Search

Two methods have been developed for the assessment of conservation priorities on the basis of molecular markers. According to the Weitzman approach, contributions to genetic diversity are derived from genetic distances between populations. Alternatively, diversity within and across populations is optimized by minimizing marker-estimated kinships. We have applied, for the first time, both methods to a comprehensive data set of 69 European cattle breeds, including all cosmopolitan breeds and several local breeds, for which genotypes of 30 microsatellite markers in 25-50 animals per breed have been obtained. Both methods were used to calculate the gain in diversity if a breed was added to a set of nine non-endangered breeds. Weitzman-derived diversities were confounded by genetic drift in isolated populations, which dominates the genetic distances but does not necessarily increase the conservation value of a breed. Marker-estimated kinships across populations were less disturbed by genetic drift than the Weitzman diversities and assigned high conservation values to Mediterranean breeds, which indeed have genetic histories that differ from the non-endangered breeds. Prospects and limitations of marker-assisted decisions on conservation priorities are discussed.

Made available in DSpace on 2014-12-03T13:07:04Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-04-17Bitstream added on 2014-12-03T13:24:33Z : No. of bitstreams: 1 WOS000335177200001.pdf: 750548 bytes, checksum: 075b52b143f984a79a48dec1b9a68ce6 (MD5) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Background: Descendants from the extinct aurochs (Bos primigenius), taurine (Bos taurus) and zebu cattle (Bos indicus) were domesticated 10,000 years ago in Southwestern and Southern Asia, respectively, and colonized the world undergoing complex events of admixture and selection. Molecular data, in particular genome-wide single nucleotide polymorphism (SNP) markers, can complement historic and archaeological records to elucidate these past events. However, SNP ascertainment in cattle has been optimized for taurine breeds, imposing limitations to the study of diversity in zebu cattle. As amplified fragment length polymorphism (AFLP) markers are discovered and genotyped as the samples are assayed, this type of marker is free of ascertainment bias. In order to obtain unbiased assessments of genetic differentiation and structure in taurine and zebu cattle, we analyzed a dataset of 135 AFLP markers in 1,593 samples from 13 zebu and 58 taurine breeds, representing nine continental areas.Results: We found a geographical pattern of expected heterozygosity in European taurine breeds decreasing with the distance from the domestication centre, arguing against a large-scale introgression from European or African aurochs. Zebu cattle were found to be at least as diverse as taurine cattle. Western African zebu cattle were found to have diverged more from Indian zebu than South American zebu. Model-based clustering and ancestry informative markers analyses suggested that this is due to taurine introgression. Although a large part of South American zebu cattle also descend from taurine cows, we did not detect significant levels of taurine ancestry in these breeds, probably because of systematic backcrossing with zebu bulls. Furthermore, limited zebu introgression was found in Podolian taurine breeds in Italy.Conclusions: The assessment of cattle diversity reported here contributes an unbiased global view to genetic differentiation and structure of taurine and zebu cattle populations, which is essential for an effective conservation of the bovine genetic resources. Univ Estadual Paulista, Fac Ciencias Agr & Vet, BR-14884900 Jaboticabal, SP, Brazil Univ Cattol Sacro Cuore, Inst Zootech, Piacenza, Italy Univ Cattol Sacro Cuore, BioDNA Biodivers & Ancient DNA Res Ctr, Piacenza, Italy Univ Utrecht, Fac Vet Med, Utrecht, Netherlands Univ Giessen, Inst Anim Breeding & Genet, D-35390 Giessen, Germany Univ Estadual Paulista, Fac Med Vet Aracatuba, BR-16050680 Aracatuba, SP, Brazil Univ Estadual Paulista, Fac Ciencias Agr & Vet, BR-14884900 Jaboticabal, SP, Brazil Univ Estadual Paulista, Fac Med Vet Aracatuba, BR-16050680 Aracatuba, SP, Brazil FAPESP: 11/16643-2 FAPESP: 13/12829-0

