scholarly journals Parental and Consensus Linkage Maps of Eucalyptus globulus Using AFLP and Microsatellite Markers

2006 ◽  
Vol 55 (1-6) ◽  
pp. 202-217 ◽  
Author(s):  
J. S. Freeman ◽  
B. M. Potts ◽  
M. Shepherd ◽  
R. E. Vaillancourt

AbstractParental and consensus maps were constructed in an F2 inter-provenance cross of Eucalyptus globulus, using amplified fragment length polymorphism (AFLP) and microsatellite (or simple sequence repeats [SSR]) markers. The female map had 12 linkage groups and 118 markers, comprising 33 SSR and 85 AFLP loci. The male map had 14 linkage groups and 130 markers comprising 36 SSR and 94 AFLP loci. The integrated map featured 10 linkage groups and 165 markers, including 33 SSR and 132 AFLP loci, a small 11th group was identified in the male parent. Moderate segregation distortion was detected, concentrated in gender specific groups. The strongest distortion was detected in the female parent for which causal mechanisms are discussed. The inclusion of SSR markers previously mapped in several different eucalypt species within the subgenus Symphyomyrtus (E. globulus, E. camaldulensis, and predominantly E. grandis and E. urophylla), allowed comparison of linkage groups across species and demonstrated that linkage orders previously reported in E. globulus, E. grandis and E. urophylla were largely conserved.

2001 ◽  
Vol 52 (12) ◽  
pp. 1143 ◽  
Author(s):  
M. J. Hayden ◽  
S. Khatkar ◽  
P. J. Sharp

The construction of genetic linkage maps from intraspecific crosses of bread wheat is slow and difficult due to very limited levels of polymorphism, which hinder the assignment of linkage groups to chromosomes and leave large genomic regions without markers. Simple sequence repeats (SSRs) reveal a higher incidence of polymorphism and are more informative than any other DNA marker, and are therefore considered a marker of choice for self-pollinating crops with little intraspecific polymorphism. However, the availability of SSRs in bread wheat is still limited. In this study, selectively amplified microsatellite (SAM) analysis was used to develop informative SSR markers to assist in the construction of an intraspecific wheat map. Three markers were developed for under-represented regions in the genetic map, and 7 for unassigned linkage groups. The latter SSRs permitted the chromosomal origin of 4 unassigned linkage groups to be determined. These results demonstrate the utility of SAM analysis for the targetted development of informative SSR markers to genomic regions of interest, and assignment of linkage groups to chromosomes. Furthermore, SAM analysis facilitates the development of markers for relatively short (<11) dinucleotide repeat sequences, a class of SSRs generally inaccessible to traditional hybridisation-based methods used to develop these markers.


2003 ◽  
Vol 54 (12) ◽  
pp. 1173 ◽  
Author(s):  
A. Karakousis ◽  
J. P. Gustafson ◽  
K. J. Chalmers ◽  
A. R. Barr ◽  
P. Langridge

A consensus map of barley combining simple sequence repeat (SSR), restriction fragment length polymorphism (RFLP), and amplified fragment length polymorphism (AFLP) markers has been developed by combining 5 Australian barley linkage maps, Galleon × Haruna Nijo, Chebec × Harrington, Clipper × Sahara, Alexis × Sloop, and Amaji Nijo × WI2585, using the software package JOINMAP 2.0. The new consensus map consists of 700 markers, with 136 being SSRs, and has a total genetic distance of 933 cM. The consensus map order appears to be in good agreement with the Australian barley linkage maps, with the exception of a small inversion located close to the centromere of chromosome 5H. Similarly, the SSR map orders are in good agreement with SSR markers integrated into the doubled haploid linkage map of Lina × Hordeum spontaneum, Canada Park. The new consensus map provides a framework to cross examine and align partial and complete barley linkage maps using markers common to many barley maps. This map will allow researchers to rapidly and accurately select SSR markers for chromosome regions of interest for barley genetic and plant breeding studies.


