Resolving the aphid resistance locus Sd-1 on a BAC contig within a sub-telomeric region of Malus linkage group 7

Genome ◽  
2002 ◽  
Vol 45 (5) ◽  
pp. 939-945 ◽  
Author(s):  
Volkan Cevik ◽  
Graham J King
Keyword(s):  
Linkage Group ◽  
Physical Map ◽  
Aphid Resistance ◽  
Economic Damage ◽  
Telomeric Region ◽  
Resistance Locus ◽  
Average Insert Size ◽  
Distance Ratio ◽  
Bac Contig ◽  
Bac Clones

Aphids cause serious physical and economic damage to most major crops throughout the world, and there is a pressing requirement to isolate genes conferring aphid resistance. The Sd-1 locus in Malus spp. (apple) confers resistance against the rosy leaf-curling aphid (Dysaphis devecta Wlk.), and was recently positioned within a 1.3-cM region on linkage group 7, flanked by molecular markers. These markers were used as a basis for development of a BAC contig spanning the locus, together with adapter-mediated amplification of flanking sequences to obtain BAC insert-end sequences, and fingerprinting of BAC clones. Approximately 800 kb of the Sd-1 genomic region was covered by 19 overlapping BACs, with an average insert size of 75–150 kb. The physical – genetic distance ratio was estimated at 460 kb/cM, although the distribution of recombination events was irregular with respect to estimated physical distance. Recombinant analysis and development of new markers allowed Sd-1 to be positioned within an interval of approximately 180 kb located on either of two overlapping BACs. From one of these, an insert end sequence showed a significant degree of similarity to nucleotide binding site – leucine rich repeat (NBS–LRR) resistance genes. Fluorescent in situ hybridization (FISH) of BAC clones within the contig enabled positioning and orientation of the locus within a euchromatic region, very close to the telomere of linkage group 7.Key words: aphid, resistance gene, apple, Malus, physical map.

scholarly journals Genetic and Physical Mapping of Avr1a in Phytophthora sojae

Genetics ◽  
2002 ◽  
Vol 160 (3) ◽  
pp. 949-959 ◽  
Author(s):  
Terry MacGregor ◽  
Madan Bhattacharyya ◽  
Brett Tyler ◽  
Ravindra Bhat ◽  
August F Schmitthenner ◽  
...  
Keyword(s):  
Positional Cloning ◽  
Dna Marker ◽  
Physical Map ◽  
Phytophthora Sojae ◽  
Distance Ratio ◽  
Bac Contig ◽  
F2 Population ◽  
Genetic Linkage Maps ◽  
F2 Progeny ◽  
Avr Genes

Abstract The interaction between soybean and the phytopathogenic oomycete Phytophthora sojae is controlled by host resistance (Rps) genes and pathogen avirulence (Avr) genes. We have mapped the Avr1a locus in F2 populations derived from four different P. sojae races. Four RAPD and nine AFLP markers linked to Avr1a were initially identified. Nine markers were used to compare genetic linkage maps of the Avr1a locus in two distinct F2 populations. Distorted segregation ratios favoring homozygous genotypes were noted in both crosses. Segregation analysis of all the markers in one F2 population of 90 progeny generated a map of 113.2 cM encompassing Avr1a, with one marker cosegregating with the gene. The cosegregating DNA marker was used to isolate P. sojae BAC clones and construct a physical map covering 170 kb, from which additional DNA markers were developed. Three markers occurring within the BAC contig were mapped in an enlarged population of 486 F2 progeny. Avr1a was localized to a 114-kb interval, and an average physical to genetic distance ratio of 391 kb/cM was calculated for this region. This work provides a basis for the positional cloning of Avr1a.

Construction of a bacterial artificial chromosome (BAC) library for potato molecular cytogenetics research

Genome ◽  
2000 ◽  
Vol 43 (1) ◽  
pp. 199-204 ◽  
Author(s):  
Junqi Song ◽  
Fenggao Dong ◽  
Jiming Jiang
Keyword(s):  
Bacterial Artificial Chromosome ◽  
Physical Map ◽  
Molecular Cytogenetics ◽  
Bac Library ◽  
Artificial Chromosome ◽  
Average Insert Size ◽  
Chromosome Identification ◽  
Insert Size ◽  
Potato Genome ◽  
Bac Clones

