Microsatellite mapping of QTL affecting growth, feed consumption, egg production, tonic immobility and body temperature of Japanese quail

BACKGROUND: The Japanese quail (Coturnix japonica) is both an animal model in biology and a commercial bird for egg and meat production. Modern research developments with this bird, however, have been slowed down by the limited information that is available on the genetics of the Japanese quail. Recently, quail genetic maps with microsatellites and AFLP have been produced which open the way to comparative works with the chicken (Gallus gallus), and to QTL detection for a variety of traits. The purpose of this work was to detect for the first time QTL for commercial traits and for more basic characters in an F2 experiment with 434 female quail, and to compare the nature and the position of the detected QTL with those from the first chicken genome scans carried out during the last few years. RESULTS: Genome-wide significant or suggestive QTL were found for clutch length, body weight and feed intake on CJA01, age at first egg and egg number on CJA06, and eggshell weight and residual feed intake on CJA20, with possible pleiotropy for the QTL affecting body weight and feed intake, and egg number and age at first egg. A suggestive QTL was found for tonic immobility on CJA01, and chromosome-wide significant QTL for body temperature were detected on CJA01 and CJA03. Other chromosome-wide significant QTL were found on CJA02, CJA05, CJA09 and CJA14. Parent-of-origin effects were found for QTL for body weight and feed intake on CJA01. CONCLUSION: Despite its limited length, the first quail microsatellite map was useful to detect new QTL for rarely reported traits, like residual feed intake, and to help establish some correspondence between the QTL for feed intake, body weight and tonic immobility detected in the present work and those reported on GGA01 in the chicken. Further comparative work is now possible in order to better estimate and understand the genetic similarities and differences of these two Phasianidae species

Integrated maps in quail (Coturnix japonica) confirm the high degree of synteny conservation with chicken (Gallus gallus) despite 35 million years of divergence

BACKGROUND: By comparing the quail genome with that of chicken, chromosome rearrangements that have occurred in these two galliform species over 35 million years of evolution can be detected. From a more practical point of view, the definition of conserved syntenies helps to predict the position of genes in quail, based on information taken from the chicken sequence, thus enhancing the utility of this species in biological studies through a better knowledge of its genome structure. A microsatellite and an Amplified Fragment Length Polymorphism (AFLP) genetic map were previously published for quail, as well as comparative cytogenetic data with chicken for macrochromosomes. Quail genomics will benefit from the extension and the integration of these maps. RESULTS: The integrated linkage map presented here is based on segregation analysis of both anonymous markers and functional gene loci in 1,050 quail from three independent F2 populations. Ninety-two loci are resolved into 14 autosomal linkage groups and a Z chromosome-specific linkage group, aligned with the quail AFLP map. The size of linkage groups ranges from 7.8 cM to 274.8 cM. The total map distance covers 904.3 cM with an average spacing of 9.7 cM between loci. The coverage is not complete, as macrochromosome CJA08, the gonosome CJAW and 23 microchromosomes have no marker assigned yet. Significant sequence identities of quail markers with chicken enabled the alignment of the quail linkage groups on the chicken genome sequence assembly. This, together with interspecific Fluorescence In Situ Hybridization (FISH), revealed very high similarities in marker order between the two species for the eight macrochromosomes and the 14 microchromosomes studied. CONCLUSION: Integrating the two microsatellite and the AFLP quail genetic maps greatly enhances the quality of the resulting information and will thus facilitate the identification of Quantitative Trait Loci (QTL). The alignment with the chicken chromosomes confirms the high conservation of gene order that was expected between the two species for macrochromosomes. By extending the comparative study to the microchromosomes, we suggest that a wealth of information can be mined in chicken, to be used for genome analyses in quail

