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1.
Nat Genet ; 51(11): 1637-1644, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31676860

RESUMO

Volumetric variations of the human brain are heritable and are associated with many brain-related complex traits. Here we performed genome-wide association studies (GWAS) of 101 brain volumetric phenotypes using the UK Biobank sample including 19,629 participants. GWAS identified 365 independent genetic variants exceeding a significance threshold of 4.9 × 10-10, adjusted for testing multiple phenotypes. A gene-based association study found 157 associated genes (124 new), and functional gene mapping analysis linked 146 additional genes. Many of the discovered genetic variants and genes have previously been implicated in cognitive and mental health traits. Through genome-wide polygenic-risk-score prediction, more than 6% of the phenotypic variance (P = 3.13 × 10-24) in four other independent studies could be explained by the UK Biobank GWAS results. In conclusion, our study identifies many new genetic associations at the variant, locus and gene levels and advances our understanding of the pleiotropy and genetic co-architecture between brain volumes and other traits.


Assuntos
Encéfalo/anatomia & histologia , Transtornos Cognitivos/genética , Marcadores Genéticos , Estudo de Associação Genômica Ampla , Transtornos Mentais/genética , Polimorfismo de Nucleotídeo Único , Característica Quantitativa Herdável , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Encéfalo/metabolismo , Criança , Pré-Escolar , Transtornos Cognitivos/patologia , Estudos de Coortes , Feminino , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Desequilíbrio de Ligação , Masculino , Transtornos Mentais/patologia , Saúde Mental , Pessoa de Meia-Idade , Herança Multifatorial , Fenótipo , Reino Unido , Adulto Jovem
2.
Yi Chuan ; 41(11): 1023-1040, 2019 Nov 20.
Artigo em Chinês | MEDLINE | ID: mdl-31735705

RESUMO

Heritability, one of the central quantitative genetic parameters, is critically important to measure the genetic variation of traits, especially in the studies of the response to selection in evolutionary biology and agriculture, and the prediction of disease risks in medicine. The statistical model and method for estimating heritability have been continually developed and improved, since the genetic variance components was first proposed by Fisher in 1918. Recently, the term "microbiability" (m 2), an analogous concept and estimated method to heritability, was introduced in gut microbiome research for evaluating the effect of entire microbiota on a host phenotype. In this review, we summarize the progress of statistical methods in the heritability estimation, as well as the current state of gut microbiome associations with the host genome, with a particular focus on the concept and estimated methods of microbiability. Our review will provide a reference for the future study of host phenotypic variation that can be inferred by the gut microbiota.


Assuntos
Evolução Biológica , Modelos Genéticos , Característica Quantitativa Herdável , Microbioma Gastrointestinal , Genoma , Fenótipo
3.
J Anim Sci ; 97(10): 4053-4065, 2019 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-31581299

RESUMO

Selection for production traits with little or no emphasis on health-related traits has the potential to increase susceptibility to disease in food-producing animals. A possible genetic strategy to mitigate such effects is to include both production and health traits in the breeding objective when selecting animals. For this to occur, reliable methodologies are required to assess beneficial health traits, such as the immune capacity of animals. We describe here a methodology to assess the immune competence of beef cattle which is both practical to apply on farm and does not restrict the future sale of tested animals. The methodology also accommodates variation in prior vaccination history of cohorts of animals being tested. In the present study, the immune competence phenotype of 1,100 Angus calves was assessed during yard weaning. Genetic parameters associated with immune competence traits were estimated and associations between immune competence, temperament, and stress-coping ability traits were investigated. Results suggested that immune competence traits, related to an animal's ability to mount both antibody and cell-mediated immune responses, are moderately heritable (h2 = 0.32 ± 0.09 and 0.27 ± 0.08, respectively) and favorably genetically correlated with the temperament trait, flight time (r = 0.63 ± 0.31 and 0.60 ± 0.29 with antibody and cell-mediated immune responses, respectively). Development of methodologies to assess the immune competence phenotype of beef cattle is a critical first step in the establishment of genetic selection strategies aimed at improving the general disease resistance of beef herds. Strategies aimed at reducing the incidence of disease in beef cattle are expected to significantly improve animal health and welfare, reduce reliance on the use of antibiotics to treat disease, and reduce disease-associated costs incurred by producers.


