Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 50
Filtrar
Mais filtros








Base de dados
Intervalo de ano de publicação
1.
PLoS Genet ; 19(4): e1010724, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-37068079

RESUMO

The biochemical pathway regulating the synthesis of yellow/red pheomelanin is less well characterized than the synthesis of black/brown eumelanin. Inhibitor of gold (IG phenotype) is a plumage colour variant in chicken that provides an opportunity to further explore this pathway since the recessive allele (IG) at this locus is associated with a defect in the production of pheomelanin. IG/IG homozygotes display a marked dilution of red pheomelanin pigmentation, whilst black pigmentation (eumelanin) is only slightly affected. Here we show that a 2-base pair insertion (frame-shift mutation) in the 5th exon of the Catechol-O-methyltransferase containing domain 1 gene (COMTD1), expected to cause a complete or partial loss-of-function of the COMTD1 enzyme, shows complete concordance with the IG phenotype within and across breeds. We show that the COMTD1 protein is localized to mitochondria in pigment cells. Knockout of Comtd1 in a mouse melanocytic cell line results in a reduction in pheomelanin metabolites and significant alterations in metabolites of glutamate/glutathione, riboflavin, and the tricarboxylic acid cycle. Furthermore, COMTD1 overexpression enhanced cellular proliferation following chemical-induced transfection, a potential inducer of oxidative stress. These observations suggest that COMTD1 plays a protective role for melanocytes against oxidative stress and that this supports their ability to produce pheomelanin.


Assuntos
Catecol O-Metiltransferase , Galinhas , Camundongos , Animais , Galinhas/genética , Catecol O-Metiltransferase/genética , Camundongos Knockout , Melaninas/metabolismo , Pigmentação/genética , Mutação da Fase de Leitura
2.
Genet Sel Evol ; 55(1): 28, 2023 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-37076793

RESUMO

BACKGROUND: Genetic diversity is a necessary condition for populations to evolve under natural adaptation, artificial selection, or both. However, genetic diversity is often threatened, in particular in domestic animal populations where artificial selection, genetic drift and inbreeding are strong. In this context, cryopreserved genetic resources are a promising option to reintroduce lost variants and to limit inbreeding. However, while the use of ancient genetic resources is more common in plant breeding, it is less documented in animals due to a longer generation interval, making it difficult to fill the gap in performance due to continuous selection. This study investigates one of the only concrete cases available in animals, for which cryopreserved semen from a bull born in 1977 in a lost lineage was introduced into the breeding scheme of a French local dairy cattle breed, the Abondance breed, more than 20 years later. RESULTS: We found that this re-introduced bull was genetically distinct with respect to the current population and thus allowed part of the genetic diversity lost over time to be restored. The expected negative gap in milk production due to continuous selection was absorbed in a few years by preferential mating with elite cows. Moreover, the re-use of this bull more than two decades later did not increase the level of inbreeding, and even tended to reduce it by avoiding mating with relatives. Finally, the reintroduction of a bull from a lost lineage in the breeding scheme allowed for improved performance for reproductive abilities, a trait that was less subject to selection in the past. CONCLUSIONS: The use of cryopreserved material is an efficient way to manage the genetic diversity of an animal population, by mitigating the effects of both inbreeding and strong selection. However, attention should be paid to mating of animals to limit the disadvantages associated with incorporating original genetic material, notably a discrepancy in the breeding values for selected traits or an increase in inbreeding. Therefore, careful characterization of the genetic resources available in cryobanks could help to ensure the sustainable management of populations, in particular local or small populations. These results could also be transferred to the conservation of wild threatened populations.


