Microsatellites, or simple sequence repeats (SSRs) are widespread class of repetitive DNA sequences, used in population genetics, genetic diversity and mapping studies. In spite of the SSR utility, the genetic and evolutionary mechanisms are not fully understood. We have investigated three microsatellite loci with different position in the pea (Pisum sativum L.) genome, the A9 locus residing in LTR region of abundant retrotransposon, AD270 as intergenic and AF016458 located in 5'untranslated region of expressed gene. Comparative analysis of a 35 pair samples from seven pea varieties propagated by single-seed descent for ten generations, revealed single 4 bp mutation in 10th generation sample at AD270 locus corresponding to stepwise increase in one additional ATCT repeat unit. The estimated mutation rate was 4.76 × 10(-3) per locus per generation, with a 95% confidence interval of 1.2 × 10(-4) to 2.7 × 10(-2). The comparison of cv. Bohatýr accessions retrieved from different collections, showed intra-, inter-accession variation and differences in flanking and repeat sequences. Fragment size and sequence alternations were also found in long term in vitro organogenic culture, established at 1983, indicative of somatic mutation process. The evidence of homoplasy was detected across of unrelated pea genotypes, which adversaly affects the reliability of diversity estimates not only for diverse germplasm but also highly bred material. The findings of this study have important implications for Pisum phylogeny studies, variety identification and registration process in pea breeding where mutation rate influences the genetic diversity and the effective population size estimates.

• MeSH
• 5' nepřekládaná oblast MeSH
• chov MeSH
• DNA rostlinná genetika   izolace a purifikace   MeSH
• genetická variace MeSH
• genom rostlinný MeSH
• genotyp MeSH
• hrách setý genetika   MeSH
• intergenová DNA MeSH
• koncové repetice MeSH
• mikrosatelitní repetice * MeSH
• mutace * MeSH
• nestabilita genomu MeSH
• retroelementy MeSH
• rodokmen * MeSH
• sekvenční analýza DNA MeSH
• semena rostlinná genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 5' nepřekládaná oblast MeSH
• DNA rostlinná MeSH
• intergenová DNA MeSH
• retroelementy MeSH

Retrotransposon segments were characterized and inter-retrotransposon amplified polymorphism (IRAP) markers developed for cultivated flax (Linum usitatissimum L.) and the Linum genus. Over 75 distinct long terminal repeat retrotransposon segments were cloned, the first set for Linum, and specific primers designed for them. IRAP was then used to evaluate genetic diversity among 708 accessions of cultivated flax comprising 143 landraces, 387 varieties, and 178 breeding lines. These included both traditional and modern, oil (86), fiber (351), and combined-use (271) accessions, originating from 36 countries, and 10 wild Linum species. The set of 10 most polymorphic primers yielded 141 reproducible informative data points per accession, with 52% polymorphism and a 0.34 Shannon diversity index. The maximal genetic diversity was detected among wild Linum species (100% IRAP polymorphism and 0.57 Jaccard similarity), while diversity within cultivated germplasm decreased from landraces (58%, 0.63) to breeding lines (48%, 0.85) and cultivars (50%, 0.81). Application of Bayesian methods for clustering resulted in the robust identification of 20 clusters of accessions, which were unstratified according to origin or user type. This indicates an overlap in genetic diversity despite disruptive selection for fiber versus oil types. Nevertheless, eight clusters contained high proportions (70-100%) of commercial cultivars, whereas two clusters were rich (60%) in landraces. These findings provide a basis for better flax germplasm management, core collection establishment, and exploration of diversity in breeding, as well as for exploration of the role of retrotransposons in flax genome dynamics.

• MeSH
• alely MeSH
• Bayesova věta MeSH
• chov MeSH
• DNA rostlinná izolace a purifikace   MeSH
• fylogeneze MeSH
• genetická variace * MeSH
• genetické markery * MeSH
• genom rostlinný MeSH
• genotyp MeSH
• len genetika   MeSH
• molekulární sekvence - údaje MeSH
• multigenová rodina MeSH
• polymorfismus genetický MeSH
• retroelementy * MeSH
• sekvence aminokyselin MeSH
• sekvenční analýza DNA MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA rostlinná MeSH
• genetické markery * MeSH
• retroelementy * MeSH