Search for QTL affecting the shape of the egg laying curve of the Japanese quail

BACKGROUND: Egg production is of critical importance in birds not only for their reproduction but also for human consumption as the egg is a highly nutritive and balanced food. Consequently, laying in poultry has been improved through selection to increase the total number of eggs laid per hen. This number is the cumulative result of the oviposition, a cyclic and repeated process which leads to a pattern over time (the egg laying curve) which can be modelled and described individually. Unlike the total egg number which compounds all variations, the shape of the curve gives information on the different phases of egg laying, and its genetic analysis using molecular markers might contribute to understand better the underlying mechanisms. The purpose of this study was to perform the first QTL search for traits involved in shaping the egg laying curve, in an F(2 )experiment with 359 female Japanese quail. RESULTS: Eight QTL were found on five autosomes, and six of them could be directly associated with egg production traits, although none was significant at the genome-wide level. One of them (on CJA13) had an effect on the first part of the laying curve, before the production peak. Another one (on CJA06) was related to the central part of the curve when laying is maintained at a high level, and the four others (on CJA05, CJA10 and CJA14) acted on the last part of the curve where persistency is determinant. The QTL for the central part of the curve was mapped at the same position on CJA06 than a genome-wide significant QTL for total egg number detected previously in the same F(2). CONCLUSION: Despite its limited scope (number of microsatellites, size of the phenotypic data set), this work has shown that it was possible to use the individual egg laying data collected daily to find new QTL which affect the shape of the egg laying curve. Beyond the present results, this new approach could also be applied to longitudinal traits in other species, like growth and lactation in ruminants, for which good marker coverage of the genome and theoretical models with a biological significance are available

Genetic Diversity of Helmeted Guineafowl (Numida meleagris) Based on Microsatellite Analysis

Characterization of the genetic diversity of indigenous animal populations is a prerequisite for providing needed information for the conservation of useful genotypes against future uncertainties in the face of daunting global challenges such as climate change, emerging diseases, population growth, and rising consumer demands. In this study, a total of 232 helmeted guineafowls (Numida meleagris) sampled from three populations in Ghana, one population in Benin and two populations in Japan were genotyped across six autosomal microsatellite loci. Three vulturine guineafowls (Acryllium vulturinum) were included as outgroup. A total of 66 alleles were observed with an average of 11.0 alleles per locus. The indigenous West African populations (Ghana and Benin) were more genetically diverse (Na=9.8; Ho=0.457) but less differentiated (FST=0.162) compared to the non-indigenous populations in Japan (Na=4.2; Ho=0.236; FST=0.389). The information from this study would be useful for selection and improvement programs necessary for the sustainable exploitation of this agriculturally and commercially important species as a suitable alternative to chicken

Sequence and immunologic conservation of Anaplasma marginale OmpA within strains from Ghana as compared to the predominant OmpA variant.

A primary challenge in developing effective vaccines against obligate, intracellular, bacterial tick-borne pathogens that establish persistent infection is the identification of antigens that cross protect against multiple strains. In the case of Anaplasma marginale, the most prevalent tick-borne pathogen of cattle found worldwide, OmpA is an adhesin and thus a promising vaccine candidate. We sequenced ompA from cattle throughout Ghana naturally infected with A. marginale in order to determine the degree of variation in this gene in an area of suspected high genetic diversity. We compared the Ghanaian sequences with those available from N. America, Mexico, Australia and Puerto Rico. When considering only amino acid changes, three unique Ghanaian OmpA variants were identified. In comparison, strains from all other geographic regions, except one, shared a single OmpA variant, Variant 1, which differed from the Ghanaian variants. Next, using recombinant OmpA based on Variant 1, we determined that amino acid differences in OmpA in Ghanaian cattle as compared to OmpA Variant 1 did not alter the binding capacity of antibody directed against OmpA Variant 1, supporting the value of OmpA as a highly conserved vaccine candidate

Caracteristiques Du Système D'exploitation Des Poulets Locaux Dans Deux Zones Agro-Ecologiques (Sud Forestier Et Centre Savanicole) De La Côte D’Ivoire