Assuntos
Endogamia , Seleção Genética , Feminino , Bovinos/genética , Animais , Masculino , Fenótipo , Sêmen , Variação Genética
3.
Genet Sel Evol ; 54(1): 56, 2022 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-35922745

RESUMO

BACKGROUND: On-going climate change will drastically modify agriculture in the future, with a need for more sustainable systems, in particular regarding animal production. In this context, genetic diversity is a key factor for adaptation to new conditions: local breeds likely harbor unique adaptive features and represent a key component of diversity to reach resilience. However, local breeds often suffer from small population sizes, which puts these valuable resources at risk of extinction. In chickens, population management programs were initiated a few decades ago in France, relying on a particular niche market that aims at promoting and protecting local breeds. We conducted a unique comprehensive study of 22 French local breeds, along with four commercial lines, to evaluate their genetic conservation status and the efficiency of the population management programs. RESULTS: Using a 57K single nucleotide polymorphism (SNP) chip, we demonstrated that both the between- and within-breed genetic diversity levels are high in the French local chicken populations. Diversity is mainly structured according to the breeds' selection and history. Nevertheless, we observed a prominent sub-structuring of breeds according to farmers' practices in terms of exchange, leading to more or less isolated flocks. By analysing demographic parameters and molecular information, we showed that consistent management programs are efficient in conserving genetic diversity, since breeds that integrated such programs earlier had older inbreeding. CONCLUSIONS: Management programs of French local chicken breeds have maintained their genetic diversity at a good level. We recommend that future programs sample as many individuals as possible, with emphasis on both males and females from the start, and focus on a quick and strong increase of population size while conserving as many families as possible. We also stress the usefulness of molecular tools to monitor small populations for which pedigrees are not always available. Finally, the breed appears to be an appropriate operational unit for the conservation of genetic diversity, even for local breeds, for which varieties, if present, could also be taken into account.


Assuntos
Galinhas , Endogamia , Animais , Galinhas/genética , Feminino , Variação Genética , Masculino , Análise de Sequência com Séries de Oligonucleotídeos , Polimorfismo de Nucleotídeo Único , Densidade Demográfica
4.
Agron Sustain Dev ; 42(3): 53, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35702339

RESUMO

A profound transformation of agricultural production methods has become unavoidable due to the increase in the world's population, and environmental and climatic challenges. Agroecology is now recognized as a challenging model for agricultural systems, promoting their diversification and adaptation to environmental and socio-economic contexts, with consequences for the entire agri-food system and the development of rural and urban areas. Through a prospective exercise performed at a large interdisciplinary institute, INRAE, a research agenda for agroecology was built that filled a gap through its ambition and interdisciplinarity. It concerned six topics. For genetics, there is a need to study genetic aspects of complex systems (e.g., mixtures of genotypes) and to develop breeding methods for them. For landscapes, challenges lie in effects of heterogeneity at multiple scales, in multifunctionality and in the design of agroecological landscapes. Agricultural equipment and digital technologies show high potential for monitoring dynamics of agroecosystems. For modeling, challenges include approaches to complexity, consideration of spatial and temporal dimensions and representation of the cascade from cropping practices to ecosystem services. The agroecological transition of farms calls for modeling and observational approaches as well as for creating new design methods. Integration of agroecology into food systems raises the issues of product specificity, consumer behavior and organization of markets, standards and public policies. In addition, transversal priorities were identified: (i) generating sets of biological data, through research and participatory mechanisms, that are appropriate for designing agroecological systems and (ii) collecting and using coherent sets of data to enable assessment of vulnerability, resilience and risk in order to evaluate the performance of agroecological systems and to contribute to scaling up. The main lessons learned from this collective exercise can be useful for the entire scientific community engaged in research into agroecology.