Assuntos
Bovinos/genética , Bovinos/imunologia , Característica Quantitativa Herdável , Estresse Fisiológico/imunologia , Temperamento/fisiologia , Desmame , Animais , Cruzamento , Bovinos/fisiologia , Estudos de Coortes , Feminino , Masculino , Fenótipo , Seleção Genética
4.
Nat Genet ; 51(10): 1549-1558, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31570895

RESUMO

Domestication of clonally propagated crops such as pineapple from South America was hypothesized to be a 'one-step operation'. We sequenced the genome of Ananas comosus var. bracteatus CB5 and assembled 513 Mb into 25 chromosomes with 29,412 genes. Comparison of the genomes of CB5, F153 and MD2 elucidated the genomic basis of fiber production, color formation, sugar accumulation and fruit maturation. We also resequenced 89 Ananas genomes. Cultivars 'Smooth Cayenne' and 'Queen' exhibited ancient and recent admixture, while 'Singapore Spanish' supported a one-step operation of domestication. We identified 25 selective sweeps, including a strong sweep containing a pair of tandemly duplicated bromelain inhibitors. Four candidate genes for self-incompatibility were linked in F153, but were not functional in self-compatible CB5. Our findings support the coexistence of sexual recombination and a one-step operation in the domestication of clonally propagated crops. This work guides the exploration of sexual and asexual domestication trajectories in other clonally propagated crops.


Assuntos
Ananas/genética , Produtos Agrícolas/genética , Domesticação , Genoma de Planta , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética , Característica Quantitativa Herdável , Ananas/crescimento & desenvolvimento , Bromelaínas/metabolismo , Produtos Agrícolas/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas , Fenótipo , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Dinâmica Populacional , Açúcares/metabolismo
5.
BMC Evol Biol ; 19(1): 185, 2019 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-31604422

RESUMO

BACKGROUND: Studying reproductive trait allometries can help to understand optimal male investment strategies under sexual selection. In promiscuous mating systems, studies across several taxa suggest that testes allometry is usually positive, presumably due to strong selection on sperm numbers through intense sperm competition. Here, we investigated testes allometry in a bush-cricket species, Metaplastes ornatus, in which females mate promiscuously, but where sperm removal behaviour by males likely drastically reduces realised sperm competition level. RESULTS: As hypothesised, we found evidence for negative testes allometry and hence a fundamentally different male investment strategy compared to species under intense sperm competition. In addition, the mean relative testes size of M. ornatus was small compared to other species of bush-crickets. Surprisingly, the spermatophore gland, a potential alternative trait that males could invest in instead of testes, also did not show positive allometry, but was approximately isometric. We further observed the expected pattern of negative allometry for the male morphological structure responsible for sperm removal in this species, the subgenital plate, supporting the one-size-fits-all hypothesis for intromittent genitalia. CONCLUSION: Our findings suggest that the evolution of sperm removal behaviour in M. ornatus was a key adaptation for avoiding sperm competition, with important consequences for reproductive trait allometries. Nevertheless, they also imply that it does not pay for larger males to invest disproportionately in nuptial gift production in this species.