Chantier qualité GA Liste des auteurs de l'European Cattle Genetic Consortium, classés par pays : Austria: R. Baumung, S. Manatrinon, BOKU University, Vienna; Belgium: G. Mommens, University of Ghent, Merelbeke; Denmark: L.-E. Holm, Aarhus University, Tjele; K.B. Withen, B.V. Pedersen, P. Gravlund, University of Copenhagen, Copenhagen; Estonia: H. Viinalass, Estonian University of Life Sciences, Tartu; Finland: J. Kantanen, I. Tapio, M.H. Li, MTT, Jokioinen; France: K. Moazami-Goudarzi, M. Gautier, Denis Laloë, INRA, Jouy-en-Josas; A. Oulmouden, H. Levéziel, INRA, Limoges; P. Taberlet, Université Joseph Fourier et CNRS, Grenoble; Germany: B. Harlizius, School of Veterinary Medicine, Hannover; H. Simianer, H. Täubert, Georg-August-Universität, Göttingen; G. Erhardt, O. Jann, C. Weimann, E.-M. Prinzenberg, Justus-Liebig Universität, Giessen; I. Medugorac, A. Medugorac, M. Förster, Ludwig-Maximilians Universität, Munich; H.M. Mix, Naturschutz International, Grünheide; C. Looft, E. Kalm, Christian-Albrechts-Universität, Kiel; Ireland: D.G. Bradley, C.J. Edwards, D.E. MacHugh, A.R. Freeman, Trinity College, Dublin; Italy: P. Ajmone Marsan, R. Negrini, Università Cattolica del S. Cuore, Piacenza; M. Longeri, G. Ceriotti, M. Zanotti, Università degli Studi di Milano; D. Marletta, A. Criscione, Universita degli Studi di Catania, Catania; A. Valentini, C. Marchitelli, L. Pariset, M.C. Savarese, Università della Tuscia, Viterbo; F. Pilla, Università del Molise, Campobasso; Latvia: Z. Grislis, Latvia University of Agriculture, Jelgava; Lithuania: I. Miceikienė, Lithuanian Veterinary Academy, Kaunas; Netherlands: I.J. Nijman, Utrecht University; W. van Haeringen, L. van de Goor, Van Haeringen Laboratory, Wageningen; Norway: I. Olsaker, Norwegian School of Veterinary Science, Oslo; Portugal: C. Ginja, L.T.Gama, Instituto Nacional de Recursos Biológicos—INIA, Lisbon University, Lisboa; L.T. Gama, Instituto Nacional de Recursos Biológicos-INIA, I.P., Vale de Santarem; J.C. Mateus, Universidade de Trás-os-Montes e Alto Douro, Vila Real; A. Beja-Pereira, N. Ferrand, Oporto University; Russia: Z. Ivanova, R. Popov, I. Ammosov, Yakutian Research Institute of Agricultural Sciences, Yakutsk, Sakha; T. Kiselyova, All-Russian Research Institute for Farm Animals and Breeding, St. Petersburgh-Pushkin; N. Marzanov, All-Russian Research Institute of Animal Husbandry, Dubrovitsy; Serbia: S. Stojanovic, Ministry of Agriculture and Water Management, Belgrade; Slovenia: M. Simčič, P. Dovč, D.Kompan, University of Ljubljana, Domzale; Spain: S. Dunner, Universidad Complutense de Madrid; C. Rodellar, I. Martín-Burriel, Veterinary Faculty, Zaragoza; A. Sánchez, J. Piedrafita, Universitat Autònoma de Barcelona; P.J. Azor, J.V. Delgado, A. Martínez-Martínez, A. Molina, E. Rodero, University of Córdoba; Switzerland: G. Dolf, University of Berne; UK: J.L. Williams, P. Wiener, Roslin Institute; M.W. Bruford, T.C. Bray, Cardiff University, Cardiff; L. Alderson, Countrywide Livestock Ltd, Shrewsbury; USA: M.C.T. Penedo. University of California, Davis, CA; International audience; Classification of cattle breeds contributes to our understanding of the history of cattle and is essential for an effective conservation of genetic diversity. Here we review the various classifications over the last two centuries and compare the most recent classifications with genetic data. The classifications devised during the 19th to the late 20th century were in line with the Linnaean taxonomy and emphasized cranial or horn morphology. Subsequent classifications were based on coat color, geographic origin or molecular markers. Several theories were developed that linked breed characteristics either to a supposed ancestral aurochs subspecies or to a presumed ethnic origin. Most of the older classifications have now been discarded, but have introduced several Latin terms that are still in use. The most consistent classification was proposed in 1995 by Felius and emphasizes the geographic origin of breeds. This is largely in agreement with the breed clusters indicated by a biochemical and molecular genetic analysis, which reflect either groups of breeds with a common geographic origin or single breeds that have expanded by export and/or crossbreeding. We propose that this information is also relevant for managing the genetic diversity of cattle.

