Isozyme relative mobility (R m ) changes related to leaf position; apparently smoothR m trends and some implications

Tyson, H.; Fieldes, Mary Ann; Cheung, Cindy; Starobin, Jean

doi:10.1007/bf00554080

Cited by 6 publications

(5 citation statements)

References 21 publications

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“…By consequently sampling the stem leaf first or second from the top it was attempted to avoid the electrophoretic phenotypes being affected by major differences in leaf position (cf. Tyson et al 1985).…”

Section: Methodsmentioning

confidence: 99%

Allozyme variation and genetic integrity of Dactylorhiza incarnata (Orchidaceae)

Pedersen

1998

Nordic Journal of Botany

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Eleven Danish populations of the diploid Dactylorhiza incarnata s.lat. have been examined for allozyme variation in DIA, PGD, PGI, PGM, SKD, TP1, and UGPP. The results reveal a deficiency of heterozygotes in several populations. Possible reasons for this deficiency are considered. The results also indicate that no genetic barrier seems to prevent gene flow between D. incarnata var. incarnata, var. dunensis, and var. ochrantha — and some indication exists that a considerable amount of gene exchange takes place between sympatric populations of var. incarnata and var. ochrantha. On the other hand, there is no sign of recent introgression between D. incarnata s.lat. and any of the sympatric tetraploid species (D. maculata, D. majalis, D. purpurella s.lat.). It is suggested that knowledge on the various degrees of genetic integrity of morphologically recognizable entities should be elaborated and subsequently utilized for a biosystematic approach to Dactylorhiza.

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Section: Methodsmentioning

confidence: 99%

Allozyme variation and genetic integrity of Dactylorhiza incarnata (Orchidaceae)

Pedersen

1998

Nordic Journal of Botany

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“…Diversity in genetic materials occurs due to variation in phenotypic appearance and genotypic background. Initially, the diversity of flax germplasm was assessed based on morphological parameters [ 6 , 7 ], and biochemical marker such as isozymes [ 8 , 9 ]. However, morphometric diversity often leads to false prediction as morphological characteristics are plant developmental stage dependent and environment sensitive [ 10 ].…”

Section: Introductionmentioning

confidence: 99%

Genetic diversity analysis of a flax (Linum usitatissimum L.) global collection

2020

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Background A sustainable breeding program requires a minimum level of germplasm diversity to provide varied options for the selection of new breeding lines. To maximize genetic gain of the North Dakota State University (NDSU) flax breeding program, we aimed to increase the genetic diversity of its parental stocks by incorporating diverse genotypes. For this purpose, we analyzed the genetic diversity, linkage disequilibrium, and population sub-structure of 350 globally-distributed flax genotypes with 6200 SNP markers. Results All the genotypes tested clustered into seven sub-populations (P1 to P7) based on the admixture model and the output of neighbor-joining (NJ) tree analysis and principal coordinate analysis were in line with that of structure analysis. The largest sub-population separation arose from a cluster of NDSU/American genotypes with Turkish and Asian genotypes. All sub-populations showed moderate genetic diversity (average H = 0.22 and I = 0.34). The pairwise F st comparison revealed a great degree of divergence ( F st > 0.25) between most of the combinations. A whole collection mantel test showed significant positive correlation (r = 0.30 and p < 0.01) between genetic and geographic distances, whereas it was non-significant for all sub-populations except P4 and P5 (r = 0.251, 0.349 respectively and p < 0.05). In the entire collection, the mean linkage disequilibrium was 0.03 and it decayed to its half maximum within < 21 kb distance. Conclusions To maximize genetic gain, hybridization between NDSU stock (P5) and Asian individuals (P6) are potentially the best option as genetic differentiation between them is highest ( F st > 0.50). In contrast, low genetic differentiation between P5 and P2 may enhance the accumulation of favorable alleles for oil and fiber upon crossing to develop dual purpose varieties. As each sub-population consists of many genotypes, a Neighbor-Joining tree and kinship matrix assist to identify distantly related genotypes. These results also inform genotyping decisions for future association mapping studies to ensure the identification of a sufficient number of molecular markers to tag all linkage blocks.

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“…Initial diversity assessments in flax were carried out using morphological parameters [9-12] and isozymes [13,14]. In recent years, molecular marker systems such as randomly amplified polymorphic DNA (RAPD), amplified fragment length polymorphism (AFLP), inter-simple sequence repeat (ISSR), simple sequence repeat (SSR) and inter-retrotransposon amplified polymorphism (IRAP) have been used to measure genetic variation and relationships in cultivars and landraces of flax [15-29].…”

Section: Introductionmentioning

confidence: 99%

Genetic characterization of a core collection of flax (Linum usitatissimum L.) suitable for association mapping studies and evidence of divergent selection between fiber and linseed types

et al. 2013

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BackgroundFlax is valued for its fiber, seed oil and nutraceuticals. Recently, the fiber industry has invested in the development of products made from linseed stems, making it a dual purpose crop. Simultaneous targeting of genomic regions controlling stem fiber and seed quality traits could enable the development of dual purpose cultivars. However, the genetic diversity, population structure and linkage disequilibrium (LD) patterns necessary for association mapping (AM) have not yet been assessed in flax because genomic resources have only recently been developed. We characterized 407 globally distributed flax accessions using 448 microsatellite markers. The data was analyzed to assess the suitability of this core collection for AM. Genomic scans to identify candidate genes selected during the divergent breeding process of fiber flax and linseed were conducted using the whole genome shotgun sequence of flax.ResultsCombined genetic structure analysis assigned all accessions to two major groups with six sub-groups. Population differentiation was weak between the major groups (FST = 0.094) and for most of the pairwise comparisons among sub-groups. The molecular coancestry analysis indicated weak relatedness (mean = 0.287) for most individual pairs. Abundant genetic diversity was observed in the total panel (5.32 alleles per locus), and some sub-groups showed a high proportion of private alleles. The average genome-wide LD (r2) was 0.036, with a relatively fast decay of 1.5 cM. Genomic scans between fiber flax and linseed identified candidate genes involved in cell-wall biogenesis/modification, xylem identity and fatty acid biosynthesis congruent with genes previously identified in flax and other plant species.ConclusionsBased on the abundant genetic diversity, weak population structure and relatedness and relatively fast LD decay, we concluded that this core collection is suitable for AM studies targeting multiple agronomic and quality traits aiming at the improvement of flax as a true dual purpose crop. Our genomic scans provide the first insights into candidate regions affected by divergent selection in flax. In combination with AM, genomic scans have the ability to increase the power to detect loci influencing complex traits.

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Isozyme relative mobility (R m ) changes related to leaf position; apparently smoothR m trends and some implications

Cited by 6 publications

References 21 publications

Allozyme variation and genetic integrity of Dactylorhiza incarnata (Orchidaceae)

Allozyme variation and genetic integrity of Dactylorhiza incarnata (Orchidaceae)

Genetic diversity analysis of a flax (Linum usitatissimum L.) global collection

Genetic characterization of a core collection of flax (Linum usitatissimum L.) suitable for association mapping studies and evidence of divergent selection between fiber and linseed types

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