Genetic improvement

遗传改良
  • 文章类型: Journal Article
    未经批准:断奶前小牛和替代母牛的死亡率代表了巨大的经济损失,限制了群体的遗传改善和生长,并表明农场管理不善和动物福利状况。
    未经评估:目前,约旦奶牛和替代母牛死亡率和原因尚不清楚。因此,本研究的目的是确定约旦断奶前小牛和替代母牛的发病率和死亡原因.此外,研究中确定了死亡率的年龄和季节性分布.
    UNASSIGNED:本研究使用从农场管理记录软件中提取的3年(2016年1月至2018年12月)的数据。小牛的具体数据包括出生的日期和月份以及性别。健康相关数据包括死亡年龄,尸检结果,实验室发现,如果有的话,和推定诊断。使用MicrosoftWord10的Excel电子表格进行描述性分析以确定断奶前小牛和替代小母牛的3年总死亡率以及年死亡率。
    UNASSIGNED:仅在研究期间存活出生的雌性小牛(n=724)用于分析。小腿总死亡率为8.9%,年死亡率在5.9%至12%之间。大多数死亡发生在年龄小于50天的小牛中,平均年龄为17天。小腿死亡率存在季节性模式,大多数死亡发生在一年中较冷的月份(12月,一月,二月,和三月)。断奶前的小牛因肠毒血症(39%)和肺炎(30%)而死亡的人数最多。小牛死亡的其他原因是恶鼻溃疡(8%),肠炎(6%),败血症性沙门氏菌病(5%),脑膜炎(4%),瘤胃饮酒者(3%),吸入性肺炎(3%),化脓性关节炎(1%),和脐炎(1%)。总体3年母牛死亡率为4%。死亡母牛的平均年龄为8个月(范围3-23个月)。因神经系统疾病(37%)和肠毒血症(33%)而死亡的小母牛人数最多。小母牛死亡的其他原因是恶鼻溃疡(11%),肠道沙门氏菌病(7%),慢性瘤胃强直性(7%),和慢性肺炎(4%)。
    UNASSIGNED:本研究中提供的数据对于构建和实施有效的预防性健康计划以及改善农场管理实践以减少小牛和小母牛损失至关重要。
    Pre-weaning dairy calf and replacement heifer mortality represents significant economic loss, limits genetic improvement and growth of the herd, and indicates poor management and animal welfare status on the farm.
    Currently, the rates and causes of the dairy calf and replacement heifer mortality in Jordan are not known. Therefore, the objective of this study was to determine the incidence rates and causes of mortality of pre-weaning calves and replacement heifers in Jordan. In addition, the age and seasonal distribution of mortality are determined in the study.
    Data extracted from the farm management record software over 3 years (January 2016-December 2018) were used in this study. Calf-specific data included the day and month of birth and sex. Health-related data included age at death, necropsy findings, laboratory findings if available, and the presumptive diagnosis. Descriptive analysis was performed to determine the 3-year overall mortality rate as well as the yearly mortality rate in pre-weaning calves and replacement heifers using excel spreadsheets of Microsoft Word 10.
    Only female calves (n = 724) born alive during the study period were used in the analysis. The overall calf mortality rate was 8.9% with a yearly rate ranging between 5.9% and 12%. The majority of deaths occurred in calves less than 50 days of age with an average age of 17 days. There was a seasonal pattern for calf mortality with the majority of deaths occurring during the colder months of the year (December, January, February, and March). The highest number of pre-weaning calves died because of enterotoxemia (39%) and pneumonia (30%). Other causes of calf mortality were abomasal ulcer (8%), enteritis (6%), septicemic salmonellosis (5%), meningitis (4%), rumen drinkers (3%), aspiration pneumonia (3%), septic arthritis (1%), and omphalitis (1%). The overall 3-year heifer mortality rate was 4%. The average age of dead heifers was 8 months (range 3-23 months). The highest number of heifers died because of neurologic disease (37%) and enterotoxemia (33%). Other causes of heifer mortality were abomasal ulcer (11%), enteric salmonellosis (7%), chronic rumen tympany (7%), and chronic pneumonia (4%).
    Data presented in this study are essential to construct and implement effective preventative health programs and improve farm management practices to reduce calf and heifer losses.
