共查询到19条相似文献，搜索用时 234 毫秒
1.
2.
家蚕雌、雄蛹鉴别和分离是家蚕杂交种生产的必须环节。目前雌雄蛹鉴别、分离主要依靠熟练技术工人通过肉眼和手工进行。为了将来开发一种可以自动识别和分离雌雄蚕蛹的装置，选取6个品种的雌、雄蚕蛹各约20粒，建立了蚕蛹体形图像数据库。结果表明：从该数据库可以获得用以区分雌雄蚕蛹的体形数据。对蚕蛹体形图像数据库的初步应用显示：从数据库中获取的蛹体重、体长、体宽等，可以在一定程度上用于识别和区分不同品种的雌雄蛹体。本实验为进一步研究雌雄蛹体形特征，开发雌雄蛹分离装置提供了基础数据。 相似文献
3.
4.
<正> 家蚕白僵病是养蚕生产中常见的一种病害,它在每季蚕期均有发生。为了加强对家蚕白僵病的防治,提高养蚕经济效益。86年夏秋蚕期我们采用多菌灵对家蚕白僵病进行了防治试验。供试药品为25％多菌灵可湿性杀菌剂(江苏镇江农药厂生产)。夏蚕期供试蚕品种为苏_3·秋_3×苏_4,中秋蚕期为75新×7532。白僵菌种收贮自上期蚕五龄后期发病的白僵蚕,装在玻璃容器内,放在室内阴凉 相似文献
5.
家蚕蝇蛆病是一种在蚕业生产中较常见的病害,本研究利用蝇蛆成虫惧怕黑的特性,研究黑斑蚕抵抗蚕蝇蛆病的效果,为抗蝇蛆病专用蚕品种选育作初步探讨。此项研究,为进一步选育抗蝇蛆病家蚕专用品种奠定基础;同时,在蚕业生产上开创一种既绿色环保又经济的生物防病方法。 相似文献
6.
7.
<正> 家蚕斑纹限性品种的主要特征是,在蚕的幼虫体皮上,呈现斑纹的个体为雌,无斑纹的个体为雄。这样,在良种繁育上可以按照斑纹的有无迅速进行雌雄鉴别,从而节约劳力,提高经济效益。为什么会产生有斑纹个体为雌,无斑纹个体为雄的遗传现象呢?这要从基因载体的染色体谈起。我们知道,在家蚕 相似文献
8.
本文介绍了有关家蚕浓核病病毒的特征及分类，复制机制，病理作用以及家蚕浓核病征、诊断、发病规律和防治方法，并介绍了家蚕对三种浓核病病毒的抗性机制，提出防治家蚕浓核病的最有效方法是选育抗浓核病蚕品种。 相似文献
9.
10.
11.
12.
OBJECTIVE: To compare the results of 2 canine registries for classification of the hip joints for dysplasia by breed, and to relate the percentage of dysplastic dogs with body metric characteristics. SAMPLE POPULATION: Data on the ranking order of hip dysplasia by breed from 2 registries for 156 dog breeds. PROCEDURES: The prevalence of hip dysplasia listed by the Orthopedic Foundation for Animals (OFA) and the breed mean score according to the list of the British Veterinary Association (BVA) Kennel Club Hip Dysplasia scheme were related to weight and height as well as the body mass index (BMI; kg/m(2)) by breed. RESULTS: The OFA ranking order and the percentage of dysplastic dogs were highly correlated with the BVA mean score (rho = 0.74). A significant correlation was found between the prevalence of hip dysplasia and the BMI (r = 0.63). Receiver operating characteristic curve analysis revealed that the highest area under the curve, corresponding to the best discrimination, was at a BMI of 110 kg/m(2) with a criterion value of 15% dysplastic dogs (area under the curve, 0.89). Because the ratio of dogs in the positive and negative groups reflected the prevalence of the condition among breeds in the OFA database, the positive likelihood ratio was 9.32 and the negative likelihood ratio was 0.24. CONCLUSION AND CLINICAL RELEVANCE: The OFA statistics and the BVA mean scores reflected the prevalence of hip dysplasia among dog breeds. Body mass index accurately discriminated between breeds with high or low prevalence of hip dysplasia. 相似文献
13.
