A consensus linkage map of barley

A consensus linkage map of the barley genome was constructed. The map is based on six doubled haploid and one F₂ population. The mapping data for three of the doubled haploid populations was obtained via the GrainGenes database. To allow merger of the maps, only RFLP markers that produce a single scorable band were included. Although this reduced the available markers by about half, the resultant map contains a total of 587 markers including 87 of known function. As expected, gene order was highly conserved between maps and all but two discrepancies were found in closely linked markers and are likely to result from the small population sizes used for some maps. The consensus map allows the rapid localisation of markers between published maps and should facilitate the selection of markers for high-density mapping in defined regions.     

The inheritance and chromosomal localization of AFLP markers in a non-inbred potato offspring

AFLP^TM is a new technique to generate large numbers of molecular markers for genetic mapping. The method involves the selective amplification of a limited number of DNA restriction fragments out of complex plant genomic DNA digests using PCR. With six primer combinations 264 segregating AFLP amplification products were identified in a diploid backcross population from non-inbred potato parents. The identity of an AFLP marker was specified by the primer combination of the amplification product and its size estimated in bases. The segregating AFLP amplification products were mapped by using a mapping population with 217 already known RFLP, isozyme and morphological trait loci. In general, the AFLP markers were randomly distributed over the genome, although a few clusters were observed. No indications were found that AFLP markers are present in other parts of the genome than those already covered by RFLP markers. Locus specificity of AFLP markers was demonstrated because equally sized amplification products segregating from both parental clones generally mapped to indistinguishable maternal and paternal map positions. Locus specificity of AFLP amplification products will allow to establish the chromosomal identity of linkage groups in future mapping studies.Since AFLP technology is a multi-locus detection system, it was not possible to identify the AFLP alleles which belong to a single AFLP locus. The consequences of a genetic analysis based on single alleles, rather than on loci with two or more alleles on mapping studies using progenies of non-inbred parents are discussed.     

Detection and Analysis of an Estrous－associated Oviductal Glycoprotein DNA Fragment from Primates by PCR

ＤｅｔｅｃｔｉｏｎａｎｄＡｎａｌｙｓｉｓｏｆａｎＥｓｔｒｏｕｓ－ａｓｓｏｃｉａｔｅｄＯｖｉｄｕｃｔａｌＧｌｙｃｏｐｒｏｔｅｉｎＤＮＡＦｒａｇｍｅｎｔｆｒｏｍＰｒｉｍａｔｅｓｂｙＰＣＲ￥ＣＨＥＮＱｉｎｇ－ｘｕａｎ（陈清轩）;ＣｌａｙｔｏｎＥ．Ｗａｌｔｏ...     

Fate of the anterior neural ridge and the morphogenesis of the xenopus forebrain

The fate of the anterior neural ridge was studied by following the relative movements of simultaneous spot applications of DiI and DiO from stage 15 through stage 45. These dye movements were mapped onto the neuroepithelium of the developing brain whose shape was gleaned from whole-mount in situs to neural cell adhesion molecule and dissections of the developing nervous system. The result is a model of the cell movements that drive the morphogenesis of the forebrain. The midanterior ridge moves inside and drops down along the most anterior wall of the neural tube. It then pushes forward a bit, rotates ventrally during forebrain flexing, and gives rise to the chiasmatic ridge and anterior hypothalamus. The midanterior plate drops, forming the floor of the forebrain ventricle, and, keeping its place behind the ridge, it gives rise to the posterior hypothalamus or infundibulum. The midlateral anterior ridge slides into the lateral anterior wall of the neural tube and stretches laterally into the optic stalk and retina, and then rotates into a ventral position. The lateral anterior ridge converges to the most anterior part of the dorsal midline during neural tube closure, then rotates anteriorly, and gives rise to telencephalic structures. Whole-mount bromodeoxyuridine labeling at these stages showed that cell division is widespread and relatively uniform throughout the brain during the late neurula and early tailbud stages, but that during late tailbud stages cell division becomes restricted to specific proliferative zones. We conclude that the early morphogenesis of the brain is carried out largely by choreographed cell movements and that later morphogenesis depends on spatially restricted patterns of cell division. © 1995 John Wiley & Sons, Inc.     