Assuntos
Gryllidae/anatomia & histologia , Gryllidae/fisiologia , Característica Quantitativa Herdável , Espermatozoides/fisiologia , Animais , Feminino , Masculino , Tamanho do Órgão , Fenótipo , Análise de Regressão , Reprodução , Testículo/anatomia & histologia
6.
Theor Appl Genet ; 132(12): 3375-3398, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31555887

RESUMO

KEY MESSAGE: This study demonstrates that an active breeding nursery with rotation can be used to identify marker-trait associations for biomass yield and quality parameters that are important for biorefinery purposes. Wheat straw is a valuable feedstock for bioethanol production, but due to the recalcitrant nature of lignocellulose, its efficient use in biorefineries is limited by its low digestibility and difficult conversion of structural carbohydrates into free sugars. A genome-wide association study (GWAS) was conducted to search for significant SNP markers that could be used in a breeding programme to improve the value of wheat straw in a biorefinery setting. As part of a 3-year breeding programme (2013-2016), 190 winter wheat lines were phenotyped for traits that affect the yield and quality of the harvested biomass. These traits included straw yield, plant height, lodging at three growth stages and Septoria tritici blotch (STB) susceptibility. Release of glucose, xylose and arabinose was determined after hydrothermal pretreatment and enzymatic hydrolysis of the straw. The lines were genotyped using 15 K SNP markers and 5552 SNP markers could be used after filtering. Heritability for all traits ranged from 0.02 to 0.74. GWASs were conducted using CMLM, SUPER and FarmCPU algorithms, to analyse which algorithm could detect the highest number of marker-trait associations (MTAs). Comparable tendencies were obtained from CMLM and FarmCPU, but FarmCPU produced the most significant results. MTAs were obtained for lodging, harvest index, plant height, STB, glucose, xylose and arabinose at a significance level of p < 9.01 × 10-6. MTAs in chromosome 6A were observed for glucose, xylose and arabinose, and could be of importance for increasing sugar release for bioethanol production.


Assuntos
Melhoramento Vegetal , Característica Quantitativa Herdável , Triticum/crescimento & desenvolvimento , Triticum/genética , Biomassa , Estudos de Associação Genética , Marcadores Genéticos , Genótipo , Fenótipo , Polimorfismo de Nucleotídeo Único
7.
Int J Mol Sci ; 20(18)2019 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-31505900

RESUMO

Seed storability, defined as the ability to remain alive during storage, is an important agronomic and physiological characteristic, but the underlying genetic mechanism remains largely unclear. Here, we report quantitative trait loci (QTLs) analyses for seed storability using a high-density single nucleotide polymorphism linkage map in the backcross recombinant inbred lines that was derived from a cross of a japonica cultivar, Nipponbare, and an indica cultivar, 9311. Seven putative QTLs were identified for seed storability under natural storage, each explaining 3.6-9.0% of the phenotypic variation in this population. Among these QTLs, qSS1 with the 9311 alleles promoting seed storability was further validated in near-isogenic line and its derived-F2 population. The other locus (qSS3.1) for seed storability colocalized with a locus for germination ability under hydrogen peroxide, which is recognized as an oxidant molecule that causes lipid damage. Transgenic experiments validated that a candidate gene (OsFAH2) resides the qSS3.1 region controlling seed storability and antioxidant capability. Overexpression of OsFAH2 that encodes a fatty acid hydroxylase reduced lipid preoxidation and increased seed storability. These findings provide new insights into the genetic and physiological bases of seed storability and will be useful for the improvement of seed storability in rice.


Assuntos
Antioxidantes , Genes de Plantas , Oryza/genética , Característica Quantitativa Herdável , Sementes/genética , Peroxidação de Lipídeos/genética , Oxigenases de Função Mista/genética , Oxigenases de Função Mista/metabolismo , Oryza/metabolismo , Polimorfismo de Nucleotídeo Único , Sementes/metabolismo
8.
Nat Commun ; 10(1): 4097, 2019 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-31506438

RESUMO

Phenotypic variation of quantitative traits is orchestrated by a complex interplay between the environment (e.g. diet) and genetics. However, the impact of gene-environment interactions on phenotypic traits mostly remains elusive. To address this, we feed 1154 mice of an autoimmunity-prone intercross line (AIL) three different diets. We find that diet substantially contributes to the variability of complex traits and unmasks additional genetic susceptibility quantitative trait loci (QTL). By performing whole-genome sequencing of the AIL founder strains, we resolve these QTLs to few or single candidate genes. To address whether diet can also modulate genetic predisposition towards a given trait, we set NZM2410/J mice on similar dietary regimens as AIL mice. Our data suggest that diet modifies genetic susceptibility to lupus and shifts intestinal bacterial and fungal community composition, which precedes clinical disease manifestation. Collectively, our study underlines the importance of including environmental factors in genetic association studies.


