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P Peral-García

Publications and source records attributed to P Peral-García.

8 recordsLinked to original sources
PubMed2006

African matrilineages in American Creole cattle: evidence of two independent continental sources.

In order to clarify the historical origin and phylogeographic affinities of Creole cattle matrilineages throughout the American continent, we analysed published D-loop mtDNA sequences (n = 454) from Creole, Iberian and African cattle breeds. The Western European T3 haplogroup was the most common in American Creole cattle (63.6%), followed by the African T1 (32.4%) and the Near Eastern T2 haplogroups (4%). None of the sequences were found in Bos indicus types. Within the African T1 haplogroup there were two subclades, T1a and T1*, whose geographic distribution in America was clearly disjointed. T1a is a highly divergent clade originally reported for Creole cattle from Brazil and the Lesser Antilles, but whose geographic distribution in Africa remains unknown. In contrast, lineages attributable to T1* are restricted in America to the region colonized by the Spaniards. We propose a new hypothesis for the origins of Creole cattle that summarizes all previously published historical and genetic data. While the African T1* fraction in Creole cattle may have arrived in America through the Iberian breeds, the divergent T1a lineages may have been introduced by Portuguese and other European crowns from some unknown, not-yet-sampled African location. Additional molecular studies will be required for pinpointing the specific African regional source.

Africa↗
PubMed2005

Polymorphisms of the upstream regulatory region of the major histocompatibility complex DRB genes in domestic horses.

Sequence information was obtained on the variation of the ELA-DRB upstream regulatory region (URR) after polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) cloning and sequencing of approximately 220 bp upstream of the first exon of horse DRB genes. The sequence of the proximal URR of equine DRB is composed of highly conserved sequence motifs, showing the presence of the W, X, Y, CAAT and TATA conserved boxes of major histocompatibility complex (MHC) class II promoters. Five different polymorphic horse DRB promoter sequences were detected in five horse breeds. The results demonstrate the existence of polymorphism in the nucleotide sequences of the ELA-DRB URR, located in the functionally important conserved consensus sequences, the X2 box, the Y box and the TATA box, while conservation were observed in X1 and CAAT boxes. The nucleotide diversity among horse URRs was intermediate between that seen within human and mouse DRB promoters, suggesting the existence of another important source of variability in ELA-DRB genes. In addition, phylogenetic comparisons, identity analysis and sequence organization suggested that the reported sequences would correspond to an expressed ELA-DRB locus. However, further information about the functional significance of these promoter polymorphisms will probably be acquired through expression studies on the different sequences.

Animals↗
PubMed2004

Polymorphism in the bovine BOLA-DRB3 upstream regulatory regions detected through PCR-SSCP and DNA sequencing.

In the present work, we describe through polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and DNA sequencing the polymorphism within the URR-BoLA-DRB3 in 15 cattle breeds. In total, seven PCR-SSCP defined alleles were detected. The alignment of studied sequences showed six polymorphic sites (four transitions, one transversion and one deletion) in the interconsensus regions of the BoLA-DRB3 upstream regulatory region (URR), while the consensus boxes were invariant. Five out of six detected polymorphic sites were of one nucleotide substitution in the interconsensus regions. It is expected that these mutations do not affect significantly the level of expression. In contrast, the deletion observed in the sequence between CCAAT and TATA boxes could have some effect on affinity interactions between the promoter region and the transcription factors. The URR-BoLA-DRB3 DNA analyzed sequences showed moderate level of nucleotide diversity, high level of identity among them and were grouped in the same clade in the phylogenetic tree. In addition, the phylogenetic tree, the similarity analysis and the sequence structure confirmed that the fragment analyzed in this study corresponds to the URR-BoLA-DRB3. The functional role of the observed polymorphic sites among the regulatory motifs in bovine needs to be analyzed and confirmed by means of gene expression assays.

Animals↗
PubMed2003

Analysis of ELA-DQB exon 2 polymorphism in Argentine Creole horses by PCR-RFLP and PCR-SSCP.