5.
Front Genet ; 12: 666265, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34234809

RESUMO

In order to generate an atlas of the functional elements driving genome expression in domestic animals, the Functional Annotation of Animal Genome (FAANG) strategy was to sample many tissues from a few animals of different species, sexes, ages, and production stages. This article presents the collection of tissue samples for four species produced by two pilot projects, at INRAE (National Research Institute for Agriculture, Food and Environment) and the University of California, Davis. There were three mammals (cattle, goat, and pig) and one bird (chicken). It describes the metadata characterizing these reference sets (1) for animals with origin and selection history, physiological status, and environmental conditions; (2) for samples with collection site and tissue/cell processing; (3) for quality control; and (4) for storage and further distribution. Three sets are identified: set 1 comprises tissues for which collection can be standardized and for which representative aliquots can be easily distributed (liver, spleen, lung, heart, fat depot, skin, muscle, and peripheral blood mononuclear cells); set 2 comprises tissues requiring special protocols because of their cellular heterogeneity (brain, digestive tract, secretory organs, gonads and gametes, reproductive tract, immune tissues, cartilage); set 3 comprises specific cell preparations (immune cells, tracheal epithelial cells). Dedicated sampling protocols were established and uploaded in https://data.faang.org/protocol/samples. Specificities between mammals and chicken are described when relevant. A total of 73 different tissues or tissue sections were collected, and 21 are common to the four species. Having a common set of tissues will facilitate the transfer of knowledge within and between species and will contribute to decrease animal experimentation. Combining data on the same samples will facilitate data integration. Quality control was performed on some tissues with RNA extraction and RNA quality control. More than 5,000 samples have been stored with unique identifiers, and more than 4,000 were uploaded onto the Biosamples database, provided that standard ontologies were available to describe the sample. Many tissues have already been used to implement FAANG assays, with published results. All samples are available without restriction for further assays. The requesting procedure is described. Members of FAANG are encouraged to apply a range of molecular assays to characterize the functional status of collected samples and share their results, in line with the FAIR (Findable, Accessible, Interoperable, and Reusable) data principles.

6.
Front Genet ; 12: 655707, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34262593

RESUMO

In addition to their common usages to study gene expression, RNA-seq data accumulated over the last 10 years are a yet-unexploited resource of SNPs in numerous individuals from different populations. SNP detection by RNA-seq is particularly interesting for livestock species since whole genome sequencing is expensive and exome sequencing tools are unavailable. These SNPs detected in expressed regions can be used to characterize variants affecting protein functions, and to study cis-regulated genes by analyzing allele-specific expression (ASE) in the tissue of interest. However, gene expression can be highly variable, and filters for SNP detection using the popular GATK toolkit are not yet standardized, making SNP detection and genotype calling by RNA-seq a challenging endeavor. We compared SNP calling results using GATK suggested filters, on two chicken populations for which both RNA-seq and DNA-seq data were available for the same samples of the same tissue. We showed, in expressed regions, a RNA-seq precision of 91% (SNPs detected by RNA-seq and shared by DNA-seq) and we characterized the remaining 9% of SNPs. We then studied the genotype (GT) obtained by RNA-seq and the impact of two factors (GT call-rate and read number per GT) on the concordance of GT with DNA-seq; we proposed thresholds for them leading to a 95% concordance. Applying these thresholds to 767 multi-tissue RNA-seq of 382 birds of 11 chicken populations, we found 9.5 M SNPs in total, of which ∼550,000 SNPs per tissue and population with a reliable GT (call rate ≥ 50%) and among them, ∼340,000 with a MAF ≥ 10%. We showed that such RNA-seq data from one tissue can be used to (i) detect SNPs with a strong predicted impact on proteins, despite their scarcity in each population (16,307 SIFT deleterious missenses and 590 stop-gained), (ii) study, on a large scale, cis-regulations of gene expression, with ∼81% of protein-coding and 68% of long non-coding genes (TPM ≥ 1) that can be analyzed for ASE, and with ∼29% of them that were cis-regulated, and (iii) analyze population genetic using such SNPs located in expressed regions. This work shows that RNA-seq data can be used with good confidence to detect SNPs and associated GT within various populations and used them for different analyses as GTEx studies.