Assuntos
Cruzamentos Genéticos , Dieta , Genes , Estudos de Associação Genética , Característica Quantitativa Herdável , Animais , Animais não Endogâmicos , Anticorpos Antinucleares/genética , Bactérias/crescimento & desenvolvimento , Biodiversidade , Feminino , Fungos/crescimento & desenvolvimento , Predisposição Genética para Doença , Nefrite Lúpica/genética , Nefrite Lúpica/imunologia , Masculino , Camundongos , Microbiota , Mapeamento Físico do Cromossomo , Locos de Características Quantitativas/genética , Baço/metabolismo , Transcriptoma/genética , Sequenciamento Completo do Genoma
9.
BMC Evol Biol ; 19(1): 179, 2019 09 12.
Artigo em Inglês | MEDLINE | ID: mdl-31510915

RESUMO

BACKGROUND: Understanding the mechanisms promoting or constraining morphological diversification within clades is a central topic in evolutionary biology. Ecological transitions are of particular interest because of their influence upon the selective forces and factors involved in phenotypic evolution. Here we focused on the humerus and mandibles of talpid moles to test whether the transition to the subterranean lifestyle impacted morphological disparity and phenotypic traits covariation between these two structures. RESULTS: Our results indicate non-subterranean species occupy a significantly larger portion of the talpid moles morphospace. However, there is no difference between subterranean and non-subterranean moles in terms of the strength and direction of phenotypic integration. CONCLUSIONS: Our study shows that the transition to a subterranean lifestyle significantly reduced morphological variability in talpid moles. However, this reduced disparity was not accompanied by changes in the pattern of traits covariation between the humerus and the mandible, suggesting the presence of strong phylogenetic conservatism within this pattern.


Assuntos
Ecossistema , Toupeiras/anatomia & histologia , Pontos de Referência Anatômicos , Animais , Úmero/anatomia & histologia , Análise dos Mínimos Quadrados , Estilo de Vida , Mandíbula/anatomia & histologia , Toupeiras/classificação , Fenótipo , Filogenia , Análise de Componente Principal , Característica Quantitativa Herdável
10.
Anim Genet ; 50(6): 634-643, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31502261

RESUMO

Genomic prediction has been widely utilized to estimate genomic breeding values (GEBVs) in farm animals. In this study, we conducted genomic prediction for 20 economically important traits including growth, carcass and meat quality traits in Chinese Simmental beef cattle. Five approaches (GBLUP, BayesA, BayesB, BayesCπ and BayesR) were used to estimate the genomic breeding values. The predictive accuracies ranged from 0.159 (lean meat percentage estimated by BayesCπ) to 0.518 (striploin weight estimated by BayesR). Moreover, we found that the average predictive accuracies across 20 traits were 0.361, 0.361, 0.367, 0.367 and 0.378, and the averaged regression coefficients were 0.89, 0.86, 0.89, 0.94 and 0.95 for GBLUP, BayesA, BayesB, BayesCπ and BayesR respectively. The genomic prediction accuracies were mostly moderate and high for growth and carcass traits, whereas meat quality traits showed relatively low accuracies. We concluded that Bayesian regression approaches, especially for BayesR and BayesCπ, were slightly superior to GBLUP for most traits. Increasing with the sizes of reference population, these two approaches are feasible for future application of genomic selection in Chinese beef cattle.