Les poulets locaux, malgré leur rôle important dans l’aviculture ivoirienne, souffrent de leur faible productivité. Pour contribuer à l’amélioration de leur productivité, une étude descriptive a été réalisée sur son élevage auprès 206 paysans natifs de deux zones agro-écologiques à l’aide d’un questionnaire. Les résultats indiquent les paysans exploitent les poulets locaux dans un système exclusivement extensif. L’aviculture villageoise est une activité dominée par les hommes (79,60 %) et la considérant comme secondaire (97 %). La plupart de ces aviculteurs sont analphabètes (52,5 %). La rusticité et la qualité organoleptique des produits constituent les principales motivations en faveur de cet élevage dans 82 % cas en moyenne. Ils ont débuté l’élevage par achat (59 %) d’un petit noyau initial, par don ou par héritage (41 %) en zone de forêt et par confiage (60 %) en zone de savane. La 1ère ponte d’une poulette intervient en moyenne à 6 mois d’âge (52,5 %). Un faible effectif (23 poulets) composé en majorité de jeunes sujets (55,21 %), de poules (33,19 %) et de coqs (11,40%) a été observé dans les cheptels. Le plein air intégral (73,30 %) a été le mode privilégié d’élevage en zone de savane. Les épizooties (54,35 %) et les prédateurs (38 %) ont été les premières causes de mortalité. Les produits d'élevage issus de ce système ont été utilisés en autoconsommation (62 %) en zone de forêt et vendus (65 %) en zone de savane. La levée des contraintes caractérisant le système le système extensif pourrait aider à l’amélioration de la productivité des poules locales. Local chickens play an important role in Ivorian poultry farming, but this animal resource suffers from its low productivity. In order to contribute to the improvement of this productivity, a descriptive study was carried out on its breeding among two hundred and six (206) farmers who were native to two agro-ecological zones using a structured questionnaire. The results indicate that these farmers are exploiting local chickens in an extensive system exclusively. Village poultry farming is an activity dominated by men (79.60%) and considered secondary (97%). Most of these poultry farmers are illiterate (52.5%) and the rusticity and organoleptic quality of the products are the main motivations for this breeding in an average of 82% cases. They began breeding by purchasing a small nucleus (59%), by gifts or inheritance (41%) in the Forest zone and by entrusting (60%) in the Savannah zone. The first laying of a pullet occurs on average at 6 months of age (52.5%) and the early pullet lays its first eggs between 4 and 6 months (13%). A few chickens (23), the majority of which were youngsters (55.21%), hens (33.19%) and roosters (11.40%), were observed in the flocks. In Savannah areas, free-range rearing (73.30%) was the preferred method of rearing. Epizootics (54.35%) and predators (38%) were the main causes of mortality. The livestock products from this system were used for self-consumption (62%) in the forest zone and sold (65%) in the Savannah zone. Removing the constraints that characterize the extensive system could help to improve the productivity of local chickens. &nbsp

Evidence for introgressive hybridization of wild common quail (Coturnix coturnix) by domesticated Japanese quail (Coturnix japonica) in France

International audienceMany cases of introgressive hybridization have been reported among birds, particularly following introduction to the natural environment of individuals belonging to non-native similar taxa. This appears to be the case for common quail (Coturnix coturnix) in France where wild populations artificially come into contact with domesticated Japanese quail (Coturnix japonica) raised for meat and egg production but sometimes released for hunting purposes. In order to highlight the possible existence of gene flows between both taxa, a comparison of nuclear (25 microsatellite loci) and mitochondrial (sequencing and RFLP) DNA polymorphisms was performed on 375 common quails (from France, Spain and Morocco) and 140 Japanese quails (from France and Japan). Genetic diversity was assessed, and analyses (Factorial Correspondence Analysis, Bayesian admixture) of molecular polymorphisms revealed clear differentiation between the two taxa, making it possible to detect for hybrids among quails sampled in the wild. Eight birds expected to be common quail were found to be two pure Japanese quail, one probable backcross to C. japonica, three F1/F2 hybrids, and two probable backcrosses to Coturnix coturnix. These results show that Japanese quails were released and suggest that the two taxa hybridize in the wild. They confirm the urgent need for preventing the release of pure Japanese or hybrid quails to preserve the genetic integrity of C. coturnix. The tools developed for this study should be useful for accurate monitoring of wild quail populations within the framework of avifauna management programs