AFLP mapping of quantitative trait loci for yield-determining physiological characters in spring barley

 An amplified fragment length polymorphism (AFLP) map covering 965 cM was constructed using 94 recombinant inbred lines of a cross between the spring barley varieties Prisma and Apex. This map was employed to identify quantitative trait loci (QTLs) controlling plant height, yield and yield-determining physiological characters using an approximate multiple-QTL model, the MQM method. The seven physiological traits were parameters used in a process-based crop-growth model that predicts barley biomass production as affected by daily temperature and radiation. The traits were measured in experiments conducted over 2 years. Except for the relative growth rate of leaf area, all traits examined had at least one QTL in each year. QTLs and their effects were found to vary with developmental stages for one trait, the fraction of shoot biomass partitioned to leaves, that was measured at several stages. Most of the traits were associated, though to different extents, with the denso dwarfing gene (the height-reducing allele in Prisma) located on the long arm of chromosome 3. Some of the QTLs were mapped to similar positions in both years. The results in relation to effects of the dwarfing gene, the physiological basis for QTL×environment interaction, and the relative importance of the parameter traits with respect to yield, are discussed. Received: 17 September 1998 / Accepted: 28 December 1998     

MIC-A polymorphism in Japanese and a MIC-A-MIC-B null haplotype

 A polymorphic gene, MIC-A, is one of the MIC family of genes which is composed of a group of homologous genes interspersed in the class III and class I regions of the major histocompatibility complex. MIC-A is located 46 kilobases (kb) centromeric of HLA-B, and is preferentially expressed in the epithelial cells and intestinal mucosa. Recently, MIC-A and the closely related MIC-B were reported as the molecules that conferred specificity in the recognition by the V_δ1γδT cells. In the present study, polymorphic exons 2, 3, and 4 of the MIC-A gene were analyzed using the polymerase chain reaction-single-strand conformation polymorphism method. The number of patterns found in exons 2, 3, and 4 were 5, 6, and 4, respectively, in 114 healthy Japanese subjects. Eight MIC-A alleles were observed in Japanese individuals, among which one, tentatively named MIC-AMW, has not previously been reported. There was a strong linkage disequilibrium between MIC-A and HLA-B loci: each MIC-A allele showed strong association with a particular HLA-B group. In contrast, B*3901 showed association with multiple MIC-A alleles. Furthermore, the existence of a MIC-A-MIC-B null haplotype, which is associated with HLA-B*4801, was identified. In this haplotype, a large-scale deletion (of approximately 100 kb) including the entire MIC-A gene was indicated and the MIC-B gene possessed a stop codon. Received: 12 November 1998 / Revised: 18 January 1999     

A behavioural analysis of phase change in the desert locust

A programme of research into phase change in the desert locust, Schistocerca gregaria, is described. The ability to change phase between solitarious and gregarious forms in response to population density is a key feature of locusts and is central to their occasional yet catastrophic impact on humans. Phase polymorphism is an extreme form of phenotypic plasticity. The most labile phase characteristic is behaviour. It is argued that a fully integrated study of behavioural phase change provides a powerful tool for understanding both the mechanisms of phase change and locust population dynamics, both of which offer possibilities for improved management and control of desert locust plagues. An assay for measuring behavioural phase-state in individual locusts was derived, based on logistic regression analysis. Experiments are described that used the assay to quantify the time-course of behavioural change, both within the life of individual locusts and across generations. The locust-related stimuli that provoke behavioural gregarization were investigated. Complex interactions were found between tactile, visual and olfactory stimuli, with the former exerting the strongest effect. Behavioural analysis also directed a study of the mechanisms whereby adult females exert an epigenetic influence over the phase-state of their developing offspring. Female locusts use their experience of the extent and recency of being crowded to predict the probability that their offspring will emerge into a high-density population, and alter the development of their embryos accordingly through a gregarizing agent added to the foam that surrounds the eggs at laying. There is also a less pronounced paternal influence on hatchling phase-state. An understanding of the time-course of behavioural phase change led to a study of the effect of the fine-scale distribution of resources in the environment on interactions between individual locusts, and hence on phase change. This, in turn, stimulated an exploration of the implications of individual behavioural phase change for population dynamics. Cellular automata models were derived that explore the relationships between population density, density of food resources and the distribution of resources in the environment. The results of the simulation showed how the extent of gregarization within a population increases with rising population size relative to food abundance and increasing concentration of food resources. Of particular interest was the emergence of critical zones across particular combinations of resource abundance, resource distribution and population size, where a solitarious population would rapidly gregarize. The model provided the basis for further laboratory and field experiments, which are described.     