Assuntos
Bovinos/crescimento & desenvolvimento , Bovinos/genética , Animais , Teorema de Bayes , Cruzamento , Bovinos/classificação , Carne , Característica Quantitativa Herdável
11.
Genes (Basel) ; 10(8)2019 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-31409015

RESUMO

Potassium (K) is one of the most important mineral nutrients for wheat. In this study, the effects of low K (LK) treatments and the quantitative trait loci (QTLs) for K, calcium (Ca), and magnesium (Mg) use efficiency traits, both at the seedling and maturity stages of wheat, were investigated. The set of "Tainong 18 × Linmai 6" recombinant inbred lines (RILs) were used to identify the QTLs under different K treatments using hydroponic culture and field trials. The majority of K concentrations and content-related traits at seedling and maturity stages decreased with reduced K supply, but the K use efficiency-related traits increased. In contrast, with reduced K supply, the contents of Ca and Mg increased, while the Ca and Mg use efficiency decreased. A total of 217 QTLs for seedling traits and 89 QTLs for adult traits were detected. Four relatively high-frequency QTLs (RHF-QTLs) and 18 QTL clusters (colocation of QTLs for more than two traits) were detected. Eight clusters were detected for K-, Ca-, and Mg-related traits simultaneously. This means that these traits might be controlled by the same QTL. In addition, we highlight that 4B might be an important chromosome regulating the nutrition of K, Ca, and Mg in wheat. The 4B chromosome and four hot QTL clusters, which located 45 QTLs, might be important potential targets for further investigation.


Assuntos
Cálcio/metabolismo , Magnésio/metabolismo , Potássio/metabolismo , Locos de Características Quantitativas , Triticum/genética , Característica Quantitativa Herdável , Plântula/genética , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Triticum/crescimento & desenvolvimento , Triticum/metabolismo
12.
An Acad Bras Cienc ; 91(3): e20180387, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31432899

RESUMO

This study aimed to estimate genetic parameters and correlations between morphological, agronomic and root quality traits of cassava plants, as well as to study cause and effect relationships through path analysis. A total of 814 genotypes were evaluated from 2011 to 2015. The joint analysis of the data was performed by the mixed models approach. The predicted genetic values of the genotypes were used to estimate the genetic correlations among as well the path analysis. The estimates of heritability of the genotype means ranged from 0.31 (commercial fresh root yield - CRY) to 0.62 (plant height - PLH). The highest genetic correlation coefficient estimates were observed for starch yield (STY) × total fresh root yield (FRY) (0.97). The results of the path analysis showed that FRY had the highest direct effect on STY, but the indirect selection based on FRY was not efficient to improve the gain of STY.


Assuntos
Variação Genética/genética , Manihot/genética , Característica Quantitativa Herdável , Seleção Genética/genética , Genótipo
13.
Int J Mol Sci ; 20(17)2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31466256

RESUMO

One of the most chronic constraints to crop production is the grain yield reduction near the crop harvest stage by lodging worldwide. This is more prevalent in cereal crops, particularly in wheat and rice. Major factors associated with lodging involve morphological and anatomical traits along with the chemical composition of the stem. These traits have built up the remarkable relationship in wheat and rice genotypes either prone to lodging or displaying lodging resistance. In this review, we have made a comparison of our conceptual perceptions with foregoing published reports and proposed the fundamental controlling techniques that could be practiced to control the devastating effects of lodging stress. The management of lodging stress is, however, reliant on chemical, agronomical, and genetic factors that are reducing the risk of lodging threat in wheat and rice. But, still, there are many questions remain to be answered to elucidate the complex lodging phenomenon, so agronomists, breeders, physiologists, and molecular biologists require further investigation to address this challenging problem.


Assuntos
Oryza/genética , Melhoramento Vegetal/métodos , Estresse Fisiológico , Triticum/genética , Oryza/fisiologia , Característica Quantitativa Herdável , Triticum/fisiologia
14.
Genome Med ; 11(1): 57, 2019 08 29.
Artigo em Inglês | MEDLINE | ID: mdl-31466529

RESUMO

Insomnia is a common condition whose pathophysiology is poorly understood. Large genetic studies have provided insights into the etiology of insomnia, highlighting biological pathways that are shared with other complex disorders. Increased focus on treating sleep problems in the clinic and through public health interventions may reduce the overall burden of disease in human populations.