7.
Pigment Cell Melanoma Res ; 34(6): 1015-1028, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-33793042

RESUMO

Color patterns within individual feathers are common in birds but little is known about the genetic mechanisms causing such patterns. Here, we investigate the genetic basis for autosomal barring in chicken, a horizontal striping pattern on individual feathers. Using an informative backcross, we demonstrate that the MC1R locus is strongly associated with this phenotype. A deletion at SOX10, underlying the dark brown phenotype on its own, affects the manifestation of the barring pattern. The coding variant L133Q in MC1R is the most likely causal mutation for autosomal barring in this pedigree. Furthermore, a genetic screen across six different breeds showing different patterning phenotypes revealed that the most striking shared characteristics among these breeds were that they all carried the MC1R alleles Birchen or brown. Our data suggest that the presence of activating MC1R mutations enhancing pigment synthesis is an important mechanism underlying pigmentation patterns on individual feathers in chicken. We propose that MC1R and its antagonist ASIP play a critical role for determining within-feather pigmentation patterns in birds by acting as activator and inhibitor possibly in a Turing reaction-diffusion model.


Assuntos
Alelos , Proteínas Aviárias/genética , Galinhas/genética , Loci Gênicos , Pigmentação/genética , Receptor Tipo 1 de Melanocortina/genética , Animais , Proteínas Aviárias/metabolismo , Galinhas/metabolismo , Plumas/metabolismo , Genótipo , Receptor Tipo 1 de Melanocortina/metabolismo
8.
Data Brief ; 35: 106805, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33659583

RESUMO

Improvements in ex situ storage of genetic and reproductive materials offer an alternative for endangered livestock breed conservation. This paper presents a dataset for current ex situ collections and in situ population for 179 Spanish livestock breeds of seven species, cattle, sheep, pig, chicken, goat, horse and donkey. Ex situ data was obtained via survey administered to 18 functioning gene banks in Spain and relates to the reproductive genetic materials (semen doses) of 210 livestock breeds distributed across the gene banks. In situ data combines CENSUS information with linear regression techniques and relates to the geographic distribution of 179 Spanish autochthonous livestock breeds (2009-2018), and in situ population projections and extinction probabilities (2019-2060). We use a decision variable defining an "acceptable level of risk" that allows decision makers to specify tolerable levels of in situ breed endangerment when taking ex situ collection and storage decisions.

9.
Mol Phylogenet Evol ; 158: 107044, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33346111

RESUMO

The genus Gallus is distributed across a large part of Southeast Asia and has received special interest because the domestic chicken, Gallus gallus domesticus, has spread all over the world and is a major protein source for humans. There are four species: the red junglefowl (G. gallus), the green junglefowl (G. varius), the Lafayette's junglefowl (G. lafayettii) and the grey junglefowl (G. sonneratii). The aim of this study is to reconstruct the history of these species by a whole genome sequencing approach and resolve inconsistencies between well supported topologies inferred using different data and methods. Using deep sequencing, we identified over 35 million SNPs and reconstructed the phylogeny of the Gallus genus using both distance (BioNJ) and maximum likelihood (ML) methods. We observed discrepancies according to reconstruction methods and genomic components. The two most supported topologies were previously reported and were discriminated by using phylogenetic and gene flow analyses, based on ABBA statistics. Terminology fix requested by the deputy editor led to support a scenario with G. gallus as the earliest branching lineage of the Gallus genus, instead of G. varius. We discuss the probable causes for the discrepancy. A likely one is that G. sonneratii samples from parks or private collections are all recent hybrids, with roughly 10% of their autosomal genome originating from G. gallus. The removal of those regions is needed to provide reliable data, which was not done in previous studies. We took care of this and additionally included two wild G. sonneratii samples from India, showing no trace of introgression. This reinforces the importance of carefully selecting and validating samples and genomic components in phylogenomics.


