A SNP/microsatellite genetic linkage map of the Atlantic cod (Gadus morhua)

A first genetic linkage map of the Atlantic cod ( Gadus morhua ) was produced, based on segregation data from 12 full-sib families of Norwegian origin. The map contained 174 single nucleotide polymorphism markers and 33 microsatellites, distributed on 25 linkage groups and had a length of 1225 cM. A significant difference in recombination rates between sexes was found, the average ratio of female:male recombination rates being 1.78 ± 1.62 (SD).     

Revision of the plant geographical territories of Israel and Sinai

The phytogeographical territories of Israel and Sinai are revised using a large mass of species distribution data. With the help of chorotype frequencies for 25 km² individual squares in Israel, territories were defined on the basis of the first two most frequent chorotypes. The similarity of boundaries in the resulting phytogeographical map with a physiognomic map suggests that the latter may be used in preliminary stages of the preparation of plant geographical maps.     

Complete maps of IS1, IS2, IS3, IS4, IS5, IS30 and IS150 locations in Escherichia coli K12

Summary In this paper complete distribution maps are presented of the seven IS elements 1, 2, 3, 4, 5, 30 and 150. These maps were obtained during the construction of an almost complete restriction map of the Escherichia coli genome of K12 strain BHB2600. The positions of IS elements were correlated to this map. The distribution of integration sites of all IS types is nonrandom. Besides a large gap from 79 min to 96 min, there is a pronounced IS cluster at 6 min and another at 97 min, map locations that have low gene incidences on the classical map. One cluster coincides with a region of IS induced rearrangements. The IS distribution pattern was compared to patterns of strains W3110 and HB101.     

A chromosomal genetic map of Rhizobium sp. NGR234 generated with Tn5-Mob

Summary Rhizobium sp. NGR234 in a fast-growing Rhizobium strain with a broad host range. The location and role of chromosomal genes involved in cellular metabolism or in the legume symbioses is unknown. We isolated a series of auxotrophic and antibiotic resistant mutants of NGR234 and utilized a chromosome mobilization system based on Tn5-Mob and pJB3JI; Tn5-Mob donor strains behaved like Hfr strains, transferring the chromosome polarly at high frequency from a fixed point of insertion. The use of four different strains with Tn5-Mob located at different nutritional loci in crosses with double auxotrophic recipients, allowed us to build up a circular linkage map of NGR234 based on relative recombination frequencies. Also, symbiotically important genes identified by site-directed mutagenesis, such as hemA and ntrA, could be located and mapped on the chromosome.Abbreviations Tc tetracycline - Sp spectinomycin - Rif rifampicin - Km kanamycin     

Physical map of chloroplast DNA of aerial yam,Dioscorea bulbifera L.

Summary A physical map of chloroplast DNA (ctDNA) of aerial yam, Dioscorea bulbifera L. was constructed using three restriction endonucleases, PstI, SalI, and SmaI. In addition, a clone bank of the BamHI-digested fragments were generated, and the locations of most BamHI fragments on the map were also determined. The ctDNA of D. bulbifera was found to be a circular molecule with a total size of ca. 152 kb involving two inverted repeats of ca. 25.5 kb, and small and large single copy regions of ca. 18.5 and 83.4 kb, respectively. The genes for the large subunit of the ribulose 1,5-bisphosphate carboxylase (rbcL) and the ATP-synthase subunits and (atpB/atpE) were mapped.Contribution from the Plant Germ-plasm Institute and the Laboratory of Genetics (No. 504), Faculty of Agriculture, Kyoto University, Japan. The work was supported in part by a Grant-in-Aid (No. 60400005) from the Ministry of Education, Science and Culture, Japan     

Characterization of fall armyworm mitochondrial DNA (Lepidoptera: Noctuidae)

Mitochondrial DNA from the fall armyworm, Spodoptera frugiperda (J.E. Smith), was cloned and characterized using restriction enzyme mapping. Genome size is approximately 16.3 kilobase (Kb), consistent with that of most animals. Three fragments, 8.1 Kb, 6.2 Kb, and 2.0 Kb, were produced by digestion with restriction enzyme Xbal and cloned into a pUC19 vector. Twenty-nine restriction enzymes were used to generate a detailed physical restriction enzyme map of the three cloned fragments. These data represent the first detailed characterization of a lepidopteran mitochondrial genome. © 1992 Wiley-Liss, Inc.     