Assuntos
Suscetibilidade a Doenças , Herança Multifatorial , Distúrbios do Início e da Manutenção do Sono/etiologia , Estudos de Associação Genética , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Característica Quantitativa Herdável , Distúrbios do Início e da Manutenção do Sono/epidemiologia
15.
Genes (Basel) ; 10(8)2019 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-31416156

RESUMO

The SPP1, LAP3, and LCORL are located on chromosome 6 of sheep and a domain of 36.15-38.56 Mb, which plays an essential role in tissue and embryonic growth. In this study, we cloned the complete coding sequences of SPP1 and partial coding regions of LAP3 and LCORL from Hu sheep (Gansu Province, China) and analyzed their genomic structures. The RT-qPCR showed that the three genes were expressed widely in the different tissues of Hu sheep. The SPP1 expression was significantly higher in the kidney (p < 0.01) and LAP3 expression was significantly higher in the spleen, lung, kidney, and duodenum than in the other tissues (heart, liver, rumen, muscle, fat, and ovary; p < 0.05). The LCORL was preferentially expressed in the spleen, duodenum, and lung (p < 0.05). In addition, the nucleotide substitution NM_001009224.1:c.132A>C was found in SPP1; an association analysis showed that it was associated with birth weight and yearling weight (p < 0.05), and NM_001009224.1:c.132C was the dominant allele. Two mutations XM_012179698.3:c.232C>G and XM_012179698.3:c.1154C>T were identified in LAP3. The nucleotide substitution XM_012179698.3:c.232C>G was confirmed to be associated with birth weight, 1-month weight, 3-month weight (p < 0.05), and 2-month weight (p < 0.01). The nucleotide substitution XM_012179698.3:c.1154C>T was associated with birth weight (p < 0.01), 1-month weight, and 2-month weight (p < 0.05). The LAP3 gene XM_012179698.3:c.232C>G mutation with the C allele has higher body weight than other sheep, and CC genotype individuals show higher birth weight, 1-month weight, and weaning weight than the GG genotype individuals (p < 0.05). Our results support the conclusion that the mutations on ovine SPP1 and LAP3 successfully track functional alleles that affect growth in sheep, and these genes could be used as candidate genes for improving the growth traits of sheep during breeding.


Assuntos
Peso Corporal/genética , Leucil Aminopeptidase/genética , Osteopontina/genética , Característica Quantitativa Herdável , Proteínas Repressoras/genética , Ovinos/genética , Animais , Leucil Aminopeptidase/metabolismo , Osteopontina/metabolismo , Locos de Características Quantitativas , Proteínas Repressoras/metabolismo , Ovinos/crescimento & desenvolvimento
16.
Genes (Basel) ; 10(8)2019 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-31366144

RESUMO

The identification of biological mechanisms underlying the development of complex quantitative traits, including those that contribute to plant architecture, yield and quality potential, and seed dispersal, is a major focus in the evolutionary biology and plant breeding. The awn, a bristle-like extension from the lemma in the floret, is one of the distinct morphological and physiological traits in grass species. Awns are taught as an evolutionary trait assisting seed dispersal and germination and increasing photosynthesis. Awn development seems to be complex process, involving dramatic phenotypic and molecular changes. Although recent advances investigated the underlying morphological and molecular genetic factors of awn development, there is little agreement about how these factors interact during awn formation and how this interaction affects variation of awn morphology. Consequently, the developmental sequence of the awn is not yet well understood. Here, we review awn morphological and histological features, awn development pathways, and molecular processes of awn development. We argue that morphological and molecular genetic mechanisms of awn development previously studied in major cereal crops, such as barley, wheat, and rice, offered intriguing insights helping to characterize this process in a comparative approach. Applying such an approach will aid to deeply understand factors involved in awn development in grass species.