Assuntos
Galinhas/genética , Genoma , Animais , Evolução Biológica , Galinhas/classificação , DNA/química , DNA/metabolismo , DNA Mitocondrial/classificação , DNA Mitocondrial/genética , Fluxo Gênico , Haplótipos , Funções Verossimilhança , Filogenia , Polimorfismo de Nucleotídeo Único , Análise de Componente Principal , Sequenciamento Completo do Genoma
10.
Biopreserv Biobank ; 18(3): 244-253, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32125896

RESUMO

The genetic diversity of livestock is decreasing and many countries have created gene banks for ex situ-in vitro conservation of animal genetic resources (AnGR). The collection, processing, and storage of animal germplasm require substantial investment and the material collected (and associated data) is highly valuable. Therefore, quality management systems (QMSs) and practices are important. The objective of this study was to review the quality management procedures of livestock gene banks around the world to identify the general strengths and weaknesses of quality control. A survey was administered by means of an online questionnaire consisting of 54 questions, most of which were yes/no with respect to the presence of a particular aspect of quality management. The survey was distributed through networks of the Food and Agriculture Organization of the United Nations that are associated with AnGR. Ninety responses were received from 62 countries. The gene banks were predominantly public institutions, with the main goal of preventing breed extinction. Approximately 30% of the banks reported having a QMS, 15 of which involved formal certification. Many other banks have plans to implement formal quality management within the next 5 years. Regarding specific aspects of quality management, more emphasis was placed on material entering the banks than on eventual utilization. Among the banks processing and freezing material, 90% followed specific standard operating procedures, but only 24% had policies regarding provision of access to external stakeholders. Increased cooperation among livestock gene banks could improve quality management. Sharing of knowledge could standardize procedures and cooperating peers could evaluate each other's QMSs.


Assuntos
Conservação dos Recursos Naturais/métodos , Variação Genética , Gado/crescimento & desenvolvimento , Animais , Cruzamento , Sistemas de Gerenciamento de Base de Dados , Gado/genética
11.
BMC Biol ; 17(1): 108, 2019 12 30.
Artigo em Inglês | MEDLINE | ID: mdl-31884969

RESUMO

BACKGROUND: Comparative genomics studies are central in identifying the coding and non-coding elements associated with complex traits, and the functional annotation of genomes is a critical step to decipher the genotype-to-phenotype relationships in livestock animals. As part of the Functional Annotation of Animal Genomes (FAANG) action, the FR-AgENCODE project aimed to create reference functional maps of domesticated animals by profiling the landscape of transcription (RNA-seq), chromatin accessibility (ATAC-seq) and conformation (Hi-C) in species representing ruminants (cattle, goat), monogastrics (pig) and birds (chicken), using three target samples related to metabolism (liver) and immunity (CD4+ and CD8+ T cells). RESULTS: RNA-seq assays considerably extended the available catalog of annotated transcripts and identified differentially expressed genes with unknown function, including new syntenic lncRNAs. ATAC-seq highlighted an enrichment for transcription factor binding sites in differentially accessible regions of the chromatin. Comparative analyses revealed a core set of conserved regulatory regions across species. Topologically associating domains (TADs) and epigenetic A/B compartments annotated from Hi-C data were consistent with RNA-seq and ATAC-seq data. Multi-species comparisons showed that conserved TAD boundaries had stronger insulation properties than species-specific ones and that the genomic distribution of orthologous genes in A/B compartments was significantly conserved across species. CONCLUSIONS: We report the first multi-species and multi-assay genome annotation results obtained by a FAANG project. Beyond the generation of reference annotations and the confirmation of previous findings on model animals, the integrative analysis of data from multiple assays and species sheds a new light on the multi-scale selective pressure shaping genome organization from birds to mammals. Overall, these results emphasize the value of FAANG for research on domesticated animals and reinforces the importance of future meta-analyses of the reference datasets being generated by this community on different species.