Mapping genes essential for embryo development in Arabidopsis thaliana.

Summary We have previously isolated and characterized over 90 recessive mutants of Arabidopsis thaliana defective in embryo development. These emb mutants have been shown to differ in lethal phase, extent of abnormal development, and response in culture. We demonstrate in this report the value and efficiency of mapping emb genes relative to visible and molecular markers. Sixteen genes essential for embryo development were mapped relative to visible markers by analyzing progeny of selfed F₁ plants. Embryonic lethals are now the most common type of visible marker included on the linkage map of Arabidopsis. Backcrosses were used in several cases to orient genes relative to adjacent markers. Three genes were located to chromosome arms with telotrisomics by screening for a reduction in the percentage of aborted seeds produced by F₁ plants. A restriction fragment length polymorphism (RFLP) mapping strategy that utilizes pooled EMB/EMB F₂ plants was devised to increase the efficiency of mapping embryonic lethals relative to molecular markers. This strategy was tested by demonstrating that the biol locus of Arabidopsis is within 0.5 cM of an existing RFLP marker. Mapping embryonic lethals with both visible and molecular markers may therefore help to identify large numbers of genes with essential functions in Arabidopsis.     

RFLP mapping using near-isogenic lines in the soybean [Glycine max (L.) Merr.]

Summary A molecular marker analysis of a near-isogenic line (NIL), its donor parent (DP), and its recurrent parent (RP) can provide information about linkages between molecular markers and a conventional marker introgressed into the NIL. If the DP and RP possess different alleles for a given molecular marker, and if the NIL possesses the same allele as the DP, then it is reasonable to presume a linkage between that molecular marker and the introgressed marker. In this study, we examined the utility of RFLPs as molecular markers for the NIL genemapping approach. The allelic status of fifteen RFLP loci was determined in 116 soybean RP/NIL/DP line sets; 66 of the Clark RP type and 50 of the Harosoy RP type. Of the 1740 possible allelic comparisons (116 NILs x 15 RFLP loci), 1638 were tested and 462 (33.9%) of those were informative (i.e., the RP and DP had different RFLP alleles). In 15 (3.2%) of these 462 cases the NIL possessed the DP-derived RFLP allele, leading to a presumption of linkage between the RFLP locus and the introgressed conventional marker locus. Two presumptive linkages, pK-3 — and pK-472 — Lf _i, were subsequently confirmed by cosegregation linkage analysis. Although not yet confirmed, two other associations, pk-7 ab and pK-229 — y ₉ seemed to be plausible linkages, primarily because the pk-7 — ab association was detected in two independently derived NILs and both markers of the pK-229 — y ₉ association were known to be linked to Pb. The data obtained in this investigation indicated that RFLP loci were useful molecular markers for the NIL gene-mapping technique.Published as Paper no. 9101, Journal Series, Nebraska Agric. Res. Div. Project no. 12-091. Research partially funded by a grant from the Nebraska Soybean Development, Utilization, and Marketing Board     

广东汉族健康人载脂蛋白AⅠ-CⅢl-AⅣ基因簇DNA多态性及其单倍型分布

本文研究了中国广东汉族健康人群apoAI-CⅢ-AIV基因簇DNA限制性内切酶PstI、SstI和EcoRI片段长度多态性。其中等位基因P_1,P_2,S_1,S_2,R_1和R_2的频率分别为0.98,0.02,0.96,0.04,0.90和0.10。经卡方检验符合Hardy-Weinbery氏遗传平衡,与其他种族比较,本文结果显示中国广东汉族人P_2等位基因频率低于日本人、亚洲印第安人和高加索人,S_2等位基因频率低于日本人、菲律宾人、沙特阿拉伯人和亚洲印第安人,而与高加索人相近,R_2等位基因频率稍高于高加索人。不同种族间apoAI-CⅢ-AIV基因簇DNA多态频率无疑存在差异,这种差异可能是由于遗传漂变和自然选择单独或联合作用所致。对P_1、P_2,S_1、S_2和R_1、R_2构成的单倍型和连锁平衡程度进行了分析,结果显示这些单倍型处于连锁不平衡状态。