畜禽遗传评定方法的研究进展

畜禽遗传评定是畜禽育种的重要内容。目前畜禽遗传评定方法中应用最广的是基于表型信息的BLUP动物模型。基因组学的发展和应用产生了大量分子遗传标记,结合分子遗传标记信息的遗传评定方法MBLUP随之产生。MBLUP将成为一种快速有效的畜禽遗传评定方法。本文主要介绍了畜禽遗传评定方法的研究进展和发展趋势。 Abstract:Genetic evaluation is one of the most important components in livestock breeding program.Best linear unbiased prediction (BLUP) Animal Model,which based on phenotypic information,has become the most widely accepted method for genetic evaluation of domestic livestock.Large numbers of molecular genetic markers have been discovered as the development and application of genomics.Some new methods (Marked Assisted BLUP,MBLUP) for genetic evaluation have being developed,which incorporating molecular genetic markers information into genetic evaluation.MBULP will be a rapid and efficient method for genetic evaluation of domestic livestock.The aim of the paper is to introduce the development and current situation of the methods for livestock genetic evaluation.     

内蒙古白绒山羊若干数量性状遗传参数的研究

本研究应用女母回归法、公畜内女母回归法、半同胞相关法和单元内半同胞相关法对内蒙古阿尔巴斯白绒山羊的产绒量、绒厚、毛长、体重、绒伸直长度和细度等六个性状的遗传参数进行了估测。结果表明：（1）绒量遗传力介于0.26～0.45之间;绒厚遗传力介于0.33～0.56之间;毛长遗传力介于0.23～0.32之间;体重的遗传力介于0.16～0.36之间;绒伸直长度遗传力为0.24;绒细度的遗传力为0.14。（2）产绒量与绒厚、绒厚与毛长、长度与绒厚、长度与毛长的遗传相关分别介于0.33～0.79、0.51～0.69、0.38～0.60、0.74～0.90之间,存在较强的正向遗传相关;绒量与毛长、绒量与体重、绒厚与体重、细度与绒厚、细度与绒量、细度与体重的遗传相关分别为0.11～0.38、0.06～0.17、0.15～0.36、0.02～0.11、0.24～0.35、0.13～0.32之间,存在较弱的正向遗传相关;毛长与体重、长度与绒量、长度与体重、长度与细度、细度与毛长之间的遗传相关介于-0.14～-0.28、-0.09～-0.20、-0.18～-0.23、-0.27～-0.31、-0.17～-0.28之间,存在中等偏弱的负向遗传相关。（3）绒量、绒厚、毛长、体重的重复率分别为0.42、0.27、0.59、0.18。 Abstract：Daughter-dam regression, daughter-dam regression wit hin sire, half-sib correlation and intro-unit half?sib correlation were used in the study to estimate genetic parameters for several traits of Albas type of In ner Mongolia cashmere goats, Traits included in this paper were cashmere yield ( CY),cashmere thickness(CT),staple length(SL),body eight(BW),cashmere stretched length(CSL) and cashmere fineness(CF).The results showed: (1)Heritabilities for CY,CT,SL and BW ranged between 0.26 and 0.45,between 0.33 and 0.56, between 0.23 and 0.32 and between 0.16 and 0.36 respectively; Heritabilities for SL and CF were 0.24 and 0.14 respectively.(2)Genetic correlations between CY and CT,between CT and SL ,between SL and CT and between CST and SL ranged 0.33～0. 79, 0.51～0.69, 0.38～0.60, and 0.74～0.90,respectively,and they belonged to high positive one;Genetic correlations between CY and SL, between CY and betw een CY and BW,between CT and BW, between CF and CT, between CF and CY and betwe en CF and BW ranged 0.11～0.38, 0.06～0.17,0.15～0.36, 0.02～0.11, 0.24 ～0.35 and 0.13～0.32,respectively, and they belonged to low positive correla tion;Genetic correlations between SL and BW, between SL and CY,between SL ?and BW, between? SL and CF and between CF and SL ranged -0.14～-0.28, -0.09～-0 .20, -0.18～-0.23,-0.27～-0.31,and -0.17～-0.28,respectively,and they belonged to low negative correlations.(3)Repeatabilities for CY,CT,SL and BW were 0.42,0.27,0.59 and 0.18,respectively.     