Assuntos
Flores/anatomia & histologia , Poaceae/genética , Característica Quantitativa Herdável , Flores/genética , Flores/crescimento & desenvolvimento , Desenvolvimento Vegetal , Poaceae/anatomia & histologia , Poaceae/crescimento & desenvolvimento
17.
BMC Res Notes ; 12(1): 456, 2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31340859

RESUMO

OBJECTIVE: Hybrid zones are geographic regions where genetically distinct taxa interbreed, resulting in offspring of mixed ancestry. California Scrub-Jays (Aphelocoma californica) and Woodhouse's Scrub-Jays (A. woodhouseii) come into secondary contact and hybridize in western Nevada. Although previous work investigated divergence and gene flow between these species using a handful of microsatellite markers, the hybrid zone has not been studied using genome-scale markers, providing an opportunity to assess genome-wide introgression, test for a genetic basis for ecomorphological traits, and compare these estimates to those derived from microsatellites. RESULTS: Using variant sites flanking ultraconserved elements (UCEs), we performed population assignment and quantified hybrid ancestry for 16 individuals across the zone of secondary contact. Our study included 2468 SNPs distributed throughout the genome, allowing discrimination of genetic affinities of hybrid individuals that were similar to estimates from microsatellites. We show a relationship between bill and wing length and the genetic composition of individuals that was not found in prior work using microsatellites, suggesting a genetic basis for these traits. Our analyses demonstrate the utility of UCEs for the analysis of hybrid zones and provide a basis for future studies to identify the genomic architecture of speciation and phenotypic differences between these incipient species.


Assuntos
Sondas de DNA , Genoma , Hibridização Genética , Passeriformes/genética , Característica Quantitativa Herdável , Animais , Bico/anatomia & histologia , Bico/metabolismo , Cruzamentos Genéticos , Feminino , Fluxo Gênico , Especiação Genética , Genética Populacional , Masculino , Repetições de Microssatélites , Passeriformes/classificação , Fenótipo , Polimorfismo de Nucleotídeo Único , Análise de Sequência de DNA , Asas de Animais/anatomia & histologia , Asas de Animais/metabolismo
18.
Int J Mol Sci ; 20(14)2019 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-31330985

RESUMO

Smith-Magenis syndrome (SMS), linked to Retinoic Acid Induced (RAI1) haploinsufficiency, is a unique model of the inversion of circadian melatonin secretion. In this regard, this model is a formidable approach to better understand circadian melatonin secretion cycle disorders and the role of the RAI1 gene in this cycle. Sleep-wake cycle disorders in SMS include sleep maintenance disorders with a phase advance and intense sleepiness around noon. These disorders have been linked to a general disturbance of sleep-wake rhythm and coexist with inverted secretion of melatonin. The exact mechanism underlying the inversion of circadian melatonin secretion in SMS has rarely been discussed. We suggest three hypotheses that could account for the inversion of circadian melatonin secretion and discuss them. First, inversion of the circadian melatonin secretion rhythm could be linked to alterations in light signal transduction. Second, this inversion could imply global misalignment of the circadian system. Third, the inversion is not linked to a global circadian clock shift but rather to a specific impairment in the melatonin secretion pathway between the suprachiasmatic nuclei (SCN) and pinealocytes. The development of diurnal SMS animal models that produce melatonin appears to be an indispensable step to further understand the molecular basis of the circadian melatonin secretion rhythm.