Lack of reliable techniques for chromosome identification is the major obstacle for cytogenetics research in plant species with large numbers of small chromosomes. To promote molecular cytogenetics research of potato (Solanum tuberosum, 2n = 4x = 48) we developed a bacterial artificial chromosome (BAC) library of a diploid potato species S. bulbocastanum. The library consists of 23 808 clones with an average insert size of 155 kb, and represents approximately 3.7 equivalents to the potato genome. The majority of the clones in the BAC library generated distinct signals on specific potato chromosomes using fluorescence in situ hybridization (FISH). The hybridization signals provide excellent cytological markers to tag individual potato chromosomes. We also demonstrated that the BAC clones can be mapped to specific positions on meiotic pachytene chromosomes. The excellent resolution of pachytene FISH can be used to construct a physical map of potato by mapping molecular marker-targeted BAC clones on pachytene chromosomes. Key words: potato, BAC library, chromosome identification, physical mapping, molecular cytogenetics.

Fine mapping of the rosy apple aphid resistance locus Dp-fl on linkage group 8 of the apple cultivar ‘Florina’

2016 ◽  
Vol 12 (3) ◽  
Author(s):  
G. Pagliarani ◽  
E. Dapena ◽  
M. Miñarro ◽  
C. Denancé ◽  
Y. Lespinasse ◽  
...  
Keyword(s):  
Linkage Group ◽  
Fine Mapping ◽  
Aphid Resistance ◽  
Resistance Locus ◽  
Apple Cultivar

scholarly journals 484 Constructing the BAC Contig for the Evergreen Gene Region in Peach [Prunus persica (L.) Batsch]

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 477E-478
Author(s):  
Ying Wang ◽  
Laura L. George ◽  
Gregory L. Reighard ◽  
Ralph Scorza ◽  
Albert G. Abbott
Keyword(s):  
Prunus Persica ◽  
Physical Map ◽  
Single Gene ◽  
Bac Library ◽  
Gene Region ◽  
Average Insert Size ◽  
Insert Size ◽  
Bac Clone ◽  
Bac Contig ◽  
Peach Genome

Evergreen genotypes of peach [Prunus persica (L.) Batsch] have been identified in Mexico, where terminal growth on evergreen trees is continuous under favorable environmental conditions. This evergreen trait in peach is controlled by one single gene (evg), and this evergreen condition is homozygous recessive. Four dominant AFLP markers, EAT/MCAC, ETT/MCCA2, EAT/MCTA, and ETT/MACC, were found to be tightly linked to the evg locus at 1 cM, 4.6 cM, 5.8 cM, and 11 cM, respectively. All four markers were sequenced and identified. A peach BAC library was constructed by using the pBeloBAC11 vector for building the physical map for the evg gene. This library represents four times the coverage of the peach genome with the average insert size of 50 to 70 kb. The EAT/MCAC AFLP marker fragment was used for screening the peach BAC library. A single BAC clone, 18F12, was confirmed to contain this fragment. The final BAC contig for this evg gene region and the potential homology between peach and Arabidopsis thaliana will be presented and discussed.

Linkage mapping of genes controlling resistance to white rust (Albugo candida) in Brassica rapa (syn. campestris) and comparative mapping to Brassica napus and Arabidopsis thaliana

Genome ◽  
2002 ◽  
Vol 45 (1) ◽  
pp. 22-27 ◽  
Author(s):  
C Kole ◽  
P H Williams ◽  
S R Rimmer ◽  
T C Osborn
Keyword(s):  
Brassica Napus ◽  
Linkage Group ◽  
Brassica Rapa ◽  
Physical Map ◽  
Rflp Markers ◽  
Resistance Locus ◽  
Seedling Resistance ◽  
Albugo Candida ◽  
White Rust ◽  
Race 2

Genes for resistance to white rust (Albugo candida) in oilseed Brassica rapa were mapped using a recombinant inbred (RI) population and a genetic linkage map consisting of 144 restriction fragment length polymorphism (RFLP) markers and 3 phenotypic markers. Young seedlings were evaluated by inoculating cotyledons with A. candida race 2 (AC2) and race 7 (AC7) and scoring the interaction phenotype (IP) on a 0–9 scale. The IP of each line was nearly identical for the two races and the population showed bimodal distributions, suggesting that a single major gene (or tightly linked genes) controlled resistance to the two races. The IP scores were converted to categorical resistant and susceptible scores, and these data were used to map a single Mendelian gene controlling resistance to both races on linkage group 4 where resistance to race 2 had been mapped previously. A quantitative trait loci (QTL) mapping approach using the IP scores detected the same major resistance locus for both races, plus a second minor QTL effect for AC2 on linkage group 2. These results indicate that either a dominant allele at a single locus (Aca1) or two tightly linked loci control seedling resistance to both races of white rust in the biennial turnip rape cultivar Per. The map positions of white rust resistance genes in B. rapa and Brassica napus were compared and the results indicate where additional loci that have not been mapped may be located. Alignment of these maps to the physical map of the Arabidopsis genome identified regions to target for comparative fine mapping using this model organism.Key words: plant disease, oilseed Brassica, molecular markers.