Index selection on seed traits under direct, cytoplasmic and maternal effects in multiple environments

Crop seeds are important sources of protein, oil, and carbohydrates for food, animal feeds, and industrial products. Recently, much attention has been paid to quality and functional properties of crop seeds. However, seed traits possess some distinct genetic characteristics in comparison with plant traits, which increase the difficulty of genetically improving these traits. In this study, diallel analysis for seed models with genotype by environment interaction （GE） effect was applied to estimate the variance-covariance components of seed traits. Mixed linear model approaches were used to estimate the genetic covariances between pair-wise seed and plant traits. The breeding values （BV） were divided into two categories for the seed models. The first category of BV was defined as the combination of direct additive, cytoplasmic, and maternal additive effects, which should be utilized for selecting stable cultivars over multi-environments. The three genetic effects, together with their GE interaction, were included in the second category of BV for selecting special lines to be grown in specific ecosystems. Accordingly, two types of selection indices for seed traits, i.e., general selection index and interaction selection index, were developed and constructed on the first and the second category BV, respectively. These proposed selection indices can be applied to solve the difficult task of simultaneously improving multiple seed traits in various environments. Data of crop seeds with regard to four seed traits and four yield traits based on the modified diallel crosses in Upland cotton （Gossypium hirsutum L.） were used as an example for demonstrating the proposed methodology.     

Characterization of 12 polymorphic microsatellite markers in the Chinese tree shrew (Tupaia belangeri chinensis)

The Chinese tree shrew (Tupaia belangeri chinensis) is a small experimental animal with a close affinity to primates. This species has long been proposed to be an alternative experimental animal to primates in biomedical research. Despite decades of study, there is no pure breed for this animal, and the overall genetic diversity of wild tree shrews remains largely unknown. In order to obtain a set of genetic markers for evaluating the genetic diversity of tree shrew wild populations and tracing the lineages in inbreeding populations, we developed 12 polymorphic microsatellite markers from the genomic DNA of the tree shrew. An analysis of a wild population of 117 individuals collected from the suburb of Kunming, China, showed that these loci exhibited a highly expected heterozygosity (0.616). These 12 microsatellites were sufficient for individual identification and parentage analysis. The microsatellite markers developed in this study will be of use in evaluating genetic diversity and lineage tracing for the tree shrew.     

Investigation of Combining Plant Genotypic Values and Molecular Marker Information for Constructing Core Subsets

In the present study, a strategy was proposed for constructing plant core subsets by clusters based on the combination of continuous data for genotypic values and discrete data for molecular marker InformaUon. A mixed linear model approach was used to predict genotyplc values for eliminating the environment effect. The ＂mixed genetic distance＂ was designed to solve the difficult problem of combining continuous and discrete data to construct a core subset by cluster. Four commonly used genetic distances for continuous data （Euclidean distance, standardized Euclidean distance, city block distance, and Mahalanobls distance） were used to assess the validity of the conUnuous data part of the mixed genetic distance; three commonly used genetic distances for discrete data （cosine distance, correlaUon distance, and Jaccard distance） were used to assess the validity of the discrete data part of the mixed genetic distance, A rice germplasm group with eight quantitative traits and information for 60 molecular markers was used to evaluate the validity of the new strategy. The results suggest that the validity of both parts of the mixed geneUc distance are equal to or higher than the common geneUc distance. The core subset constructed on the basis of a combination of data for genotyplc values and molecular marker information was more representative than that constructed on the basis of data from genotypic values or molecular marker informaUon alone. Moreover, the strategy of using combined data was able to treat dominant marker informaUon and could combine any other continuous data and discrete data together to perform cluster to construct a plant core subset.     

