypes and the rate of the curdling process. In this way, milk from EE goats had a significantly higher curdling rate than milk from BB individuals (P<0·05). Contrary to previous experiments performed in French breeds, cheese yield was not significantly different in BB, EE and EF goats. Moreover, we have shown that CSN3 genotype has a significant effect on the rennet coagulation time (BB>AB, P<0·05) but not on cheese yield. No interaction between the CSN1S1 and CSN3 genotypes was observed.

Hierarchical analysis of genetic structure in Spanish donkey breeds using microsatellite markers

The hierarchical population structure of five, native-Spanish donkey breeds (Andaluza, Catalana, Mallorquina, Encartaciones and Zamorano-Leonesa) has been studied using F-statistics. In addition, nine Moroccan asses and 24 Merens breed horses were included in the analysis. Data came from 15 DNA microsatellites. The analysis shows that Spanish donkeys are substructured at both hierarchical levels studied, among breeds and within breeds (between subpopulations). In the whole population, the deficit of heterozygotes was estimated to be about 21%. The fixation indices corresponding to differences between breeds, subpopulations within breeds, and within subpopulations were estimated to be 6.4%, 3.5% and 3.0%, respectively. The dendrogram obtained shows that the Andaluza and the Moroccan ass form a separate cluster from the northern Spanish breeds (Catalana, Encartaciones, Mallorquina and Zamorana-Leonesa). These groupings coincide with those obtained from historical and archaeological data.

Effect of αs1-casein (CSN1S1) genotype on milk CSN1S1 content in Malagueña and Murciano-Granadina goats

There is substantial evidence showing that the polymorphism of the goat alphas1-casein (CSN1S1) gene has a major effect on milk protein, casein and fat content as well as on cheese yield. However, its influence on the synthesis rate of CSN1S1 has been less studied, with measurements only available in French breeds. In this article, we have measured milk CSN1S1 content in 89 Malagueña and 138 Murciano-Granadina goats with 305 and 460 phenotypic registers, respectively. In the Malagueña breed, average values of CSN1S1 content estimated for BB, BF, EE and FF genotypes were 6.94+/-0.38, 5.36+/-0.22, 4.58+/-0.13 and 3.98+/-0.27 g/l, respectively, being all significantly different (P<0.05). Conversely, in the Murciano-Granadina breed only the BB genotype (8.50+/-0.60 g/l) was significantly associated with increased levels of CSN1S1 (P<0.05), whereas BF (6.56+/-0.82 g/l), EE (6.39+/-0.60 g/l) and EF (6.91+/-0.76 g/l) genotypes displayed non-significant differences when compared with each other. Our results highlight the existence of breed-specific genetic and/or environmental factors modulating the impact of the CSN1S1 gene polymorphism on the synthesis rate of the corresponding protein.