Isozyme variation and heterozygosity in Pinus halepensis L.

Loukas, M.; Vergini, Y.; Krimbas, C. B.

doi:10.1007/bf00484442

Cited by 17 publications

(11 citation statements)

References 19 publications

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“…The few but distantly related diploid taxa which have been examined to date display the products of only a single hexokinase locus: Citrus and Poncirus (Torres etal. 1985); Salicornia europaea and S. ramosissima (Jefferies and Gottlieb 1982); Pinus halepensis (Loukas et al 1983); and notably the more closely related (to maize) diploids within the wheat genera Triticum and A egilops (Brody and Mendlinger 1980). In these studies, the hexokinase locus was either monomorphic or was not investigated genetically.…”

Section: Discussionmentioning

confidence: 99%

Duplicated chromosome segments in maize (Zea mays L.): further evidence from hexokinase isozymes

Wendel

Stuber

Edwards

et al. 1986

Theoret. Appl. Genetics

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The genetic control of hexokinase isozymes (ATP: d-hexose-6-phosphotransferase, E.C. 2.7.7.1, HEX) in maize (Zea mays L.) was studied by starch gel electrophoresis. Genetic analysis of a large number of inbred lines and crosses indicates that the major isozymes observed are encoded by two nuclear loci, designated Hexl and Hex2. Five active allozymes and one null variant are associated with Hexl, while Hex2 has nine active alleles in addition to a null variant. Alleles at both loci govern the presence of single bands, with no intragenic or intergenic heteromers visible, suggesting that maize HEX's are active as monomers. Organelle preparations demonstrate that the products of both loci are cytosolic. All alleles, including the nulls, segregate normally in crosses. Vigorous and fertile plants were synthesized that were homozygous for null alleles at both loci, suggesting that other hexosephosphorylating enzymes exist in maize that are undetected with our assay conditions. Linkage analyses and crosses with B-A translocation stocks place Hexl on the short arm of chromosome 3, 27 centimorgans from Pgd2 (phosphogluconate dehydrogenase) and Hex2 on the long arm of chromosome 6, approximately 45 centimorgans from Pgdl. It is suggested that the parallel linkages among these two pairs of duplicated genes reflects an evolutionary history involving chromosome segment duplication or polyploidy. d-hexose-6-phosphotransferase, E.C. 2.7.7.1, flEX) in maize (Zea mays L.) was studied by starch gel electrophoresis. Genetic analysis of a large number of inbred lines and crosses indicates that the major isozymes observed are encoded by two nuclear loci, designated Hexl and Hex2. Five active allozymes and one null variant are associated with Hexl, while Hex2 has nine active alleles in addition to a null variant. Alleles at both loci govern the presence of single bands, with no intragenic or intergenic heteromers visible, suggesting that maize HEX's are active as monomers. Organelle preparations demonstrate that the products of both loci are cytosolic. All alleles, including the nulls, segregate normally in crosses. Vigorous and fertile plants were synthesized that were homozygous for null alleles at both loci, suggesting that other hexosephosphorylating enzymes exist in maize that are undetected with our assay conditions. Linkage analyses and crosses with B-A translocation stocks place Hexl on the short arm of chromosome 3, 27 centimorgans from Pgd2 (phosphogluconate dehydrogenase) and Hex2 on the long arm of chromosome 6, approximately 45 centimorgans from Pgdl. It is suggested that the parallel linkages among these two pairs of duplicated genes reflects an evolutionary history involving chromosome segment duplication or polyploidy.

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Section: Discussionmentioning

confidence: 99%

Duplicated chromosome segments in maize (Zea mays L.): further evidence from hexokinase isozymes

Wendel

Stuber

Edwards

et al. 1986

Theoret. Appl. Genetics

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“…These differences may be due to the natural history of each population or to the exploitation of each area. In studies with Pinus, the genetic diversity was 0.179 for Pinus halepensis (Loukas et al, 1983) and 0.146 for Pinus rigida (Guries and Ledig, 1982). These data show that the genetic diversity values differ for various tree species, and that there is no pattern for species with similar ecological characteristics.…”

Section: Genetic Diversity and Structurementioning

confidence: 82%

Naturally fragmented but not genetically isolated populations of Podocarpus sellowii Klotzsch (Podocarpaceae) in southeast Brazil

Gonçalves¹,

Vieira

Carvalho

2016

Genet. Mol. Res.

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ABSTRACT. In southeastern Brazil, the majority of the riparian ecosystems are fragmented and degraded mainly due to human activities. The perennial gymnosperm Podocarpus sellowii Klotzch is a typical tree species from a gallery forest in the rupestrian area. Ten alloenzymatic loci were used to estimate the allelic frequency of 232 individuals distributed in eight subpopulations naturally divided by rock outcrops. The results indicated high genetic variability for the species in all subpopulations, with H O varying from 0.593 to 0.658, and H E , from 0.484 to 0.502. No endogamy was observed within (f = -0.292) and for the population set (f = -0.264). Genetic divergence of the species between subpopulations was 2.1%. Historic gene flow was low between subpopulations located in different water streams, corroborating the positive and significant correlation between genetic and geographical distance (r m = 0.496, P = 0.022). Co-ancestry 2 F.R. Gonçalves et al. Genetics and Molecular Research 15 (4): gmr.15048871 revealed that only population A presents continuous distribution of the genotypes up to 94 m. Sp statistics did not indicate significant spatial genetic structure in the populations. In all the subpopulations, values of effective sizes were higher than the numbers of sampled individuals. The balance between mutation and drift was not verified, indicating the occurrence of a recent population bottleneck. These data can be used to determine the most effective strategies for the genetic conservation of this species.

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“…ME-2 was found to be polymorphic whereas remaining three loci were monomorphic for all accessions of A. falcata. In Pinushalepensis [23], this enzyme is expressed by one locus only.…”

Section: Discussionmentioning

confidence: 99%

Isozymatic Characterization of Accessions of Arundinaria falcata (Nees)

Tiwari

Bakshi

2015

Forest Res

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Bamboos are arborescent grasses belonging to the family Poaceae. To study the genetics of bamboo specially, one has to face enormous difficulties such as rare flowering and we cannot make hybridizations as easily as like other plant taxa. Unlike other tropical bamboos, studies on hill bamboos are scarce. Arundinaria falcata, an important hill bamboo, acts as soil stabilizer in hilly terrain. This study assessed the genetic diversity of 10 accessions of A. falcata collected from different localities of Garhwal Himalayas (India) and established at Hill bamboo Germplasm at Khirsu (India), using isozyme marker with four enzyme system (peroxidase, esterase, malate dehydrogenase and malic enzyme). Isozymatic analyses were performed with polyacrylamide gels (one system), bands were scored as binary data. Cluster analyses were conducted, using Jaccard´s similarity coefficient and UPGMA method. Very high degree of similarity was reported i.e. 63-94% among different accessions. Dendrogram revealed two major clusters with three (A8-A10) and seven (A1-A7) accessions respectively. The results obtained inferred low genetic diversity in the species and urgent need of the in situ conservation of the natural genetic resources of the A. falcata species.

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Isozyme variation and heterozygosity in Pinus halepensis L.

Cited by 17 publications

References 19 publications

Duplicated chromosome segments in maize (Zea mays L.): further evidence from hexokinase isozymes

Duplicated chromosome segments in maize (Zea mays L.): further evidence from hexokinase isozymes

Naturally fragmented but not genetically isolated populations of Podocarpus sellowii Klotzsch (Podocarpaceae) in southeast Brazil

Isozymatic Characterization of Accessions of Arundinaria falcata (Nees)

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