Chromosome Numbers in Astragalus and Oxytropis

Ledingham, George F.

doi:10.1139/g60-012

Cited by 39 publications

(21 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

Section: Resultsmentioning

confidence: 99%

“…LEDINGHAM (1960) found that the Astragalus species from the old world have a basic chromosome number of X = 8, while those from the new world have X = 11, 12 and 13. This report was substantiated by LEDINGHAM and REVER (1963). Chromosome counts, based on X = 8 have been reported in the vast majority of old world in Astragalus genus while counts based on base numbers X = 7 or X = 6 have been encountered in few species (MAASSOUMI 1987;BADR et al 1996;MALALLAH et al 2001;BADR and SHARAWY 2007).…”

Section: Resultsmentioning

confidence: 99%

“…An extensive number of cytological studies has been performed in Astragalus throughout the world, including Iran (LEDINGHAM 1960;LEDINGHAM and REVER 1963;MAASSOUMI 1987;BADR et al 1996;MALALLAH et al 2001;BADR and SHARAWY 2007;SHEIDAI et al 2009), reporting the basic chromosome numbers of x = 7, 8, 11-15 and diploid, tetraploid, hexaploid and octaploid levels for the genus. The present study reports somatic chromosome characteristics, including morphology and number of Astragalus effuses from Isfahan, Iran.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Karyotype analysis ofAstragalus effususBunge (Fabaceae)

2010

View full text Add to dashboard Cite

⎯ In this study, the karyotype analysis of Astragalus effusus Bunge species was studied using Image Analysis System. The protocol assayed consisted of the use of α-bromonaphthalene for pretreatment, Lewitsky solution for fi xation, 1N NaOH for hydrolysis and fi nally, aceto iron-hematoxylin for staining stage. The species' chromosome number was 2n = 4x = 32, chromosome lengths range from 1.57 to 2.99 µm and the length of the whole genome was 75.8 µm; also, the chromosome length and arm lengths showed this species was most likely natural autotetraploid and observed one pericentric inversion in chromosomes of the VIII group. Regarding the karyotypic symmetry, this species belongs to the 2A karyotypic symmetry class with a 7m + 2m sat + 7sm karyotype formula. Asymmetrical parameters emphasize on rather symmetry karyotype in this species. In this paper, we assess the karyotype of this species for the fi rst time.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Karyotype analysis ofAstragalus effususBunge (Fabaceae)

2010

View full text Add to dashboard Cite

show abstract

“…New World Astragalus species are almost exclusively aneuploids with a most frequent basic chromosome number n = 11, and polyploidy is virtually absent among them (reviewed in Spellenberg (1976) and Wojciechowski et al (1993)). The situation is markedly different in Old World species, where, besides the widespread diploid chromosome number 2n = 16, frequent counts of 2n = 32, 48, and 64 have been reported by cytological studies (Ledingham 1960;Ledingham and Rever 1963;Fedorov 1969;Philippov et al 2008;Masoud et al 2009). Ploidy levels might be phylogenetically determined, as observed by shared ploidy in closely related species.…”

Section: Introductionmentioning

confidence: 95%

Molecular evidence for reticulate speciation in Astragalus (Fabaceae) as revealed by a case study from sect. Dissitiflori