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  • 文章类型: Journal Article
    小麦(TriticumaestivumL.)是一种主要作物,可养活世界40%的人口。在过去的几十年里,基因组学的进步在理解小麦的起源和驯化方面取得了巨大成就,以及农业重要性状的遗传基础,促进了优良品种的选育。在这次审查中,我们专注于基因组研究和谷物产量等性状的遗传改良方面取得的进展,最终用途特征,开花调节,养分利用效率,以及生物和非生物胁迫反应,以及主要由中国科学家贡献的各种育种策略。随着多个参考小麦基因组组件的可用性以及诸如精确基因组编辑工具等尖端技术的发展,小麦的功能基因组研究正在进入一个新时代。高通量表型平台,基于测序的克隆策略,高效遗传转化系统,和速育设施。这些见解将进一步扩展我们对农艺性状的分子机制和调控网络的理解,并促进育种过程,最终为中国和全世界更可持续的农业做出贡献。
    Bread wheat (Triticum aestivum L.) is a major crop that feeds 40% of the world\'s population. Over the past several decades, advances in genomics have led to tremendous achievements in understanding the origin and domestication of wheat, and the genetic basis of agronomically important traits, which promote the breeding of elite varieties. In this review, we focus on progress that has been made in genomic research and genetic improvement of traits such as grain yield, end-use traits, flowering regulation, nutrient use efficiency, and biotic and abiotic stress responses, and various breeding strategies that contributed mainly by Chinese scientists. Functional genomic research in wheat is entering a new era with the availability of multiple reference wheat genome assemblies and the development of cutting-edge technologies such as precise genome editing tools, high-throughput phenotyping platforms, sequencing-based cloning strategies, high-efficiency genetic transformation systems, and speed-breeding facilities. These insights will further extend our understanding of the molecular mechanisms and regulatory networks underlying agronomic traits and facilitate the breeding process, ultimately contributing to more sustainable agriculture in China and throughout the world.
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  • 文章类型: Journal Article
    当前的有机猪育种计划使用来自常规育种群体的猪。然而,传统生产系统和有机生产系统之间存在相当大的差异。这项模拟研究旨在评估有机猪行业如何从独立的育种计划中受益。模拟了两个有机猪育种计划:一个来自常规育种群体的二手父系(常规父系),和其他使用的父亲来自有机育种群体(有机父亲)。为了维持繁殖种群,常规种群使用常规育种目标,而有机种群使用有机育种目标。模拟了四个育种目标:一个常规育种目标,和三个有机育种目标。当使用传统的父亲时,有机种群的遗传增益遵循了传统的育种目标,即使使用有机育种目标来选择传统的父系。当使用有机父亲时,遗传增益遵循有机育种目标。从经济角度来看,用传统的母猪饲养有机猪是最好的,但前提是没有基因型与环境的相互作用。然而,这些结果表明,从生物学的角度来看,使用传统的父亲生物适应传统的生产系统的有机猪。
    Current organic pig-breeding programs use pigs from conventional breeding populations. However, there are considerable differences between conventional and organic production systems. This simulation study aims to evaluate how the organic pig sector could benefit from having an independent breeding program. Two organic pig-breeding programs were simulated: one used sires from a conventional breeding population (conventional sires), and the other used sires from an organic breeding population (organic sires). For maintaining the breeding population, the conventional population used a conventional breeding goal, whereas the organic population used an organic breeding goal. Four breeding goals were simulated: one conventional breeding goal, and three organic breeding goals. When conventional sires were used, genetic gain in the organic population followed the conventional breeding goal, even when an organic breeding goal was used to select conventional sires. When organic sires were used, genetic gain followed the organic breeding goal. From an economic point of view, using conventional sires for breeding organic pigs is best, but only if there are no genotype-by-environment interactions. However, these results show that from a biological standpoint, using conventional sires biologically adapts organic pigs for a conventional production system.