scholarly journals Genetic and Molecular Characterization of the Maizerp3Rust Resistance Locus

Genetics ◽  
2002 ◽  
Vol 162 (1) ◽  
pp. 381-394 ◽  
Author(s):  
Craig A Webb ◽  
Todd E Richter ◽  
Nicholas C Collins ◽  
Marie Nicolas ◽  
Harold N Trick ◽  
...  
Keyword(s):  
Family Members ◽  
Crossing Over ◽  
Resistance Locus ◽  
Leucine Rich Repeat ◽  
Bac Contig ◽  
Puccinia Sorghi ◽  
Coding Regions ◽  
Complex Locus ◽  
Sequence Identities

AbstractIn maize, the Rp3 gene confers resistance to common rust caused by Puccinia sorghi. Flanking marker analysis of rust-susceptible rp3 variants suggested that most of them arose via unequal crossing over, indicating that rp3 is a complex locus like rp1. The PIC13 probe identifies a nucleotide binding site-leucine-rich repeat (NBS-LRR) gene family that maps to the complex. Rp3 variants show losses of PIC13 family members relative to the resistant parents when probed with PIC13, indicating that the Rp3 gene is a member of this family. Gel blots and sequence analysis suggest that at least 9 family members are at the locus in most Rp3-carrying lines and that at least 5 of these are transcribed in the Rp3-A haplotype. The coding regions of 14 family members, isolated from three different Rp3-carrying haplotypes, had DNA sequence identities from 93 to 99%. Partial sequencing of clones of a BAC contig spanning the rp3 locus in the maize inbred line B73 identified five different PIC13 paralogues in a region of ∼140 kb.

scholarly journals A4Mb High Resolution BAC Contig on Bovine Chromosome1q12and Comparative Analysis With Human Chromosome21q22

2005 ◽  
Vol 6 (4) ◽  
pp. 194-203 ◽  
Author(s):  
Cord Drögemüller ◽  
Anne Wöhlke ◽  
Tosso Leeb ◽  
Ottmar Distl
Keyword(s):  
Positional Cloning ◽  
Physical Map ◽  
Dominant Gene ◽  
Bac Library ◽  
Exact Order ◽  
Bac Contig ◽  
Nucleotide Sequence Data ◽  
New Genes ◽  
Human Genes ◽  
First Time

The bovine RPCI-42 BAC library was screened to construct a sequence-ready ~4 Mb single contig of 92 BAC clones on BTA 1q12. The contig covers the region between the genesKRTAP8P1andCLIC6. This genomic segment in cattle is of special interest as it contains the dominant gene responsible for the hornless or polled phenotype in cattle. The construction of the BAC contig was initiated by screening the bovine BAC library with heterologous cDNA probes derived from 12 human genes of the syntenic region on HSA 21q22. Contig building was facilitated by BAC end sequencing and chromosome walking. During the construction of the contig, 165 BAC end sequences and 109 single-copy STS markers were generated. For comparative mapping of 25 HSA 21q22 genes, genomic PCR primers were designed from bovine EST sequences and the gene-associated STSs mapped on the contig. Furthermore, bovine BAC end sequence comparisons against the human genome sequence revealed significant matches to HSA 21q22 and allowed thein silicomapping of two new genes in cattle. In total, 31 orthologues of human genes located on HSA 21q22 were directly mapped within the bovine BAC contig, of which 16 genes have been cloned and mapped for the first time in cattle. In contrast to the existing comparative bovine–human RH maps of this region, these results provide a better alignment and reveal a completely conserved gene order in this 4 Mb segment between cattle, human and mouse. The mapping of known polled linked BTA 1q12 microsatellite markers allowed the integration of the physical contig map with existing linkage maps of this region and also determined the exact order of these markers for the first time. Our physical map and transcript map may be useful for positional cloning of the putative polled gene in cattle. The nucleotide sequence data reported in this paper have been submitted to EMBL and have been assigned Accession Numbers AJ698510–AJ698674.

