Genome Size Variation in the Aloaceae, an Angiosperm Family Displaying Karyotypic Orthoselection

Brandham, P. E.; Doherty, Mary Jane

doi:10.1006/anbo.1998.0742

Cited by 59 publications

(56 citation statements)

References 16 publications

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“…Such observations have been seen in other lineages of the monocots, such as Commelinaceae, in which Robertsonian changes are well known (Jones 1998). A similar pattern is found in Asphodelaceae, in which DNA amounts vary twofold just among diploid species of Aloe with the same number of chromosomes (Brandham and Doherty 1998). Our understanding of other genera with numerous existing DNA content measurements (e.g., Allium, Ohri et a!.…”

Section: Mitochondrial Evolution and Telomere Composition Insupporting

confidence: 64%

Phylogeny, Genome Size, and Chromosome Evolution of Asparagales

Pires¹,

Maureira²,

Givnish³

et al. 2006

aliso

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Asparagales are a diverse monophyletic order that has numerous species (ca. 50% of monocots) including important crop plants such as Allium, Asparagus, and Vanilla, and a host of ornamentals such as irises, hyacinths, and orchids. Historically, Asparagales have been of interest partly because of their fascinating chromosomal evolution. We examine the evolutionary dynamics of Asparagales genomes in an updated phylogenetic framework that combines analyses of seven gene regions (atpl, atpB, matK, ndhF, rbcL, trnL intron, and trnL-F intergenic spacer) for 79 taxa of Asparagales and outgroups. Asparagales genomes are evolutionarily labile for many characters, including chromosome number and genome size. The history and causes of variation in chromosome number and genome size remain unclear, primarily because of the lack of data in small clades in the phylogenetic tree and the lack of comparative genetic maps, apart from Allium and Asparagus. Genomic tools such as bacterial artificial chromosome (BAC) libraries should be developed, as both molecular cytogenetic markers and a source of nuclear genes that can be widely used by evolutionary biologists and plant breeders alike to decipher mechanisms of chromosomal evolution.

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Section: Mitochondrial Evolution and Telomere Composition Insupporting

confidence: 64%

Phylogeny, Genome Size, and Chromosome Evolution of Asparagales

Pires¹,

Maureira²,

Givnish³

et al. 2006

aliso

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“…Similar studies in other plant groups have shown DNA content to vary up to 200% without alterations of the basic karyotype (Brandham and Doherty, 1998), and this sort of variation in DNA content is difficult to assess or even identify using a microscope. Preliminary ploidy analysis of New Zealand populations of H. pilosella using flow cytometry detected some plants with DNA content intermediate in amount between that observed from tetraploid and pentaploid individuals.…”

Section: Introductionmentioning

confidence: 81%

Interspecific hybridization among Hieracium species in New Zealand: evidence from flow cytometry

et al. 2004

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Hieracium pilosella (Asteraceae) was accidentally introduced to New Zealand about 100 years ago. Since then it has become an aggressive weed, and an unexpected degree of genetic and genome size variation has been detected; features that might result from interspecies hybridization. We investigated the possibility that H. pilosella has hybridized with related taxa. Of the four other subgenus Pilosella species introduced to New Zealand, H. praealtum is the most abundant and, on morphological and distributional evidence, most likely to be the other parent. Flow cytometry was used to estimate relative genome size for 156 Hieracium plants collected from the wild. Plants assigned to either parental or hybrid morphotypes were found to comprise tetraploid and pentaploid individuals using genome size measurements, and this was confirmed with direct mitotic chromosome counts for a subset of plants. The haploid DNA content of H. praealtum was approximately 22% larger than that of H. pilosella.Putative hybrids that were tetraploid had mean genome sizes equivalent to two H. pilosella and two H. praealtum haploid chromosome sets, implying they were hybrids arising from the fertilization of two reduced gametes. Similar results were obtained from tetraploid hybrids produced by controlled pollination. However, the majority of field hybrids were pentaploid with a genome size equivalent to four H. pilosella and one H. praealtum haploid chromosome sets. We infer that these are not first-generation hybrids but represent successful backcrossing with H. pilosella and/or hybrid-hybrid crossing, and that sexual tetraploid hybrids have been the parents. We note that populations putatively of H. pilosella often comprise apomictic pentaploid hybrids. Significantly, our data indicate the emergence of sexual hybrids that provide further opportunity for gene flow among taxa in this complex.

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“…In Aloe genus tetraploidy is quite rare (11,18). Most species of Aloe are diploid (2n = 14) although a very few are tetraploid including A. Cremnophila and A. Inermis (2n = 28) reported from natural populations of Somalia (9). Occurrence of triploidy in Aloe has also been reported.…”

Section: Discussionmentioning

confidence: 98%

“…Recently, cytogenetical studies have been used as taxonomic information besides biochemical, molecular, morphological and anatomical studies. Earlier studies suggested that Aloe has great potential of chromosomal stability due to the presence of bimodal constant karyotype (9)(10)(11). Determination of the chromosomal alterations and DNA variation have been proposed, usinf karyotype analysis, (12) and these variants have been used to evaluate the plant species (13).…”

Section: Introductionmentioning

confidence: 99%

Karyotypic Variation of the Aloe vera L. and Aloe littoralis Baker in Iran

Nejatzadeh-Barandozi

Akbari

2013

Iran J Biotech

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Background:We describe karyotypic variations and the in vitro methods for plant propagation and conservation as well as detailed chromosomal analysis of (Aloe vera L.) and Aloe littoralis from Iran during flowering stage. Objectives: This karyotypic was discovered because of a difference in the position of the chromosome and due to genomic differentiation in domesticated populations of the Iranian species. We show that highly conserved ortho selected karyotype in (Aloe vera L.) both in in vivo and in vitro grown cultivars. Materials and Methods: Cytological investigation of Aloe littoralis in vitro grown plants revealed its tetraploid nature. Chromosome behaviors in miosis cell division were studied in one hundred cells and the populations and the parameters such as number and type of formed chiasmas were recorded. Results: Despite the large size of the chromosomes, the most portions of the observed chiasmata were one chiasma per pairs of homologes. A population of Aloe littoralis showed high level of four chiasmata. The percentage of pollen viability is high in both (Aloe vera L.) and Aloe littoralis, yet the flowers failed to form fruits. Conclusions: This finding, in combination with regional differences in the frequency of the karyotype, has important values for future studies using Aloe spices.

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Genome Size Variation in the Aloaceae, an Angiosperm Family Displaying Karyotypic Orthoselection

Cited by 59 publications

References 16 publications

Phylogeny, Genome Size, and Chromosome Evolution of Asparagales

Phylogeny, Genome Size, and Chromosome Evolution of Asparagales

Interspecific hybridization among Hieracium species in New Zealand: evidence from flow cytometry

Karyotypic Variation of the Aloe vera L. and Aloe littoralis Baker in Iran

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