The Neolithic introduction of domestic cattle into Europe was followed by differential adaptation, selection, migration and genetic isolation, leading ultimately to the emergence of specialized breeds. We have studied the differentiation of European cattle by amplified fragment length polymorphism (AFLP) fingerprinting. Combining AFLP data sets from two laboratories yielded 81 biallelic polymorphic markers scored in 19-22 individual animals from 51 breeds. Model-based clustering differentiated Podolian cattle as well as French and Alpine breeds from other European cattle. AFLP genetic distances correlated well with microsatellite-based genetic distances calculated for the same breeds. However, the AFLP data emphasized the divergence of taurine and indicine cattle relative to the variation among European breeds and indicated an Eastern influence on Italian and Hungarian Podolian breeds. This probably reflects import from the East after the original introduction of domestic cattle into Europe. Our data suggest that Italian cattle breeds are relatively diverse at the DNA sequence level.

In farm animals candidate gene approach can be a useful tool to identify disease genes which afterwards can be included in selection programme analysis. The term arthrogryposis refers to a symptom complex that is characterised by congenital contractures. It consists of different degrees of flexion rigidity of phalangeal, metacarpophalangeal, carpal and metatarsophalangeal joints, Arthrogryposis has been reported in man, in farm animals and in pets. Several forms have been reported having a genetic origin in man. Recently in a pedigree study it has been indicated an autosomal recessive condition with congenital arthrogryposis in Suffolk lambs. In Brown Swiss and Holstein Friesian cattle congenital contractures associated with degeneration and loss of motor neurons in spinal cord, have been recorded and classified as Spinal Muscular Atrophy (SMA). Survival Motor Neuron gene (SMN) has been suggested as candidate gene for SMA. In man SMN shows a centromeric and a telomeric copy. Several exon or gene duplication deletions or point mutations, particularly in exon 7 and 8, have been recorded associated to arthrogryposis. In German Brown SMN cDNA has been sequenced (Genbank#AF035323) and mapped by Pietrowsky et al. in 1999 on chr20q12-13, by BLAST it shows high identity with human sequence. Eggen et al. in 1999 defined SMN mapping on chr20q14. Linkage between SMN and SMA has not yet identified in cattle. In the last 20 years National Association of Piedmont Cattle recorded a mean of 1.8% arthrogryposis cases. Incidence of 0.6% in females and 3.3% in males suggests the hypothesis of genetic disorder with incomplete penetrance in male. In our study we cloned and sequenced SMN gene starting from cDNA extracted from spinal cord samples of 2 animals: one Piedmont calf showing a severe clinical form of arthrogryposis and a normal Piedmont calf as a control. RT-PCR has been performed by a couple of primers we designed to amplify exon 1-6 region. Other primers have been designed to amplify, coupled with commercial adapter primers, the 5'end in a 5'RACE (Rapid Amplification of cDNA Ends). PCR products have been cloned in E. Coli by plasmid vector, sequenced by Big Dye Terminators chemical (Applied Biosystems) and analysed by BLAST® and Navigator software (Applied Biosysterns). By comparing the sequence available in Genbank with the sequences we obtained by RT-PCR, a silent substitution C->A in exon 6, both from health and affected calf, has been shown. By 5'RACE, > 50% of the clones in the affected calf showed a Single Nucleotide Polymorphism (SNP) ATG->TTG in exon 1 that should determine an aminoacid change Met->Leu (single point mutation M3L). In our clones this mutation is 100% associated to 9bp increase length of 5'UTR and to a silent mutation TTC-> TTT in exon 1 (Genbank#AF466194). No single point mutation or 5' end polymorphism have been shown in healthy control and in the remaining 50% of clones from the affected calf (Genbank#AF466193). 5'RACE PCR products from the affected animal, which were previously cloned, have been also directly sequenced to control the co-presence in the same product of both the two different sequences. Also in children SMA- affected an A2G point mutation associate to 5'UTR polymorphism has been described. Therefore it is possible to assume a pathogenic effect of exon 1 mutations both in man and cattle, as they are located in the SMN region where SP1 interacts to form the spliceosoma, a fundamental complex for cell splicing mechanism. Studies are in progress to assess this assumption in man (V.Funanage personal communication). Research supported by R.A.I.Z. (N. RZ-271). (Texte intégral)