为了了解家蚕受BmNPV侵染后中肠蛋白质组变化规律,探讨家蚕抗BmNPV的基因。经过对秋丰、白玉等9个不同系统的家蚕品种抗性比较试验,筛选获得BmNPV感染发病率相差72个百分点的抗性品种P50和感性品种306。采用蛋白质双向电泳技术分析比较了P50和306两品种经口接种BmNPV当天（5龄第1天）的家蚕与第4天（5龄第4天）家蚕的中肠组织蛋白质变化图谱,结果发现这两个品种感染病毒当天各有10个互不相同的特异蛋白斑点,感染第4天后306品种发现33个特异蛋白斑点,P50发现14个特异蛋白斑点,两品种的特异蛋白斑点也各不相同。这些蛋白斑点可能分别与抗性品种的抗性和感性品种的易感性有关。 相似文献
14.
昆虫蜕皮激素受体(ecdysone receptor,EcR)是一种核内受体,为蜕皮激素的分子靶标。用0.002 g/L蜕皮激素溶液浸泡过的桑叶饲喂家蚕5龄幼虫,采用双跟踪标定定量PCR(dual-spike-in qPCR)方法,检测家蚕蜕皮激素受体基因BmEcR-A、BmEcR-B1和超气门蛋白(ultraspiracle,USP)基因BmUSP在家蚕幼虫马氏管、脂肪体、中肠组织的转录水平变化,分析蚕体组织以及BmEcR和BmUSP基因在蜕皮激素代谢过程中的作用与表达调控特征。结果表明:家蚕EcR的2种同工型基因BmEcR-A和BmEcR-B1的mRNA转录水平均变化显著,在脂肪体中的转录水平最高,其它组织相对较低;BmUSP的mRNA转录水平同样变化显著,且在脂肪体中的转录水平最高,马氏管次之,中肠最低。另检测正常情况下4龄眠期和5龄末期BmEcR-A、BmEcR-B1和BmUSP的mRNA转录水平相对于其它发育时期较高,且脂肪体中的转录水平要明显高于其它组织。BmEcR-A、BmEcR-B1和BmUSP均在家蚕幼虫脂肪体中高水平表达,表明了脂肪体在蜕皮激素代谢过程中的重要性。 相似文献
15.
I. Jeusette D. Greco F. Aquino M. Peterson C. Torre 《Research in veterinary science》2010,88(2):227-232
The objectives of this clinical study were firstly, to assess the effects of breed/genetic group on body composition in dogs using Dual-X-ray absorptiometry (DEXA) as the reference method and secondly, to check, in clinical field conditions, if methods easy to apply in veterinary practice [bioelectrical impedance (BIA), morphometric equations, body condition score and body mass index] can give similar body composition results to DEXA results, using canine breeds with very different genetic and morphologic backgrounds. 19 dogs from 6 breeds with different genetic origin were used. Results showed that breed differences exist regarding body composition in dogs. Body condition score and morphometric equation should be developed by breed or by groups of breeds for an accurate estimation of body composition of the various breeds of dogs with a different genetic background or morphology. Any of the other tested methodologies (BIA or morphometric equations) gave results in agreement with DEXA value, when dogs with different genetic background and morphologic characteristics are used, but BIA, eventually in combination with morphometric measurements, could be a method to develop to estimate fat-free mass in dogs of different breeds. 相似文献
16.
BmLSP基因启动子驱动DsRed在转基因家蚕中的表达分析 总被引：1，自引：0，他引：1
家蚕幼虫血清蛋白(BmLSP)是由脂肪体细胞合成的一种贮藏蛋白,是研究家蚕幼虫期发育调控的理想靶标。基于家蚕基因组数据,克隆了BmLSP基因5'端侧翼区～1.6 kb的调控序列,构建成以红色荧光蛋白基因DsRed为报告基因的pig-gyBac表达载体并进行转基因注射,在个体水平上验证该启动子的特性。结果表明:BmLSP-DsRed表达框以单拷贝形式整合至家蚕基因组;DsRed在转基因家蚕脂肪体中特异转录表达,其时期表达特征与BmLSP基因基本一致,随发育阶段的不同呈现有规律的变化,即幼虫期表达,但1龄、2龄眠期不表达,3龄、4龄眠期有微弱表达,上蔟后表达量逐渐降低直至化蛾阶段消失。提示BmLSP可能通过其启动子区的特异元件受激素的精确调控而行使功能。 相似文献
17.