吉林爆玉米遗传距离与杂种优势关系的研究

根据吉林省80个爆玉米自交系数量性状的表现,估算了它们之间的遗传距离。又估算了这80个自交系间随机组配的67个杂交组合F1代小区产量、爆粒率和膨胀倍数的杂种优势。相关和回归分析表明,F1代产量的对照优势与其双亲之间的遗传距离呈显著的二次曲线关系,而F1代品质特性爆粒率和膨胀倍数的对照优势与其双亲之间的遗传距离无确定性关系。因此,可以根据亲本间数量性状的综合遗传差异——遗传距离来预测吉林省爆玉米杂种一代的产量优势。 An experiment was conducted in 1990 to 1991 at the university,to study the relationships between genetic distance,cluster analysis and heterosis in popcorn(Zea mays var.everta).Results showed that there is no sense in cludtering parental lines for prediction of yield heterosis,but blood pedigree can beidentifed from cluster analysis.The relation between genetic divergence or distance and yield heterosis of F1 hybrids can be predicted from the genetic distances of their parental lines according to this model,but no definite relation could be found between parental genetic divergence and the quality heterosis of F1 hybrids.     

Type Ⅰ interferon receptor knockout mice as models for infection of highly pathogenic viruses with outbreak potential

Due to their inability to generate a complete immune response, mice knockout for type Ⅰ interferon(IFN) receptors(Ifnar~(–/–)) are more susceptible to viral infections, and are thus commonly used for pathogenesis studies. This mouse model has been used to study many diseases caused by highly pathogenic viruses from many families, including the Flaviviridae, Filoviridae, Arenaviridae, Bunyaviridae, Henipaviridae, and Togaviridae. In this review, we summarize the findings from these animal studies, and discuss the pros and cons of using this model versus other known methods for studying pathogenesis in animals.     

The primary research on mouse and cat infected with A/Tiger/Harbin/01/2003(H5N1)

It was confirmed by WHOthat the H5N1viruses resultedinsevere or fatal respiratory disease inthe majority of infectedpersons,indicatingthat the H5N1viruses had crossedthe species barrier without genetic reassortment with a humanin-fluenza virus.To design more effective strategies for prevention and treatment of H5N1viruses infected,in the presentstudy,we used atiger original HPAIVA/Tiger/Harbin/01/2003(H5N1)propagated by SPFembryonated hen eggs to es-tablishinfected animal model.TCID5…     

Development of Oryza rufipogon and O. sativa Introgression Lines and Assessment for Yield-related Quantitative Trait Loci

Introgression lines population was effectively used in mapping quantitative trait loci （QTLs）, identifying favorable genes, discovering hidden genetic variation, evaluating the action or interaction of QTLs in multiple conditions and providing the favorable experimental materials for plant breeding and genetic research. In this study, an advanced backcross and consecutive selfing strategy was used to develop introgression lines （ILs）, which derived from an accession of Oryza rufipogon Griff. collected from Yuanjiang County, Yunnan Province of China, as the donor, and an elite indica cultivar Teqing （O. sativa L.）, as the recipient. Introgression segments from O. rufipogon were screened using 179 polymorphic simple sequence repeats （SSR） markers in the genome of each IL. Introgressed segments carried by the introgression lines population contained 120 ILs covering the whole O. rufipogon genome. The mean number of homozygous O. rufipogon segments per introgression line was about 3.88. The average length of introgressed segments was approximate 25.5 cM, and about 20.8% of these segments had sizes less than 10 cM. The genome of each IL harbored the chromosomal fragments of O. rufipogon ranging from 0.54% to 23.7%, with an overall average of 5.79%. At each locus, the ratio of substitution of O. rufipogon alleles had a range of 1.67-9.33, with an average of 5.50. A wide range of alterations in morphological and yield-related traits were also found in the introgression lines population. Using single-point analysis, a total of 37 putative QTLs for yield and yield components were detected at two sites with 7%-20% explaining the phenotypic variance. Nineteen QTLs （51.4%） were detected at both sites, and the alleles from O. rufipogon at fifteen loci （40.5%） improved the yield and yield components in the Teqing background. These O. rufipogon-O, sativa introgression lines will serve as genetic materials for identifying and using favorable genes from common wild rice.     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.