Assuntos
Animais Domésticos/genética , Cromatina/genética , Anotação de Sequência Molecular , Transcriptoma , Animais , Bovinos , Galinhas , Cabras , Filogenia , Sus scrofa
12.
Mol Ecol Resour ; 19(4): 997-1014, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30945415

RESUMO

The helmeted guinea fowl Numida meleagris belongs to the order Galliformes. Its natural range includes a large part of sub-Saharan Africa, from Senegal to Eritrea and from Chad to South Africa. Archaeozoological and artistic evidence suggest domestication of this species may have occurred about 2,000 years BP in Mali and Sudan primarily as a food resource, although villagers also benefit from its capacity to give loud alarm calls in case of danger, of its ability to consume parasites such as ticks and to hunt snakes, thus suggesting its domestication may have resulted from a commensal association process. Today, it is still farmed in Africa, mainly as a traditional village poultry, and is also bred more intensively in other countries, mainly France and Italy. The lack of available molecular genetic markers has limited the genetic studies conducted to date on guinea fowl. We present here a first-generation whole-genome sequence draft assembly used as a reference for a study by a Pool-seq approach of wild and domestic populations from Europe and Africa. We show that the domestic populations share a higher genetic similarity between each other than they do to wild populations living in the same geographical area. Several genomic regions showing selection signatures putatively related to domestication or importation to Europe were detected, containing candidate genes, most notably EDNRB2, possibly explaining losses in plumage coloration phenotypes in domesticated populations.


Assuntos
Domesticação , Evolução Molecular , Galliformes/classificação , Galliformes/genética , Genoma , Seleção Genética , África , Animais , Biologia Computacional , Europa (Continente) , Análise de Sequência de DNA , Sequenciamento Completo do Genoma
13.
Poult Sci ; 98(1): 447-455, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30165680

RESUMO

For the past 50 yr, practices for ex situ preservation of endangered breeds have been extended. Semen and primordial germ cells, gonadic tissues have been frozen to create genetic stocks of chicken genetic diversity in cryobanks. Semen cryopreservation stays the preferred method since it is not invasive. Many protocols have been developed to cryopreserve chicken semen, but they give highly variable success rate. The aim of the present study was to standardize and prove the effectiveness of semen long-term storage for the restitution of lost families. We showed that semen straws stored for 18 yr in liquid nitrogen did not lose their fertilizing ability. We demonstrated the usefulness of cryopreserved semen stored in the French National Cryobank for the recovery of families of a subfertile experimental chicken line. In order to highlight the standardization of the cryopreserved method, different cryoprotectant protocols were also tested on a rare breed, freezing/thawing and insemination conditions were controlled. The best results were obtained using glycerol protocol, a sperm dilution of 1:4 (semen:extender). The insemination dose of 200 million sperm/female was as efficient as 400 million of sperm. Altogether, these results demonstrated the effectiveness of chicken semen long-term storage for the restoration of lost genetic resources and highlighted the importance of standardized chicken semen cryopreservation using procedures combining biophysical (cryoprotectants, freezing/thawing conditions) and zootechnical (artificial insemination) features.


Assuntos
Galinhas/fisiologia , Criopreservação/veterinária , Preservação do Sêmen/veterinária , Espermatozoides/fisiologia , Animais , Galinhas/genética , Criopreservação/métodos , Crioprotetores/farmacologia , Feminino , Fertilidade/fisiologia , Congelamento , Variação Genética , Inseminação Artificial/métodos , Inseminação Artificial/veterinária , Masculino , Preservação do Sêmen/métodos , Bancos de Esperma/métodos
14.
Pigment Cell Melanoma Res ; 32(3): 381-390, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30457703

RESUMO

The chocolate plumage color in chickens is due to a sex-linked recessive mutation, choc, which dilutes eumelanin pigmentation. Because TYRP1 is sex-linked in chickens, and TYRP1 mutations determine brown coat color in mammals, TYRP1 appeared as the obvious candidate gene for the choc mutation. By combining gene mapping with gene capture, a complete association was identified between the chocolate phenotype and a missense mutation leading to a His214Asn change in the ZnA zinc-binding domain of the protein. A diagnostic test confirmed complete association by screening 428 non-chocolate chickens of various origins. This is the first TYRP1 mutation described in the chicken. Electron microscopy analysis showed that melanosomes were more numerous in feather follicles of chocolate chickens but exhibited an abnormal structure characterized by a granular content and an irregular shape. A similar altered morphology was observed on melanosomes of another TYRP1 mutant in birds, the roux mutation of the quail.