The second exon of equine leucocyte antigen (ELA)-DQB genes was amplified from genomic DNA of 32 Argentine Creole horses by PCR. Amplified DNA was analysed by PCR-restriction fragment length polymorphism (RFLP) and PCR-single-strand conformation polymorphism (SSCP). The PCR-RFLP analysis revealed two HaeIII patterns, four RsaI patterns, five MspI patterns and two HinfI patterns. EcoRI showed no variation in the analysed sample. Additional patterns that did not account for known exon 2 DNA sequences were observed, suggesting the existence of novel ELA-DQB alleles. PCR-SSCP analysis exhibited seven different band patterns, and the number of bands per animal ranged from four to nine. Both methods indicated that at least two DQB genes are present. The presence of more than two alleles in each animal showed that the primers employed in this work are not specific for a unique DQB locus. The improvement of this PCR-RFLP method should provide a simple and rapid technique for an accurate definition of ELA-DQB typing in horses.

Animals↗
PubMed2002

Greater genetic variability in Argentine Creole than in Thoroughbred horses based on serum protein polymorphisms.

Genetic polymorphism was analyzed for five blood proteins: albumin - Al, esterase - Es, alpha(1)B-glycoprotein - Xk, transferrin - Tf and hemoglobin - Hb in 200 Thoroughbred (TB) and 124 Argentine Creole (AC) horses. Of the five systems examined, Tf and Hb were not in Hardy-Weinberg equilibrium in either breed and Es was not in equilibrium in the Creole breed. Genetic variability, estimated as average heterozygosity, was higher in AC (H = 0.585 +/- 0.131) than in TB (H = 0.353 +/- 0.065). The genetic differentiation between these two populations (F(ST)) was 0.109. Thus, of the total genetic differences between breeds, the proportion of genetic variation attributable to breed differences was about 10%; the remaining 90% was due to individual variation within breeds. The high degree of genetic variability seen in Argentine Creole horses could be a consequence of natural selection. Selection of TB through the centuries has most likely modified the gene pool of the ancestral population, with a consequent reduction in variability at certain loci. Probably, different mechanisms exist for maintaining polymorphism at these loci in TB and in AC horses. Heterozygosity may have played a fundamental role in adaptation.

Animals↗
PubMed2001

Genetic variation of the second exon of ELA-DRB genes in Argentine Creole horses.

Genetic variation in the equine leucocyte antigen-DRB (ELA-DRB) second exon was investigated using polymerase chain reaction (PCR) amplification, restriction fragment length polymorphism (RFLP) of PCR products (PCR-RFLP) and deoxyribonucleic acid (DNA) sequencing. Eight distinct PCR-RFLP patterns could be identified in the studied Argentine Creole (AC) horses. The number of observed patterns per individual ranged from four to six, thus confirming the presence of multiple DRB copies in AC horses. Three PCR-RFLP alleles and three new sequences were identified. The estimated rates of synonymous and non-synonymous substitutions among ELA-DRB exon 2 sequences were higher within the antigen recognition site (ABS) than on the non-ABS. Phylogenetic analysis showed that the nucleotide sequences clustered in two main groups, while some sequences were not included in either group. Finally, the identification of the number of alleles per animal, the phylogenetic and segregation analyses allowed us to explain the number of ELA-DRB loci. However, it was not possible to identify specific alleles with specific loci.

Alleles↗
PubMed2001

DNA typing in a cattle stealing case.

DNA profiling was used as probative evidence in a cattle stealing case. The carcasses of the dead animals were found from a report and a farmer recognized the remains as those corresponding to the stolen animals by the farm mark on the coat. Those remains were collected as reference samples. Meat pieces were sequestered from a butchery and then sent to our Laboratory by the Justice Department of Buenos Aires (Argentine) to perform a DNA comparative analysis with the reference. Matches were found between the evidences and the references, supporting the hypothesis that the meat pieces had been obtained from the stolen animals. The butcher was suspected of stealing animals but no direct incrimination had been made yet.

Alleles↗