应用RAPD技术对不同基因组组合生物型遗传多态性的研究(英文)

利用ＲＡＰＤ技术对不同基因组合的鱼类进行了基因组指纹图谱构建,在ＤＮＡ水平上对基因组成分进行了分析,探讨了其遗传多态性。ＲＡＰＤ结果发现,在２６个随机引物扩增的产物中,平均每个个体观察到约１４２个ＲＡＰＤ标记,单个引物获得的标记平均为５．４。其中４个引物扩增的图谱可将不同的生物型区分开：Ｓ－２６引物的扩增图谱（Ｆｉｇ．１）可将红鲫（ＲＡ）与其它组合区分开,还可将鲤鲫杂种一倍体（ＣＡ）与鲫鲤杂种三倍体（ＣＡＡ）和人工复合三倍体鲤（ＣＣＡ）区分开;Ｓ－８引物（Ｆｉｇ．２）可区分开红鲤（ＲＣ）和镜鲤（ＭＣ）;Ｓ－４５引物（Ｆｉｇ．３）可区分开ＲＣ和ＣＡ;Ｓ－２２引物则可区分开ＣＡＡ和ＣＣＡ。六种生物型均存在基因组特异性的图谱即各自独特的“诊断性”图谱,作者由此建立了详细的分子标记检索表（Ｔａｂｌｅ１）。通过对ＲＡＰＤ图谱的量化分析,利用ＵＰＧＭＡ构建了不同生物型的遗传关系树图;反映了鲤鲫及各种组合生物型之间的遗传相似关系：ＲＣ和ＭＣ属同一种系,聚为一族;ＣＡＡ和ＣＡ基因组类型相同,聚为一族;ＣＣＡ虽自成一体,但可与ＣＡＡ和ＣＡ聚为一族;而ＲＡ与其它组合遗传距离较远,自成一族。ＲＡＰＤ的结果也表明各种生物型内个体间     

木耳属真菌rDNA特异性扩增片段的RFLP研究

对木耳属8个种25个菌株的ITS和28SrDNA5’端两个区域分别进行了PCR扩增和限制酶切片段长度多态性（RFLP）研究。ITS－RFMP研究结果表明,HaeⅢ可将黑木耳与其它种区分开,MspⅠ可将盾形木耳、角质木耳、琥珀木耳和黑木耳4个种区分开,而供试的HaeⅢ、TaqⅠ、HinfⅠ和MaPⅠ这四种限制酶均不能将皱木耳、大木耳、网脉木耳及毛木耳4个种区分开,表明它们之间的亲缘关系较近;结果还表明,ITS—rDNA拷贝在毛木耳和琥珀木耳种内是异质性的,而在黑木耳种内是同质性的。285rDNA-RFLP研究结果表明,供试的4种限制酶中,仅MspⅠ可将盾形木耳和角质木耳区分开,而不能将其它种区分开,这显示了28SrDNA序列在木耳属不同种间的保守性。     

家鸡血清酯酶遗传多态现象的发育遗传学初步研究

采用垂直平板聚丙烯酰胺凝胶电泳方法随机抽样了后备,初产和产蛋３个阶段的优黄２０００肉种鸡血清酯酶的遗传多态性,结果表明：血清酯酶Ｅｓ－１和Ｅｓ－２均存在遗传多态现象,Ｅｓ－１区检出２－３条多态性酶带,Ｅｓ－２区仅有１条带,表型为带的有或无。     

Body Fat,Resting and Exercise Blood Pressure and the Angiotensinogen M235T Polymorphism: The Heritage Family Study