2010 ◽  
Vol 135 (6) ◽  
pp. 511-520 ◽  
Author(s):  
Karen R. Harris-Shultz ◽  
Brian M. Schwartz ◽  
Wayne W. Hanna ◽  
Jeff A. Brady

Genetic linkage maps of bermudagrass (Cynodon spp.) species using 118 triploid individuals derived from a cross of T89 [C. dactylon (2n = 4x = 36)] and T574 [C. transvaalensis (2n = 2x = 18)] were enriched with expressed sequence tags-derived simple sequence repeat (EST-SSR) markers. Primers were developed from 53 ESTs containing SSRs producing 75 segregating markers from which 28 could be mapped to the T89 and T574 genetic maps. With the addition of previously generated marker data, 26 T89 linkage groups and eight T574 linkage groups were formed using a log-of-odds (LOD) value of 4.0. The T89 and T574 linkage maps spanned 1055 cM and 311.1 cM and include 125 and 36 single-dose amplified fragments (SDAFs), respectively. Many of the SDAFs displayed disomic segregation and thus T89 may be a segmental allotetraploid or an allotetraploid. The additional EST-SSR markers add value to the maps by increasing marker density and provide markers that can be easily transferred to other bermudagrass populations. Furthermore, EST-SSRs can be immediately used to assess genetic diversity, identify non-mutated cultivars of bermudagrass, confirm pedigrees, and differentiate contaminants from cultivars derived from ‘Tifgreen’.


Genome ◽  
2006 ◽  
Vol 49 (6) ◽  
pp. 648-656 ◽  
Author(s):  
Santiago García-Martínez ◽  
Lorella Andreani ◽  
Marta Garcia-Gusano ◽  
Filippo Geuna ◽  
Juan J Ruiz

Cultivated tomato (Solanum lycopersicum L.) germplasm shows limited genetic variation. Many DNA marker systems have been used for genetic diversity studies in wild and cultivated tomatoes, but their usefulness for characterizing phenotypic differences among very closely related cultivars remains uncertain. We have used 19 selected simple sequence repeat (SSR) markers and 7 amplified fragment length polymorphism (AFLP) primer combinations to characterize 48 cultivars of tomato, mainly traditional cultivars from the south-east of Spain. The main types were Solanum lycopersicum L. 'Muchamiel', 'De la pera', and 'Moruno'. The robustness of the dendrograms and the discrimination power reached with each marker type were similar. Unique fingerprinting even of the most closely related tomato cultivars could be obtained using a combination of some SSR and AFLP markers. A better grouping of the 'Muchamiel' cultivars was observed with SSR markers, whereas the grouping of cultivars of 'De la pera' type was best achieved with AFLPs. However, both types of markers adequately grouped cultivars of the main types, confirming the utility of SSR and AFLP markers for the identification of traditional cultivars of tomato.Key words: genetic variability, molecular markers, Solanum lycopersicum.


Genome ◽  
1995 ◽  
Vol 38 (4) ◽  
pp. 757-763 ◽  
Author(s):  
Shanmukhaswami S. Salimath ◽  
Antonio C. de Oliveira ◽  
Jeffrey L. Bennetzen ◽  
Ian D. Godwin

Finger millet (Eleusine coracana), an allotetraploid cereal, is widely cultivated in the arid and semiarid regions of the world. Three DNA marker techniques, restriction fragment length polymorphism (RFLP), randomly amplified polymorphic DNA (RAPD), and inter simple sequence repeat amplification (ISSR), were employed to analyze 22 accessions belonging to 5 species of Eleusine. An 8 probe – 3 enzyme RFLP combination, 18 RAPD primers, and 6 ISSR primers, respectively, revealed 14, 10, and 26% polymorphism in 17 accessions of E. coracana from Africa and Asia. These results indicated a very low level of DNA sequence variability in the finger millets but did allow each line to be distinguished. The different Eleusine species could be easily identified by DNA marker technology and the 16% intraspecific polymorphism exhibited by the two analyzed accessions of E. floccifolia suggested a much higher level of diversity in this species than in E. coracana. Between species, E. coracana and E. indica shared the most markers, while E. indica and E. tristachya shared a considerable number of markers, indicating that these three species form a close genetic assemblage within the Eleusine. Eleusine floccifolia and E. compressa were found to be the most divergent among the species examined. Comparison of RFLP, RAPD, and ISSR technologies, in terms of the quantity and quality of data output, indicated that ISSRs are particularly promising for the analysis of plant genome diversity.Key words: Eleusine coracana, finger millet, genome analysis, microsatellites, randomly amplified polymorphic DNA, restriction fragment length polymorphism, simple sequence repeats.


2021 ◽  
Vol 117 (3) ◽  
pp. 1
Author(s):  
Zahra SHEKARI ◽  
Zahra TAHMASEBI ◽  
Homayoun KANOUNI ◽  
Ali ashraf MEHRABI

<p class="042abstractstekst">Root structure modification can improve important agronomic traits including yield, drought tolerance and nutrient deficiency resistance. The aim of the present study was to investigate the diversity of root traits and to find simple sequence repeat (SSR) markers linked to root traits in chickpea (<em>Cicer arietinum </em>L.). This research was performed using 39 diverse accessions of chickpea. The results showed that there is significant variation in root traits among chickpea genotypes. A total of 26 alleles were detected 26 polymorphic bands were produced by 10 SSR markers in the eight linkage groups (LG). The results indicated that there is substantial variability present in chickpea<strong> </strong>germplasm for root traits.<strong> </strong>By analyzing the population structure, four subpopulations were identified.<strong> </strong>PsAS2, AF016458, 16549 and 19075 SSR markers on LG1, LG3, LG2 and LG1 linkage group respectively were<strong> </strong>associated with root traits<strong>.</strong> The research findings provide valuable information for improving root traits for chickpea breeders.</p>


Genome ◽  
1989 ◽  
Vol 31 (1) ◽  
pp. 137-142 ◽  
Author(s):  
M. D. Gale ◽  
P. J. Sharp ◽  
S. Chao ◽  
C. N. Law

A molecular map of wheat, Triticum aestivum, is being developed. Problems associated with the large genome size, the large number of linkage groups, polyploidy, and limited polymorphism at the DNA level are being overcome. In addition to the breeding applications expected from the map, various uses for restriction fragment length polymorphism markers as tools in cytogenetic manipulation of wheat chromosomes and those from related species are being found. These include identification of aneuploid genotypes, added precision in intervarietal chromosome manipulations, tests of chromosome stability, identification of alien chromosomes, and marker-aided introgression of genes of agronomic importance from related species.Key words: wheat, restriction fragment length polymorphism, genetic maps, aneuploidy, alien chromosomes.


2005 ◽  
Vol 35 (7) ◽  
pp. 1592-1603 ◽  
Author(s):  
Gancho T Slavov ◽  
Glenn T Howe ◽  
W Thomas Adams

Pollen contamination is detrimental to the genetic quality of seed orchard crops. Highly variable simple sequence repeat (SSR) markers make it possible to accurately measure pollen contamination and characterize patterns of within-orchard mating by directly identifying the male and female parent of each seed produced in the orchard. We used nine SSR markers to measure pollen contamination and characterize mating patterns based on seed samples collected in 3 years (1999, 2000, and 2003) from one block of a nonisolated, open-pollinated, clonal seed orchard of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in western Oregon. Pollen contamination was consistently high across the 3 years (mean = 35.3%, range = 31.0%-41.3%) and appeared to result primarily from cross-pollination among the orchard blocks. Levels of pollen contamination varied substantially among clones and were higher in clones with early female receptivity (mean = 55.5%) than in those with either mid (mean = 36.4%) or late (mean = 28.3%) female receptivity. We detected low rates of self-pollination (mean = 1.8% per clone) and over 10-fold differences in the relative paternal contributions of the clones. There was a clear pattern of positive assortative mating with respect to floral phenology. This study illustrates that SSR markers are powerful tools for characterizing seed lots and improving the design and management of Douglas-fir seed orchards.


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