The genetic and RFLP characterization of the left end of linkage group III in Caenorhabditis elegans

Genome ◽  
1993 ◽  
Vol 36 (4) ◽  
pp. 712-724 ◽  
Author(s):  
Dave Pilgrim
Keyword(s):  
Caenorhabditis Elegans ◽  
Linkage Group ◽  
Genetic Map ◽  
Physical Map ◽  
Group Iii ◽  
C Elegans ◽  
Genomic Regions ◽  
Caenorhabditis Elegans Genome ◽  
Selection Of

A genetic approach was taken to identify new transposable element Tc1 -dependent polymorphisms on the left end of linkage group III in the nematode Caenorhabditis elegans. The cloning of the genomic DNA surrounding the Tc1 allowed the selection of overlapping clones (from the collection being used to assemble the physical map of the C. elegans genome). A contig of approximately 600–800 kbp in the region has been identified, the genetic map of the region has been refined, and 10 new RFLPs as well as at least four previously characterized genetic loci have been positioned onto the physical map, to the resolution of a few cosmids. This analysis demonstrated the ability to combine physical and genetic mapping for the rapid analysis of large genomic regions (0.5–1 Mbp) in genetically amenable eukaryotes.Key words: Caenorhabditis elegans, genome analysis, RFLP, physical map, genetic map.

Construction and characterization of bacterial artificial chromosome library of black-handed spider monkey (Ateles geoffroyi)

Genome ◽  
2004 ◽  
Vol 47 (2) ◽  
pp. 239-245 ◽  
Author(s):  
Yaping Qian ◽  
Li Jin ◽  
Bing Su
Keyword(s):  
Bacterial Artificial Chromosome ◽  
Large Scale ◽  
Bac Library ◽  
Artificial Chromosome ◽  
Spider Monkey ◽  
Ateles Geoffroyi ◽  
Comparative Genomic ◽  
Average Insert Size ◽  
Bac Clones ◽  
Genomic Study

The large-insert genomic DNA library is a critical resource for genome-wide genetic dissection of target species. We constructed a high-redundancy bacterial artificial chromosome (BAC) library of a New World monkey species, the black-handed spider monkey (Ateles geoffroyi). A total of 193 152 BAC clones were generated in this library. The average insert size of the BAC clones was estimated to be 184.6 kb with the small inserts (50-100 kb) accounting for less than 3% and the non-recombinant clones only 1.2%. Assuming a similar genome size with humans, the spider monkey BAC library has about 11× genome coverage. In addition, by end sequencing of randomly selected BAC clones, we generated 367 sequence tags for the library. When blasted against human genome, they showed a good correlation between the number of hit clones and the size of the chromosomes, an indication of unbiased chromosomal distribution of the library. This black-handed spider monkey BAC library would serve as a valuable resource in comparative genomic study and large-scale genome sequencing of nonhuman primates.Key words: black-handed spider monkeys, Ateles geoffroyi, BAC library.

scholarly journals The Rvi15 (Vr2) Apple Scab Resistance Locus Contains Three TIR-NBS-LRR Genes

2010 ◽  
Vol 23 (5) ◽  
pp. 608-617 ◽  
Author(s):  
Paolo Galli ◽  
Andrea Patocchi ◽  
Giovanni Antonio Lodovico Broggini ◽  
Cesare Gessler
Keyword(s):  
Venturia Inaequalis ◽  
Interleukin 1 ◽  
Apple Scab ◽  
Scab Resistance ◽  
Receptor Protein ◽  
Resistance Locus ◽  
Fresh Market ◽  
High Quality ◽  
Bac Clone ◽  
Bac Contig

Scab caused by the pathogen Venturia inaequalis is considered the most important fungal disease of cultivated apple (Malus × domestica Borkh.). In all, 16 monogenic resistances against scab have been found in different Malus spp. and some of them are currently used in apple breeding for scab-resistant cultivars. However, the self incompatibility and the long generation time of Malus spp. together with the high standards of fruit quality demanded from the fresh market render the breeding of high-quality cultivars in apple a long and expensive task. Therefore, the cloning of disease resistance genes and the use of the cloned genes for the transformation of high-quality apple cultivars could be an approach to solve these drawbacks. We report the construction of a bacterial artificial chromosome (BAC) contig spanning the Rvi15 (Vr2) apple scab resistance locus using two GMAL 2473 BAC libraries. A single BAC clone of the contig was sufficient to span the resistance locus. The BAC clone was completely sequenced, allowing identification of a sequence of 48.6 kb going from the two closest markers (ARGH17 and 77G20RP) bracketing Rvi15 (Vr2). Analysis of the 48.6-kb sequence revealed the presence of three putative genes characterized by a Toll and mammalian interleukin-1 receptor protein nucleotide-binding site leucine-rich repeat structure. All three genes were found to be transcribed.

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