BarthaLászló

DragoşNicolae

Attila

et al. 2013

Botany

View full text Add to dashboard Cite

Although hybridization has long been recognized as a major force driving speciation in land plants, it has not yet been evidenced in Astragalus, the largest angiosperm genus. Here, we reveal the possible contribution of hybridization to speciation in Astragalus by employing cloning of the nrDNA ITS region and sampling three plastid regions (ycf1, ndhF-rpl32, and rpl32-trnL) in taxa belonging to sect. Dissitiflori. Phylogenetic network and tree analyses uncovered various levels of intra-individual and intraspecific polymorphism of ITS in most of the taxa investigated. Two distantly related ribotype groups were found to be shared by the closely related polyploids Astragalus pallescens M.Bieb., Astragalus peterfii Jáv., and Astragalus pseudoglaucus Klokov suggesting ancient hybridization followed by incomplete lineage sorting (i.e., shared ancestral polymorphism) in nrDNA ITS. Reticulation is also invoked as an underlying evolutionary process behind the statistically highly supported incongruent placement of A. pseudoglaucus and Astragalus vesicarius subsp. pastellianus (Pollini) Arcang. in nuclear versus plastid phylogenies. The phylogenetic results also shed light on taxonomic controversies in the section, such as the false synonimization of A. peterfii under A. vesicarius s.l. Our results provide evidence for the (at least past) existence of speciation processes driven by hybridization in Astragalus.Key words: hybridization, ycf1, nrDNA ITS cloning, allopolyploidy, reticulation.Résumé : Bien qu'on ait reconnu depuis longtemps l'hybridation comme force majeure soutenant la spéciation chez les plantes terrestres, on n'en pas encore la preuve chez les Astragalus spp, le plus important genre des angiospermes. On évoque ici la contribution possible de l'hybridation à la spéciation des Astragalus spp., en utilisant le clonage de la région ITS du nrADN et en échantillonnant trois régions plastidiques (ycf1, ndhF-rpl32 et rpl32-trnL) chez des taxons de la section Dissitiflori. Le réseau phylogénétique et trois analyses révèlent divers degrés de polymorphisme intra-individuel et intraspecifique de l'ITS, chez la plupart des taxons examinés. On a repéré deux groupes de ribotypes partagés par l'Astragalus pallescens M. Bieb., l'Astragalus peterfii Jáv., et l'Astragalus pseudoglaucus Klokov, des polyploïdes étroitement reliées, ce qui suggère d'anciennes hybridations suivies de sélections de lignées incomplètes (i. e. polymorphisme ancestral partagé) dans l'ITS nrADN. On évoque la réticulation comme processus évolutif sous-jacent, également à la source de la localisation incongrue, fortement supportée statistiquement, de l'A. pseudoglaucus et de l'Astragalus vesicarius subsp. pastellianus (Pollini) Arcang. dans les phylogénies nucléiques versus plastidiques. Les résultats phylogénétiques éclairent les controverses sur la section, tel la fausse synonymie de l'A. peterfii sous l'A. vesicarius s.l. Les résultats fournissent la preuve (du moins dans le passé) de l'existence de processus de spéciation activés par l'...

show abstract

“…Since then there have been many other studies counting chromosome numbers and identifying ploidy levels for both New and Old World Astragalus species (Löve 1954;Head 1957;Ledingham 1957Ledingham , 1960Turner and Fearing 1960;Ledingham and Rever 1963). According to the work of many contributors to the IOPB Chromosome Number Reports, edited by Löve (Cartier 1976;Dvorak and Dadakova 1978;Hindakova and Schwarzova 1978;Dawe and Murray 1981;Löve and Löve 1982;Aryavand 1983;Ashraf and Gohil 1986), as well as other studies (Maassoumi 1987(Maassoumi , 1989bSheidai et al 1996;Badr and Sharawy 2007;Martin et al 2008), most cytological studies in the genus have concentrated on chromosome counts.…”

Section: Introductionmentioning

confidence: 99%

An overview on cytogenetics of the genusAstragalussubgenusHypoglottis(Fabaceae)

Ranjbar

Mahmoudian

2015

Caryologia

View full text Add to dashboard Cite

This study reports the chromosome number and meiotic behavior of 24 populations belonging to 16 species of Astragalus sect. Malacothrix from Iran. Thirteen populations showed the diploid chromosome number 2n = 2x = 16; consistent with the proposed base number of x = 8 from ICPN. However, tri-, tetra-and hexaploids were also observed in the rest of the taxa. Although the species displayed regular bivalent pairing and chromosome segregation at meiosis, non-oriented bivalents, laggard chromosomes, precocious migration of chromosomes to the poles, micronuclei, multipolar meiocytes, desynapsis, chromosome stickiness, bridges, asynchronism and cytomixis were also determined as meiotic abnormalities. Evolution in chromosome numbers in taxa belonging to A. sect. Malacothrix along with six other sections which have been classified under A. subgen. Hypoglottis is also discussed.

show abstract

Chromosome Numbers in Astragalus and Oxytropis

Cited by 39 publications

References 10 publications

Karyotype analysis ofAstragalus effususBunge (Fabaceae)

Karyotype analysis ofAstragalus effususBunge (Fabaceae)

Molecular evidence for reticulate speciation in Astragalus (Fabaceae) as revealed by a case study from sect. Dissitiflori

An overview on cytogenetics of the genusAstragalussubgenusHypoglottis(Fabaceae)

Contact Info

Product

Resources

About