Assuntos
Suscetibilidade a Doenças , Melatonina/biossíntese , Síndrome de Smith-Magenis/etiologia , Síndrome de Smith-Magenis/metabolismo , Animais , Mapeamento Cromossômico , Ritmo Circadiano , Predisposição Genética para Doença , Humanos , Locos de Características Quantitativas , Característica Quantitativa Herdável , Síndrome de Smith-Magenis/diagnóstico
19.
J Dairy Sci ; 102(9): 8221-8233, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31279559

RESUMO

The number of dairy cows milked in automatic milking systems (AMS) is steadily increasing in Norway. Capacity and efficiency of AMS are highly dependent on the individual cow's milking efficiency, such as milking speed and occupation time in the milking robot. Cows meet new challenges in herds utilizing AMS. Consequently, new or revised traits may be needed for genetic evaluation of dairy cattle. The AMS records relevant information on an individual cow basis. The aims of this study were to estimate genetic parameters of new automatically recorded milkability and temperament traits. Data from 77 commercial herds with Norwegian Red dairy cattle were analyzed by mixed linear animal models. The final data set contained 1,012,912 daily records from 4,883 cows in first to ninth lactation. For variance component estimation, univariate and bivariate models were used. Daily records of box time (BT), average flow rate (FR), kilograms of milk per minute of box time (MEF), handling time (HT), log-transformed HT, milking frequency, and milking interval were analyzed with repeatability models. Among these traits, FR, BT, and MEF showed the highest heritabilities of 0.48, 0.27, and 0.22, respectively, whereas heritability of log-transformed HT, HT, milking frequency, and milking interval was low (0.02-0.07). Unsuccessful milkings expressed as rejected milkings, incomplete milkings (IM), milkings with kick-offs (KO), and teat not found also showed low heritabilities (0.002-0.06). Due to low frequency, KO, rejected milkings, IM, and teat not found were also analyzed as proportions per lactation, which resulted in slightly higher heritability estimates. Genetic correlations were favorable and intermediate to strong between BT, HT, MEF, and FR with absolute values above 0.50. Intermediate and favorable correlations were found for IM and KO with BT, HT, MEF, and FR. Cow milkability in AMS can be improved by selection for reduced number of unsuccessful milkings, faster FR, increased MEF, and shorter BT and HT. Our results confirm that automatically recorded data on milkability and temperament can be valuable sources of information for routine genetic evaluations and that milking efficiency in AMS can be genetically improved.


Assuntos
Bovinos/genética , Indústria de Laticínios/instrumentação , Lactação/genética , Temperamento , Animais , Indústria de Laticínios/métodos , Feminino , Testes Genéticos , Glândulas Mamárias Animais , Leite , Noruega , Fenótipo , Característica Quantitativa Herdável , Reprodutibilidade dos Testes
20.
J Dairy Sci ; 102(9): 7664-7683, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31255270

RESUMO

An important goal in animal breeding is to improve longitudinal traits; that is, traits recorded multiple times during an individual's lifetime or physiological cycle. Longitudinal traits were first genetically evaluated based on accumulated phenotypic expression, phenotypic expression at specific time points, or repeatability models. Until now, the genetic evaluation of longitudinal traits has mainly focused on using random regression models (RRM). Random regression models enable fitting random genetic and environmental effects over time, which results in higher accuracy of estimated breeding values compared with other statistical approaches. In addition, RRM provide insights about temporal variation of biological processes and the physiological implications underlying the studied traits. Despite the fact that genomic information has substantially contributed to increase the rates of genetic progress for a variety of economically important traits in several livestock species, less attention has been given to longitudinal traits in recent years. However, including genomic information to evaluate longitudinal traits using RRM is a feasible alternative to yield more accurate selection and culling decisions, because selection of young animals may be based on the complete pattern of the production curve with higher accuracy compared with the use of traditional parent average (i.e., without genomic information). Moreover, RRM can be used to estimate SNP effects over time in genome-wide association studies. Thus, by analyzing marker associations over time, regions with higher effects at specific points in time are more likely to be identified. Despite the advances in applications of RRM in genetic evaluations, more research is needed to successfully combine RRM and genomic information. Future research should provide a better understanding of the temporal variation of biological processes and their physiological implications underlying the longitudinal traits.


Assuntos
Cruzamento/métodos , Genômica , Característica Quantitativa Herdável , Animais , Lactação/genética , Gado/genética , Modelos Genéticos , Fenótipo , Polimorfismo de Nucleotídeo Único/genética , Análise de Regressão
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