The molecular–genetic analysis of Triticum tauschii, the D-genome donor to hexaploid wheat

Genome ◽  
1991 ◽  
Vol 34 (3) ◽  
pp. 375-386 ◽  
Author(s):  
E. S. Lagudah ◽  
R. Appels ◽  
A. H. D. Brown ◽  
D. McNeil
Keyword(s):  
Restriction Fragment Length Polymorphism ◽  
Length Polymorphism ◽  
Fragment Length ◽  
Genetic Linkage ◽  
Genetic Linkage Map ◽  
Fragment Length Polymorphism ◽  
Repetitive Sequences ◽  
D Genome ◽  
Genome Donor ◽  
Restriction Fragment Length

DNA from Triticum tauschii (the D-genome donor to hexaploid wheat, Triticum aestivum) has been cloned using the restriction endonuclease PstI to generate fragments for insertion into the plasmid pBR322 or pUC118. A total of 143 clones were studied and demonstrated to contain one of the following sequence types: (i) a D-genome amplified repetitive sequence, (ii) polymorphic repetitive sequences ("fingerprint-type" sequences), (iii) polymorphic low to moderately repetitive sequences (PLR sequences), (iv) polymorphic low copy number sequences (PL sequences), and (v) invariant sequences. The D-genome amplified sequence was found to be located on all seven chromosomes. A genetic linkage map using PL and PLR sequences was produced by analysing F2 segregating progeny from crosses between two different taxa of T. tauschii. In addition to using DNA clones from T. tauschii, clones from other laboratories containing either anonymous sequences or genes coding for known products (e.g., 7S globulin, dehydrin, germin, storage protein) were used in the genetic linkage map. Multiple locations were mapped for the PLR sequences and were often clustered on single chromosomes. The restriction fragment length polymorphism markers and isozymes analysed were generally distributed over all the linkage groups that were identified and, when used in conjunction with published markers, provided the basis for a genetic map of T. tauschii.Key words: D genome, genetic linkage, restriction fragment length polymorphism, isozymes, chromosomal location.

scholarly journals Characterization of a Meiotic Crossover in Maize Identified by a Restriction Fragment Length Polymorphism-Based Method

Genetics ◽  
1996 ◽  
Vol 143 (4) ◽  
pp. 1771-1783 ◽  
Author(s):  
Marja C P Timmermans ◽  
O Prem Das ◽  
Joachim Messing
Keyword(s):  
Restriction Fragment Length Polymorphism ◽  
Restriction Fragment ◽  
Length Polymorphism ◽  
Meiotic Recombination ◽  
Fragment Length ◽  
Fragment Length Polymorphism ◽  
Repetitive Sequences ◽  
Crossover Site ◽  
Restriction Fragment Length

Abstract Genetic map lengths do not correlate directly with genome size, suggesting that meiotic recombination is not uniform throughout the genome. Further, the abundance of repeated sequences in plant genomes requires that crossing over is restricted to particular genomic regions. We used a physical mapping approach to identify these regions without the bias introduced by phenotypic selection. This approach is based on the detection of nonparental polymorphisms formed by recombination between polymorphic alleles. In an F2 population of 48 maize plants, we identified a crossover at two of the seven restriction fragment length polymorphism loci tested. Characterization of one recombination event revealed that the crossover mapped within a 534bp region of perfect homology between the parental alleles embedded in a 2773-bp unique sequence. No transcripts from this region could be detected. Sequences immediately surrounding the crossover site were not detectably methylated, except for an SstI site probably methylated via non-CpG or CpXpG cytosine methylation. Parental methylation patterns at this SstI site and at the flanking repetitive sequences were faithfully inherited by the recombinant allele. Our observations suggest that meiotic recombination in maize occurs between perfectly homologous sequences, within unmethylated, nonrepetitive regions of the genome.

Addition of Restriction Fragment Length Polymorphism Markers to the Genetic Linkage Map of Brassica rapa L. (syn. campestris)

2009 ◽  
Vol 64 (11-12) ◽  
pp. 882-890 ◽  
Author(s):  
Jogeswar Panigrahi ◽  
Anjana Patnaik ◽  
Phullara Kole ◽  
Chitta ranjan Kole
Keyword(s):  
Genetic Variation ◽  
Restriction Fragment Length Polymorphism ◽  
Brassica Rapa ◽  
Length Polymorphism ◽  
Fragment Length ◽  
Genetic Linkage ◽  
Fragment Length Polymorphism ◽  
Linkage Groups ◽  
Marker Interval ◽  
Restriction Fragment Length

Genetic linkage analysis of 151 restriction fragment length polymorphism (RFLP) loci, that included eight new loci, detected by the six probes in the present study, and four trait loci including seed colour, leaf pubescence, resistance to white rust caused by Albugo candida race-2 (AC-2) and race-7 (AC-7) employing the MAPMAKER/EXP 3.0 programme led to the development of 10 linkage groups (LGs) spanning over 44.4 centiMorgan (cM) to 130.4 cM containing 9 to 22 loci and two short LGs with two or three marker loci in Brassica rapa. The enriched map covers 993.1 cM of B. rapa genome with an average marker interval of 6.41. Eight new RFLP loci occupied new map positions on five linkage groups, LG 2, 3, 6, 8 and 9. Addition of these RFLP loci led to appreciable changes in the corresponding linkage groups and resulted in an increase of the total map length by 102.8 cM and of the marker interval by 0.35 cM. Interval mapping by using the computer programme MAPMAKER/ QTL 1.1 for scanning the genetic map led to the detection of one major quantitative trait locus (QTL) in LG 4 and one minor QTL in LG 8 governing resistance to AC-7. Both QTLs contributed 7.89 to the interaction phenotype (IP) score with 96.3% genetic variation. The multi-locus model suggested additive gene action with 96.8% genetic variation.

A genetic linkage map of restriction fragment length polymorphism loci for Brassica rapa (syn. campestris)

Genome ◽  
1992 ◽  
Vol 35 (5) ◽  
pp. 746-757 ◽  
Author(s):  
Y.-S. Chyi ◽  
M. E. Hoenecke ◽  
J. L. Sernyk
Keyword(s):  
Restriction Fragment Length Polymorphism ◽  
Linkage Map ◽  
Brassica Rapa ◽  
Restriction Fragment ◽  
Length Polymorphism ◽  
Fragment Length ◽  
Genetic Linkage Map ◽  
Fragment Length Polymorphism ◽  
Genome Structure ◽  
Restriction Fragment Length

A genetic linkage map has been constructed based on restriction fragment length polymorphism DNA markers for Brassica rapa L. using a segregating F2 progeny from a cross between the yellow sarson type 'R500' and the canola-type 'Horizon'. The map contains 360 marker loci detected by 269 genomic clones derived from a PstI library of 'Westar' (Brassica napus L.). The map consists of 10 linkage groups, covering a total of 1876 recombination units. The occurrence of substantial genome rearrangement during the evolution of B. rapa is evident from (i) a large number of homologous duplicate sequences either at genetically adjacent locations or in different linkage groups and (ii) a number of missing sequences in one or the other parental genome, detected as null alleles. Divergence of the parental genotypes is further supported by the frequency of loci with skewed allele segregation ratios. Comparison of molecular and cytogenetic data on genome structure is discussed. The probe set and map are being used to facilitate rapeseed breeding.Key words: Brassica campestris, Brassica rapa, genome structure, linkage map, restriction fragment length polymorphism.

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