Assuntos
Cor de Cabelo/genética , Melanossomas/patologia , Mutação de Sentido Incorreto , Oxirredutases/genética , Transtornos da Pigmentação/patologia , Pigmentação/genética , Animais , Sequência de Bases , Galinhas , Feminino , Masculino , Melanossomas/genética , Fenótipo , Transtornos da Pigmentação/genética , Homologia de Sequência
16.
Front Genet ; 9: 251, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30057590

RESUMO

Using genomic information, local ruminant populations can be better characterized and compared to selected ones. Genetic relationships between animals can be established even without systematic pedigree recording, provided a budget is available for genotyping. Genomic selection (GS) can rely on a subset of the total population and does not require a costly national infrastructure, e.g., based on progeny testing. Yet, the use of genomic tools for animal breeding in developing countries is still limited. We identify three main reasons for this: (i) the instruments for cheap recording of phenotypes and data management are still limiting. (ii) many developing countries are recurrently exposed to unfavorable conditions (heat, diseases, poor nutrition) requiring special attention to fitness traits, (iii) a high level of expertise in quantitative genetics, modeling, and data manipulation is needed to perform genomic analyses. Yet, the potential outcomes go much beyond genetic improvements and can improve the resilience of the whole farming system. They include a better management of genetic diversity of local populations, a more balanced genetic progress and the possibility to unravel the genetic basis of adaptation of local breeds through whole genome approaches. A GS program being developed by BAIF, a large Indian NGO, is analyzed as a pilot case. It relies on the creation of a female reference population of Bos indicus and crossbreds, recorded with modern technology (e.g., smartphones) to collect performances at low cost in tiny herds on production and fertility. Finally, recommendations for the implementation of GS in developing countries are proposed.

18.
PLoS Genet ; 13(4): e1006665, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28388616

RESUMO

Sex-linked barring is a fascinating plumage pattern in chickens recently shown to be associated with two non-coding and two missense mutations affecting the ARF transcript at the CDKN2A tumor suppressor locus. It however remained a mystery whether all four mutations are indeed causative and how they contribute to the barring phenotype. Here, we show that Sex-linked barring is genetically heterogeneous, and that the mutations form three functionally different variant alleles. The B0 allele carries only the two non-coding changes and is associated with the most dilute barring pattern, whereas the B1 and B2 alleles carry both the two non-coding changes and one each of the two missense mutations causing the Sex-linked barring and Sex-linked dilution phenotypes, respectively. The data are consistent with evolution of alleles where the non-coding changes occurred first followed by the two missense mutations that resulted in a phenotype more appealing to humans. We show that one or both of the non-coding changes are cis-regulatory mutations causing a higher CDKN2A expression, whereas the missense mutations reduce the ability of ARF to interact with MDM2. Caspase assays for all genotypes revealed no apoptotic events and our results are consistent with a recent study indicating that the loss of melanocyte progenitors in Sex-linked barring in chicken is caused by premature differentiation and not apoptosis. Our results show that CDKN2A is a major locus driving the differentiation of avian melanocytes in a temporal and spatial manner.


Assuntos
Inibidor p16 de Quinase Dependente de Ciclina/genética , Evolução Molecular , Ligação Genética , Pigmentação/genética , Alelos , Animais , Diferenciação Celular/genética , Galinhas , Plumas/crescimento & desenvolvimento , Plumas/metabolismo , Feminino , Genótipo , Mutação , Fenótipo
19.
Genet Sel Evol ; 49(1): 39, 2017 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-28427323