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  • 文章类型: Journal Article
    The population growth trend in recent decades has resulted in continuing efforts to guarantee food security in which leguminous plants, such as the common bean (Phaseolus vulgaris L.), play a particularly important role as they are relatively cheap and have high nutritional value. To meet this demand for food, the main target for genetic improvement programs is to increase productivity, which is a complex quantitative trait influenced by many component traits. This research aims to identify Quantitative Trait Nucleotides (QTNs) associated with productivity and its components using multi-locus genome-wide association studies. Ten morpho-agronomic traits [plant height (PH), first pod insertion height (FPIH), number of nodules (NN), pod length (PL), total number of pods per plant (NPP), number of locules per pod (LP), number of seeds per pod (SP), total seed weight per plant (TSW), 100-seed weight (W100), and grain yield (YLD)] were evaluated in four environments for 178 Mesoamerican common bean domesticated accessions belonging to the Brazilian Diversity Panel. In order to identify stable QTNs, only those identified by multiple methods (mrMLM, FASTmrMLM, pLARmEB, and ISIS EM-BLASSO) or in multiple environments were selected. Among the identified QTNs, 64 were detected at least thrice by different methods or in different environments, and 39 showed significant phenotypic differences between their corresponding alleles. The alleles that positively increased the corresponding traits, except PH (for which lower values are desired), were considered favorable alleles. The most influenced trait by the accumulation of favorable alleles was PH, showing a 51.7% reduction, while NN, TSW, YLD, FPIH, and NPP increased between 18 and 34%. Identifying QTNs in several environments (four environments and overall adjusted mean) and by multiple methods reinforces the reliability of the associations obtained and the importance of conducting these studies in multiple environments. Using these QTNs through molecular techniques for genetic improvement, such as marker-assisted selection or genomic selection, can be a strategy to increase common bean production.
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  • 文章类型: Journal Article
    The time to flowering (DF), pod beginning (DPB), seed formation (DSF), and maturity initiation (DMI) in soybean (Glycine max [L.] Merr) are important characteristics of growth stage traits (GSTs) in Chinese summer-sowing soybean, and are influenced by genetic as well as environmental factors. To better understand the molecular mechanism underlying the initiation times of GSTs, we investigated four GSTs of 309 diverse soybean accessions in six different environments and Best Linear Unbiased Prediction values. Furthermore, the genome-wide association study was conducted by a Fixed and random model Circulating Probability Unification method using over 60,000 single nucleotide polymorphism (SNP) markers to identify the significant quantitative trait nucleotide (QTN) regions with phenotypic data. As a result, 212 SNPs within 102 QTN regions were associated with four GSTs. Of which, eight stable regions were repeatedly detected in least three datasets for one GST. Interestingly, half of the QTN regions overlapped with previously reported quantitative trait loci or well-known soybean growth period genes. The hotspots associated with all GSTs were concentrated on chromosome 10. E2 (Glyma10g36600), a gene with a known function in regulating flowering and maturity in soybean, is also found on this chromosome. Thus, this genomic region may account for the strong correlation among the four GSTs. All the significant SNPs in the remaining 7 QTN regions could cause the significant phenotypic variation with both the major and minor alleles. Two hundred and seventy-five genes in soybean and their homologs in Arabidopsis were screened within ± 500 kb of 7 peak SNPs in the corresponding QTN regions. Most of the genes are involved in flowering, response to auxin stimulus, or regulation of seed germination, among others. The findings reported here provide an insight for genetic improvement which will aid in breeding of soybean cultivars that can be adapted to the various summer sowing areas in China and beyond.
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  • 文章类型: Journal Article
    大黄鱼(Larimichthyscrocea)是中国东南沿海最重要的养殖海洋鱼类之一。它的身体形状对水产养殖业很重要,因为它影响游泳等行为。摄取,逃避,以及客户偏好。由于小头消费需求较大,细长的身体大黄鱼,在遗传标记的帮助下选择和繁殖苗条的个体将使该行业迅速受益。在这项研究中,几个特征被用来代表身体形状,包括身体深度/身体长度(BD/BL),车身厚度/车身长度(BT/BL),尾柄深度/尾柄长度(CPDLR),尾长/体长(TL/BL),和身体面积/头部面积(BA/HA)。对280名个体进行了全基因组关联研究,以鉴定SNP和可能与体形相关的基因。确定12条染色体上的一组20个SNP与身体形状相关的性状显着相关。此外,5个SNP被鉴定为与CPDLR和BT/BL相关。围绕这些SNP,我们发现了一些与体型相关的候选基因,包括fabp1,acrv1,bcor,mstn,斑比,和neo1,参与脂质代谢,TGF-β信号,和BMP通路等重要调控通路。这些结果将有助于理解大黄鱼体形形成的遗传基础,并有助于通过标记辅助选择来控制大黄鱼的体形。
    Large yellow croaker (Larimichthys crocea) is one of the most important cultured marine fish on the southeast coast of China. Its body shape is important for the aquaculture industry since it affects the behavior such as swimming, ingesting, and evading, as well as customer preference. Due to the greater consumer demand of small head, slender body large yellow croaker, selecting and breeding of slender individuals with the assistance of genetic markers will benefit the industry quickly. In this study, several traits were employed to represent body shape, including body depth/body length (BD/BL), body thickness/body length (BT/BL), caudal peduncle depth/caudal peduncle length (CPDLR), tail length/body length (TL/BL), and body area/head area (BA/HA). Genome-wide association study was conducted with a panmictic population of 280 individuals to identify SNP and genes potentially associated with body shape. A set of 20 SNPs on 12 chromosomes were identified to be significantly associated with body shape-related traits. Besides, 5 SNPs were identified to be suggestive associated with CPDLR and BT/BL. Surrounding these SNPs, we found some body shape-related candidate genes, including fabp1, acrv1, bcor, mstn, bambi, and neo1, which involved in lipid metabolism, TGF-β signaling, and BMP pathway and other important regulatory pathways. These results will be useful for the understanding of the genetic basis of body shape formation and helpful for body shape controlling of large yellow croaker by using marker-assisted selection.