植物定植图微机显示与管理系统

介绍了运用软件工程的方法和数据库技术研究开发的南京中山植物园植物定植图微机显示与管理系统。详细介绍了系统的目标,系统的实现,应用软件的研制及应用效果。     

铜绿假单胞菌PIC－N萘降解基因的研究

铜绿假单胞菌（Ｐｓｅｕｄｏｍｏｎａｓａｅｒｕｇｉｎｏｓａ）ＰＩＣ－Ｎ对萘、邻苯二甲酸、水杨酸等有较强的氧化能力。发现该菌株以禁为底物可诱导产生芳香烃分解酶系。菌株中存在一个５７．４ｋｂ的质粒,经限制性内切酶ＨｉｎｄⅢ处理可产生７个片段,用限制性内切酶ＥｃｏＲⅠ处理可产生８个片段。将以限制性内切酶ＨｉｎｄⅢ部分酶切的片段克隆至大肠杆菌质粒ｐＭＦＹ４３上,获得２９个克隆株。通过对含有菌株ＰＩＣ－Ｎ质粒ＨｉｎｄⅢ片段的７个重组质粒进行限制酶分析,绘出了该质粒ＨｉｎｄⅢ内切酶７个切点的酶切图谱。     

An estimation of the genome length of maritime pine (Pinus pinaster Ait.)

The genome length, in units of Morgans or centimorgans, is a fundamental feature of a species. It can be calculated from a complete linkage map. However, the genome size can be estimated with partial linkage data. Using linkage data obtained by the analysis of a two-dimensional electrophoresis of the proteins contained in an haploid organ, the megagametophyte, we suggest an estimation and a confidence interval of the genome length of a gymnosperm, the maritime pine (Pinus pinaster Ait.). The results indicate an important gap between the physical and the genetic maps.     

Analysis of genome-specific sequences inPhleum species: Identification and use for study of genomic relationships

Sau3AI shot gun cloning and colony hybridization with total genomic probes were used to isolate genome-specific sequences inPhleum species. The total DNA isolated from diploid speciesP. alpinum andP. bertolonii was partially digested withSau3AI and cloned using pUC19 as a vector to anE. coli strain DH5mcr. A partial genomic DNA library consisting of 3030 colonies for the genome ofP. alpinum and one consisting of 3240 colonies for the genome ofP. bertolonii were constructed. Twelve hundred and thirty colonies from the DNA library ofP. alpinum and 1320 from that ofP. bertolonii were respectively blotted to membrane filters and hybridized to the total genomic probes from these two species. Eight clones specific toP. alpinum and 13 specific toP. bertolonii were isolated through colony hybridization and further dot-blot hybridization. Most of these clones may carry highly or moderately repetitive sequences. Three sequences specific toP. alpinum and 3 specific toP. bertolonii were used as probes to hybridize theEcoRI-digested DNA samples from four species,P. alpinum,P. bertolonii,P. pratense andP. montanum, on Southern blot. The results from these hybridization experiments showed that all 3P. bertolonii-specific probes and 2 of the 3P. alpinum-specific probes hybridized to the DNA ofP. pratense, thus confirming the conclusion of the close relationships between the cultivated timothy and its two wild relatives that was drawn in our previous study using the C-banding technique.     

A genetic linkage map of Picea abies Karst., based on RAPD markers,as a tool in population genetics

Norway spruce (Picea abies Karst.) is a most important species among European forest trees for both economical and ecological reasons. However, this species has suffered from a lack of information on the genetic side due to the scarcity of linkage data. In this study we have used a population of 72 megagametophytes from a single tree in a natural Italian stand to produce a genetic linkage map by means of RAPD markers. Ninety-six random decamers used as primers yielded 185 polymorphic loci showing Mendelian inheritance. Analysis of the segregation by multipoint analysis allowed us to define 17 major linkage groups covering a total distance of 3584 cM, with an average spacing between markers of 22 cM. Possible uses of a genetic linkage map with respect to population ecology and genetics are discussed.     

Construction and characterisation of a yeast artificial chromosome library containing five haploid sugarbeet (Beta vulgaris L.) genome equivalents

A yeast artificial chromosome (YAC) genomic library of Beta vulgaris was constructed in the pYAC4 vector. High-molecular-weight DNA was prepared from agarose-embedded leaf protoplasts from a triploid cultivar. The library was found to contain 33,500 clones in an ordered array of microtiter plates. Mean size of the inserts was estimated to be 135 kb, and the library should therefore represent the equivalent of five haploid genomes. The library was characterised for the presence of highly repetitive, chloroplast and single-copy sequences. In order to isolate single-copy sequences, 18 pools of DNA, each from 1920 individual YAC clones, were prepared for rapid screening of the library by the polymerase chain reaction. The results of these screenings showed that the number of isolated clones was at or near the frequency expected.