Bovine tuberculosis is still present in different areas of Italy. Identification of resistant genotypes could be useful both to integrate the eradication programme and to improve a healthy-animal oriented selection. Moreover Mycobacterial infections are interesting models to study mechanisms of resistance to intracellular microbial antigens. As a candidate gene for M. bovis infection resistance in cattle we studied NRAMP1 gene (Natural Resistance Associated Macrophage Protein 1), formerly known as Bcg/Lsh/Ity gene. NRAMP1 gene owns to a family of proteins, the metal-ion carrier protein family, which is extremely conserved among different organisms from bacteria to superior vertebrates, suggesting a key role in all living organisms. Particularly NRAMP1 is involved in intracellular parasite immune control, including M. bovis. It could be involved in the phagosoma maturation process as it modulates the intraphagosoma content of ions, generating toxic radical and allowing the bacteriostatic and bactericidal action of macrophages. NRAMP1 gene is mapped on chromosome 2 in cattle (position q43-q44). It consists of 15 exons, codifying a 60kd membrane protein. NRAMP1 promoter region presents anchor sites for immune-active molecules, which represent NRAMP1 transcriptional factors. To amplify bovine NRAMP1 promoter we designed 8 primer pair set on ovine, murine and human sequences of conserved homologous regions. Using this primer panel we amplified genomic DNA from 10 cows out of 7 autochthonous Italian breeds. Particularly the animals were 4 Italian Friesian, 1 Aosta Red Pied, 1 Aosta Black Pied, 1 Aosta Chestnut, 1 Oropa Red Pied, 1 Rendena, 1 Burlina cattle. Out of the 8 primer pair panel, 3 primer pairs specifically amplified by PCR 3 different amplicons (995, 458 and 737pb), partially overlapping. Direct sequence of amplicons, carried on by Big Dye Terminators chemical (Applied Biosystems) and automatically analysed by ABI-Prism 377 (Applied Biosystems), allowed identifying a consensus sequence of 1491pb (Genbank# AY078403), which included part of bovine NRAMP1 exon1 (80bp) and 1411 bp at 5'end of exon1. Bovine consensus sequence of codifying region showed 100% homology with sheep when analysed by BLASTS. In addition, the promoter region showed a high homology with sheep promoter. Nevertheless, all the bovine sequences showed an insert of 51 pb, which lacks in sheep. No significant differences have been recorded among the different breeds, apart a g-a SNP (single nucleotide polymorphism) at position 731 pb in two Friesian cattle in heterozygous status order. Nevertheless, this SNP it is not located within regions, which represent transcription factor anchor loci. Further analysis on a larger sample could show a higher polymorphism of transcription factor anchor loci that could be related to different intracellular antigens response. Research supported by Italian MURST 40%-Cofin. 1999. (Texte intégral)

Despite the interest in aphid biology, information on chromatin organization of their holocentric chromosomes is still limited to few species. In order to fill this gap, we have performed an extensive survey on pea aphid mitotic chromosomes using both classical and molecular cytogenetic techniques. Our results after silver, CMA3 and DAPI-staining, C-banding and fluorescent in situ hybridization (FISH) using 28S rDNA and 5S rDNA as probes evidenced a tendency of repetitive DNAs to be concentrated on the X chromosomes. FISH experiments with the telomeric probe (TTAGG)n revealed bright hybridization signals on each telomere of all Acyrthosiphon pisum chromosomes. No interstitial signals were seen.

International audience

International audience

International audience