Kuehn LA Keele JW Bennett GL McDaneld TG Smith TP Snelling WM Sonstegard TS Thallman RM 《Journal of animal science》2011,89(6):1742-1750
Knowledge of breed composition can be useful in multiple aspects of cattle production, and can be critical for analyzing the results of whole genome-wide association studies currently being conducted around the world. We examine the feasibility and accuracy of using genotype data from the most prevalent bovine genome-wide association studies platform, the Illumina BovineSNP50 array (Illumina Inc., San Diego, CA), to estimate breed composition for individual breeds of cattle. First, allele frequencies (of Illumina-defined allele B) of SNP on the array for each of 16 beef cattle breeds were defined by genotyping a large set of more than 2,000 bulls selected in cooperation with the respective breed associations to be representative of their breed. With these breed-specific allele frequencies, the breed compositions of approximately 2,000 two-, three-, and four-way cross (of 8 breeds) cattle produced at the US Meat Animal Research Center were predicted by using a simple multiple regression technique or Mendel (http://www.genetics.ucla.edu/software/mendel) and their genotypes from the Illumina BovineSNP50 array, and were then compared with pedigree-based estimates of breed composition. The accuracy of marker-based breed composition estimates was 89% when using either estimation method for all breeds except Angus and Red Angus (averaged 79%), based on comparing estimates with pedigree-based average breed composition. Accuracy increased to approximately 88% when these 2 breeds were combined into an aggregate Angus group. Additionally, we used a subset of these markers, approximately 3,000 that populate the Illumina Bovine3K (Illumina Inc.), to see whether breed composition could be estimated with similar accuracy when using this reduced panel of SNP makers. When breed composition was estimated using only SNP in common with the Bovine 3K array, accuracy was slightly reduced to 83%. These results suggest that SNP data from these arrays could be used to estimate breed composition in most US beef cattle in situations where pedigree is not known (e.g., multiple-sire natural service matings, non-source-verified animals in feedlots or at slaughter). This approach can aid analyses that depend on knowledge of breed composition, including identification and adjustment of breed-based population stratification, when performing genome-wide association studies on populations with incomplete pedigrees. In addition, SNP-based breed composition estimates may facilitate fitting cow germplasm to the environment, managing cattle in the feedlot, and tracing disease cases back to the geographic region or farm of origin. 相似文献
18.
Jingya Xu Yuhua Fu Yan Hu Lilin Yin Zhenshuang Tang Dong Yin Mengjin Zhu Mei Yu Xinyun Li Yang Zhou Shuhong Zhao Xiaolei Liu 《畜牧与生物技术杂志(英文版)》2021,(2):492-507
Background: A large number of pig breeds are distributed around the world, their features and characteristics vary among breeds, and they are valuable resources. Understanding the underlying genetic mechanisms that explain across-breed variation can help breeders develop improved pig breeds.Results: In this study, we performed GWAS using a standard mixed linear model with three types of genome variants(SNP, In Del, and CNV) that were identified from public, whole-genome, sequencing data sets. We used 469 pigs of 57 breeds, and we identified and analyzed approximately 19 million SNPs, 1.8 million In Dels, and 18,016 CNVs. We defined six biological phenotypes by the characteristics of breed features to identify the associated genome variants and candidate genes, which included coat color, ear shape, gradient zone, body weight, body length, and body height. A total of 37 candidate genes was identified, which included 27 that were reported previously(e.g., PLAG1 for body weight), but the other 10 were newly detected candidate genes(e.g., ADAMTS9 for coat color).Conclusion: Our study indicated that using GWAS across a modest number of breeds with high density genome variants provided efficient mapping of complex traits. 相似文献
19.
Assessment of genetic diversity is a prerequisite for the management and conservation of animal genetic resources. Appropriate
design of breeding programmes is therefore impossible for breeds that have not been adequately characterized either phenotypically
and/or genetically. Phenotypic characteristics are important in breed identification and classification in ways that farming
communities can relate with. This study phenotypically characterized two breeds of zebu cattle in Kenya. A total of 12 measurements
(face length, ear length, horn length, heart girth, height at withers, chest depth, body length, height at rump, pelvis width,
corpus length, pin bone width and tail length) were collected on 373 Maasai and 277 Kamba zebu kept by traditional farmers
in south-east Kenya. The data were classified on the basis of breed group, age group, sex and coat colour pattern. Breed group,
age group and sex significantly influenced all measurements. Coat colour pattern significantly influenced only height at withers,
corpus length, ear length and tail length. Except for horn and ear length, all the other measurements were significantly higher
for the Maasai zebu. Additionally, the Maasai zebu was taller than it was long. The opposite was true for the Kamba zebu.
The Maasai and Kamba zebus can be classified as medium-sized breeds; however, great variations exist in their body sizes within
and between the breeds. 相似文献