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  • 文章类型: Journal Article
    背景:作为光周期敏感和自花授粉的物种,生育期性状对大豆的适应性和产量起着重要作用。为了研究大豆生长期的遗传结构,我们使用一组278个大豆种质和34,710个单核苷酸多态性(SNPs)进行了全基因组关联研究(GWAS),这些多态性的次要等位基因频率(MAF)高于0.04,通过特异性位点扩增片段测序(SLAF-seq)检测到,平均测序深度为6.14倍.GWAS是通过压缩混合线性模型(CMLM)进行的,该模型涉及相对亲属关系和种群结构。
    结果:GWAS显示,37个显著的SNP峰与大豆开花时间或其他生育期相关性状相关,包括盛开,开始pod,满舱,开始的种子,在-log10(P)>3.75或-log10(P)>4.44的两个或两个以上环境中,全种子分布在14条染色体上,包括染色体1、2、3、5、6、9、11、12、13、14、15、17、18、19。14个SNP是新基因座,23个SNP位于已知的QTL或75kb附近。五个候选基因(Glyma.05G101800,Glyma.11G140100,Glyma.11G142900,Glyma.19G099700,Glyma.19G100900)位于四个重要SNP(Gm5_27111367,Gm11_10629613,Gm11_10950924)的每一侧的90kb基因组区域中。基于AT880.1的G这些基因编码FRI(FRIGIDA),PUB13(装置U型盒13),MYB59康斯坦斯,FUS3和FUS3蛋白分别可能在控制大豆生育期中起重要作用。
    结论:本研究确定了与大豆生长期性状相关的推测SNP标记,可用于大豆生育期性状的标记辅助选择。此外,预测了大豆开花时间调控可能的候选基因。
    BACKGROUND: As a photoperiod-sensitive and self-pollinated species, the growth periods traits play important roles in the adaptability and yield of soybean. To examine the genetic architecture of soybean growth periods, we performed a genome-wide association study (GWAS) using a panel of 278 soybean accessions and 34,710 single nucleotide polymorphisms (SNPs) with minor allele frequencies (MAF) higher than 0.04 detected by the specific-locus amplified fragment sequencing (SLAF-seq) with a 6.14-fold average sequencing depth. GWAS was conducted by a compressed mixed linear model (CMLM) involving in both relative kinship and population structure.
    RESULTS: GWAS revealed that 37 significant SNP peaks associated with soybean flowering time or other growth periods related traits including full bloom, beginning pod, full pod, beginning seed, and full seed in two or more environments at -log10(P) > 3.75 or -log10(P) > 4.44 were distributed on 14 chromosomes, including chromosome 1, 2, 3, 5, 6, 9, 11, 12, 13, 14, 15, 17, 18, 19. Fourteen SNPs were novel loci and 23 SNPs were located within known QTLs or 75 kb near the known SNPs. Five candidate genes (Glyma.05G101800, Glyma.11G140100, Glyma.11G142900, Glyma.19G099700, Glyma.19G100900) in a 90 kb genomic region of each side of four significant SNPs (Gm5_27111367, Gm11_10629613, Gm11_10950924, Gm19_34768458) based on the average LD decay were homologs of Arabidopsis flowering time genes of AT5G48385.1, AT3G46510.1, AT5G59780.3, AT1G28050.1, and AT3G26790.1. These genes encoding FRI (FRIGIDA), PUB13 (plant U-box 13), MYB59, CONSTANS, and FUS3 proteins respectively might play important roles in controlling soybean growth periods.