RESUMO

BACKGROUND: Growth traits can be used as indicators of adaptation to sub-optimal conditions. The current study aimed at identifying quantitative trait loci (QTL) that control performance under variable temperature conditions in chickens. METHODS: An F2 population was produced by crossing the Taiwan Country chicken L2 line (selected for body weight, comb area, and egg production) with an experimental line of Rhode Island Red layer R- (selected for low residual feed consumption). A total of 844 animals were genotyped with the 60 K Illumina single nucleotide polymorphism (SNP) chip. Whole-genome interval linkage mapping and a genome-wide association study (GWAS) were performed for body weight at 0, 4, 8, 12, and 16 weeks of age, shank length at 8 weeks of age, size of comb area at 16 weeks of age, and antibody response to sheep red blood cells at 11 weeks of age (7 and 14 days after primary immunization). Relevant genes were identified based on functional annotation of candidate genes and potentially relevant SNPs were detected by comparing whole-genome sequences of several birds between the parental lines. RESULTS: Whole-genome QTL analysis revealed 47 QTL and 714 effects associated with 178 SNPs were identified by GWAS with 5% Bonferroni genome-wide significance. Little overlap was observed between the QTL and GWAS results, with only two chromosomal regions detected by both approaches, i.e. one on GGA24 (GGA for Gallus gallus chromosome) for BW04 and one on GGAZ for six growth-related traits. Based on whole-genome sequence, differences between the parental lines based on several birds were screened in the genome-wide QTL regions and in a region detected by both methods, resulting in the identification of 106 putative candidate genes with a total of 15,443 SNPs, of which 41 were missense and 1698 were not described in the dbSNP archive. CONCLUSIONS: The QTL detected in this study for growth and morphological traits likely influence adaptation of chickens to sub-tropical climate. Using whole-genome sequence data, we identified candidate SNPs for further confirmation of QTL in the F2 design. A strong QTL effect found on GGAZ underlines the importance of sex-linked inheritance for growth traits in chickens.


Assuntos
Aclimatação/genética , Galinhas/genética , Locos de Características Quantitativas , Animais , Feminino , Masculino , Polimorfismo de Nucleotídeo Único
20.
Front Genet ; 6: 314, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26539210

RESUMO

Livestock conservation practice is changing rapidly in light of policy developments, climate change and diversifying market demands. The last decade has seen a step change in technology and analytical approaches available to define, manage and conserve Farm Animal Genomic Resources (FAnGR). However, these rapid changes pose challenges for FAnGR conservation in terms of technological continuity, analytical capacity and integrative methodologies needed to fully exploit new, multidimensional data. The final conference of the ESF Genomic Resources program aimed to address these interdisciplinary problems in an attempt to contribute to the agenda for research and policy development directions during the coming decade. By 2020, according to the Convention on Biodiversity's Aichi Target 13, signatories should ensure that "…the genetic diversity of …farmed and domesticated animals and of wild relatives …is maintained, and strategies have been developed and implemented for minimizing genetic erosion and safeguarding their genetic diversity." However, the real extent of genetic erosion is very difficult to measure using current data. Therefore, this challenging target demands better coverage, understanding and utilization of genomic and environmental data, the development of optimized ways to integrate these data with social and other sciences and policy analysis to enable more flexible, evidence-based models to underpin FAnGR conservation. At the conference, we attempted to identify the most important problems for effective livestock genomic resource conservation during the next decade. Twenty priority questions were identified that could be broadly categorized into challenges related to methodology, analytical approaches, data management and conservation. It should be acknowledged here that while the focus of our meeting was predominantly around genetics, genomics and animal science, many of the practical challenges facing conservation of genomic resources are societal in origin and are predicated on the value (e.g., socio-economic and cultural) of these resources to farmers, rural communities and society as a whole. The overall conclusion is that despite the fact that the livestock sector has been relatively well-organized in the application of genetic methodologies to date, there is still a large gap between the current state-of-the-art in the use of tools to characterize genomic resources and its application to many non-commercial and local breeds, hampering the consistent utilization of genetic and genomic data as indicators of genetic erosion and diversity. The livestock genomic sector therefore needs to make a concerted effort in the coming decade to enable to the democratization of the powerful tools that are now at its disposal, and to ensure that they are applied in the context of breed conservation as well as development.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA