Mapping of digested and undigested random amplified microsatellite polymorphisms in barley

Genome ◽  
1995 ◽  
Vol 38 (5) ◽  
pp. 991-998 ◽  
Author(s):  
Jörg Becker ◽  
Manfred Heun

The broad use of microsatellites as a tool for constructing linkage maps in plants has been limited by the need for sequence data to detect the underlying simple sequence repeats. Therefore, random amplified microsatellite polymorphisms (RAMPs) were studied as an alternative approach for barley mapping. Labelled (GA)n simple sequence repeat primers were combined with RAPD primers of different length and sequence to generate RAMPs. To get additional polymorphisms (called dRAMPs), the obtained products were also analysed after digestion with MseI. There were 0–11 polymorphisms found per primer combination. Sixty RAMPs/dRAMPs identifying 40 new loci were mapped onto a barley RFLP map. The new DNA markers are found on all chromosomes and they increased the length of the barley map by 174 cM to a total of 1270 cM. Interestingly, the RAMPs/dRAMPs caused stretching effects in genome areas where stretching was also observed for AFLPs.Key words: barley, microsatellite, mapping, RAMP, RFLP.

Genome ◽  
1994 ◽  
Vol 37 (5) ◽  
pp. 763-769 ◽  
Author(s):  
M. Morgante ◽  
A. Rafalski ◽  
P. Biddle ◽  
S. Tingey ◽  
A. M. Olivieri

Microsatellites or simple sequence repeats are stretches of short tandemly repeated DNA sequence motifs, dispersed throughout the genomes of most eukaryotes. Simple sequence repeat polymorphisms (SSRPs) have recently been reported in plants. Here we present the genetic map position of seven different soybean (Glycine max (L.) Merr. and Glycine soja Sieb. and Zucc.) SSRPs contained in sequenced genes, four of which represent newly mapped positions for these genes. The other three SSRPs coincided with independently established RFLP map positions for the corresponding genes. When a set of 61 soybean accessions was screened at four of these loci by using agarose gels, the average number of alleles per locus was 7.75, the effective number of alleles (ne) was 2.57, and the level of allele differentiation (δT) was 0.62. Allelic variation decreased sharply with increasing levels of domestication, with the level of differentiation going from 84% in the wild soybean to 43% in the elite germplasm. Variation levels observed on a subset made of 19 of the 61 lines were always higher for SSRPs than for RFLP markers, with the average number of alleles per locus going from 4.25 to 2.15. In comparison with RFLP markers, SSRPs are more informative and are easier to analyse but require more effort to develop.Key words: simple sequence repeats, soybean, variability, mapping, domestication, microsatellites.


Genome ◽  
2000 ◽  
Vol 43 (2) ◽  
pp. 293-297 ◽  
Author(s):  
Muhammad H Rahman ◽  
S Dayanandan ◽  
Om P Rajora

Markers for eight new microsatellite DNA or simple sequence repeat (SSR) loci were developed and characterized in trembling aspen (Populus tremuloides) from a partial genomic library. Informativeness of these microsatellite DNA markers was examined by determining polymorphisms in 38 P. tremuloides individuals. Inheritance of selected markers was tested in progenies of controlled crosses. Six characterized SSR loci were of dinucleotide repeats (two perfect and four imperfect), and one each of trinucleotide and tetranucleotide repeats. The monomorphic SSR locus (PTR15) was of a compound imperfect dinucleotide repeat. The primers of one highly polymorphic SSR locus (PTR7) amplified two loci, and alleles could not be assigned to a specific locus. At the other six polymorphic loci, 25 alleles were detected in 38 P. tremuloides individuals; the number of alleles ranged from 2 to 7, with an average of 4.2 alleles per locus, and the observed heterozygosity ranged from 0.05 to 0.61, with an average of 0.36 per locus. The two perfect dinucleotide and one trinucleotide microsatellite DNA loci were the most informative. Microsatellite DNA variants of four SSR loci characterized previously followed a single-locus Mendelian inheritance pattern, whereas those of PTR7 from the present study showed a two-locus Mendelian inheritance pattern in controlled crosses. The microsatellite DNA markers developed and reported here could be used for assisting various genetic, breeding, biotechnology, genome mapping, conservation, and sustainable forest management programs in poplars. Key words: poplar, microsatellites, genetic mapping, simple sequence repeat (SSR) markers, DNA fingerprinting.


2000 ◽  
Vol 101 (1-2) ◽  
pp. 165-172 ◽  
Author(s):  
N. Diwan ◽  
J. H. Bouton ◽  
G. Kochert ◽  
P. B. Cregan

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