    CONCLUSIONS: This study identified putative SNP markers associated with soybean growth period traits, which could be used for the marker-assisted selection of soybean growth period traits. Furthermore, the possible candidate genes involved in the control of soybean flowering time were predicted.
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  • 文章类型: Journal Article
    我们进行了一项全基因组关联研究,以鉴定用Illumina牛HD770KSNP阵列分型的463头和牛肉牛的身体测量性状的候选基因。在全基因组水平上,我们检测到18个、5个和1个与臀高相关的SNP,身体高度和身体长度。总的来说,这些SNP在11个基因内或附近,其中六个(彭克,先前已经报道了XKR4,IMPAD1,PLAG1,CCND2和SNTG1),其中五个(CSMD3,LAP3,SYN3,FAM19A5和TIMP3)是我们发现与身体测量性状相关的新候选基因。对这些候选基因的进一步探索将有助于中国和牛肉牛的遗传改良。
    We performed a genome-wide association study to identify candidate genes for body measurement traits in 463 Wagyu beef cattle typed with the Illumina Bovine HD 770K SNP array. At the genome-wide level, we detected 18, five and one SNPs associated with hip height, body height and body length respectively. In total, these SNPs are within or near 11 genes, six of which (PENK, XKR4, IMPAD1, PLAG1, CCND2 and SNTG1) have been reported previously and five of which (CSMD3, LAP3, SYN3, FAM19A5 and TIMP3) are novel candidate genes that we found to be associated with body measurement traits. Further exploration of these candidate genes will facilitate genetic improvement in Chinese Wagyu beef cattle.
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  • 文章类型: Journal Article
    The search landscape is a common metaphor to describe the structure of computational search spaces. Different landscape metrics can be computed and used to predict search difficulty. Yet, the metaphor falls short in visualisation terms because it is hard to represent complex landscapes, both in terms of size and dimensionality. This paper combines local optima networks, as a compact representation of the global structure of a search space, and dimensionality reduction, using the t-distributed stochastic neighbour embedding algorithm, in order to both bring the metaphor to life and convey new insight into the search process. As a case study, two benchmark programs, under a genetic improvement bug-fixing scenario, are analysed and visualised using the proposed method. Local optima networks for both iterated local search and a hybrid genetic algorithm, across different neighbourhoods, are compared, highlighting the differences in how the landscape is explored.
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  • 文章类型: Journal Article
    Interest in genetic improvement of carcass and tenderness traits of beef cattle using genome-based selection (GS) and marker-assisted management programs is increasing. The success of such a program depends on the presence of linkage disequilibrium between the observed markers and the underlying QTL as well as on the relationship between the discovery, validation, and target populations. For molecular breeding values (MBV) predicted for a target population using SNP markers, reliabilities of these MBV can be obtained from validation analyses conducted in an independent population distinct from the discovery set. The objective of this study was to test MBV predicted for carcass and tenderness traits of beef cattle in a Canadian-based validation population that is largely independent of a United States-based discovery set. The discovery data set comprised of genotypes and phenotypes from >2,900 multibreed beef cattle while the validation population consisted of 802 crossbred feeder heifers and steers. A bivariate animal model that fitted actual phenotype and MBV was used for validation analyses. The reliability of MBV was defined as square of the genetic correlation (R(2) g) that represents the proportion of the additive genetic variance explained by the SNP markers. Several scenarios involving different starting marker panels (384, 3K, 7K, and 50K) and different sets of SNP selected to compute MBV (50, 100, 200, 375, 400, 600, and 800) were investigated. Validation results showed that the most reliable MBV (R(2) g) were 0.34 for HCW, 0.36 for back fat thickness, 0.28 for rib eye area, 0.30 for marbling score, 0.25 for yield grade, and 0.38 for Warner-Bratzler shear force across the different scenarios explored. The results indicate that smaller SNP panels can be developed for use in genetic improvement of beef carcass and tenderness traits to exploit GS benefits.
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