RANKINEN, T., JACQUES GAGNON, LOUIS PÉRUSSE, TREVA RICE, ARTHUR s. LEON, JAMES s. SKINNER, JACK H. WILMORE, D. C. RAO, AND CLAUDE BOUCHARD. Body fat, resting and exercise blood pressure and the angiotensinogen M235T polymorphism: the Heritage family study. Obes Res. Objective: The association of resting and exercise blood pressure (BP) and fat mass with the angiotensinogen (AGT) M235T polymorphism was investigated in 522 sedentary Caucasian subjects from 99 families. Research Methods and Procedures: Resting BP was measured on two separate days, three times each day, and the mean of six valid measurements was used. Exercise BP was measured during a cycle ergometer test at a constant power output (50 W). Body composition was derived from underwater weighing and the AGT M235T polymorphism was typed with a polymerase chain reaction-based method. Results: Neither resting nor exercise BP was associated with the AGT genotypes. In mothers, the homozygotes for the T allele showed 8. 8 kg and 7. 1 kg greater (p = 0. 017) age-adjusted body fat mass (FM) than the MM homozygotes and heterozygotes, respectively. Sixty-nine percent of all TT homozygotes were found in the highest FM tertile, whereas only 16% of the MM homozygotes fell in the same tertile (p = 0. 008). Moreover, a significant interaction was seen between FM and T-allele carrier status in women with regard to resting diastolic BP (p = 0. 002). Among women with a FM≥24 kg, carriers of the T allele showed a 6. 3 mmHg higher diastolic blood pressure (DBP) than non-carriers whereas no difference was found in women with a FM less than 24 kg. A similar trend toward an interaction term was evident with resting systolic blood pressure (p = 0. 011) and exercise DBP (p = 0. 012). Body fat was not associated with the AGT polymorphism in fathers or in offspring. Discussion: These data suggest that the AGT M235T polymorphism is associated with body fatness in women, and that the relationship between DBP and AGT M235T polymorphism is dependent on FM in middle-aged sedentary normotensive women.     

Fitness of wild‐caught Drosophila melanogaster females: allozyme variants of GPDH, ADH, PGM, and EST

We have collected several hundred Drosophila melanogaster flies (near Davis, California), isolated them individually, without anesthesia, at the collecting site, and estimated the fitness components of the wild‐caught females under different environmental conditions. The fitness parameters measured are fecundity, oviposition rate, and productivity (egg‐to‐adult viability, development rate, and number of progeny). The environmental variables are two temperatures (22°C and 28°C) and two densities (‘scant’ and ‘crowded’). After the fitness measurements are completed for each individual female, its genotype is determined at four loci encoding enzymes: GPDH and ADH, located on chromosome II and PGM and EST‐C, located on chromosome III. Density has a large significant effect on productivity; temperature has significant effects on fecundity, oviposition rate, and development rate. The experiments show that allozyme polymorphisms are associated with selection effects. Fitness differences between allozyme genotypes occur for all fitness components, except oviposition rate. But which genotype is superior depends on the environmental conditions; heterozygotes exhibit higher fitness than homozygotes in a number of cases, but inferior in others. A unique feature of the present experiments is that the experimental flies are wild‐caught females rather than laboratory‐bred individuals. This revised version was published online in July 2006 with corrections to the Cover Date.     

Intraspecific and interspecific variation in the second internal transcribed spacer sequence for Metastrongylus (Nematoda: Metastrongyloidea) detected by high resolution PCR-linked restriction fragment length polymorphism

Metastrongylus species are important parasites of free-range pigs and wild boar, but little is known about the genetic make-up of natural populations. This study was undertaken to examine sequence variation in internal transcribed spacer 2 of ribosomal DNA within and among three species of Metastrongylus using PCR-linked restriction fragment length polymorphism analysis. In contrast to many other species of bursate nematodes, significant intraspecific variation was detected in restriction fragment length polymorphism profiles among individual worms. In spite of this, it was possible to identify the three species by their distinctive restriction profiles. The findings suggest that the internal transcribed spacer 2 region should be useful for analysing population variation within Metastrongylus species.