Genome Size Variation and Basic Chromosome Number in Pearl Millet and Fourteen Related Pennisetum Species

Martel, Evelyne; Nay, D. De; Siljak-Yakoviev, S.; Brown, Spencer C.; Sarr, Amadou

doi:10.1093/oxfordjournals.jhered.a023072

Cited by 122 publications

(100 citation statements)

References 23 publications

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“…Such variations are similar to other findings in our earlier work on mangroves (Das et al 1996, Basak et al 1998, Das et al 2001, Jena et al 2002. The diversity of DNA amount has often been attributed to loss or addition of highly repetitive DNA sequences rather than the AT-or GC-reach sequences in a genome (Martel et al 1997) which after a certain level got stabilized during micro-evolution and gradual selection (Price et al 1980). Such interspecific variations in DNA amount were not exceptional in angiosperm species (Laurie and Bennett 1985, Rayburn et al 1989, Tito et al 1991.…”

Section: Nuclear Dna Analysis Genome Size and Invsupporting

confidence: 90%

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Variation in Chromosome Number, Karyotype and Nuclear DNA Content of Five Species of Indian Typhonium Schott. (Araceae)-A Medicinally Important Plant

et al. 2006

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Summary Detailed karyotype analysis of somatic chromosomes in 5 species of Typhonium Schott. of the family Araceae was carried out for the first time. The chromosome number varied from 2nϭ16 in T. flagelliforme to 2nϭ52 in T. diversifollium. Chromosome number 2nϭ18 and 2nϭ26 in T. trilobatum and T. roxburghii respectively suggest formation of anueploids during speciation. The asymmetric karyotype revealed structural alterations with 2 distinct types of chromosomes (long and very short types) as evident in different species of Typhonium. Significant variations in chromosome size were observed among the studied species. TF% revealed sub-metacentric long chromosomes in T. flagelliforme (TF value, 33%) and metacentric short chromosomes in T. diversifolium (TF value, 41%). Average chromosome length varied from 2.03 mm in T. diversifolium, a high altitude species (5000-7000 ft), to 8.68 mm in T. flagelliforme, a low land species (70-250 ft). Significant variations were observed in Interphase Nuclear Volume (INV) which varied from 142.05 mm 3 in T. trilobatum to 335.02 mm 3 in T. flagelliforme; nuclear DNA content varied significantly from 0.199 pg in T. diversifolium to 0.833 pg in T. flagelliforme.Key words Chromosome number, Karyotype, Nuclear DNA, Typhonium.The genus Typhonium Schott. of the family Araceae comprises about 79 species distributed mostly in the south-east Asia and north-east Australia (Hay 1993). In India and Indo-Malesian region, the genus is represented by 16 species (Santapau and Henry 1973). While Typhonium divaricatum (Linn.) Decne occurs mainly in the Penninsular India, T. trilobatum (Linn.) Schott. and T. flagelliforme Decne are the commonly found species in Bengal, Bihar, Orissa and Coromandel coast.In T. trilobatum, somatic chromosomes 2nϭ18 was reported (Sharma and Mukhopadhyay 1965) and 2nϭ26 (Simmonds 1954) were reported with distinctly different morphological characteristics among the ecotypes. Taxonomical grouping of some members of Araceae i.e. genus Sauromatum and Lazarum into Typhonium (Hay 1993) was of interest to us. However such groups based on chromosomal parameters, their karyotypes are not available. This paper deals with detailed investigations on chromosome number their karyotype, interphase nuclear volume (INV) and in situ nuclear DNA content in 5 Indian species of Typhonium may provide insight into chromosome behavior and genomic characteristics during the evolution and speciation in this genus. Materials and methods PlantsTubers of 5 species of Typhonium were collected from varied ecological conditions and main-

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Section: Nuclear Dna Analysis Genome Size and Invsupporting

confidence: 90%

“…This diversity in DNA amount had often been attributed to loss or addition of highly repetitive DNA sequences rather than the AT-or GC-rich sequences in a genome (Martel et al 1997) that reached a certain level and became stabilized during micro-evolution and gradual selection (Price et al 1980).…”

Section: Nuclear Dna Analysis Genome Size and Invmentioning

confidence: 99%

Variation in Chromosome Number, Karyotype and Nuclear DNA Content of Five Species of Indian Typhonium Schott. (Araceae)-A Medicinally Important Plant

et al. 2006

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“…The millet chromosomes appeared to adapt the oat background in these hybrids. Since the millet genome (2450 Mb) (Martel et al 1997) is significantly smaller than the oat genome (11,300 Mb), our data suggest that the millet centromeres expanded to adapt to the overall larger genome environment. Interestingly, the centromeres of millet chromosomes contain large amounts of satellite repeats (Ishii et al 2013) and may lack active genes, which is favorable for centromere expansion.…”

Section: Transcription and Neocentromere Establishmentmentioning

confidence: 80%

Maize centromeres expand and adopt a uniform size in the genetic background of oat

Wang

Zhang

et al. 2013

Genome Res.

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Most existing centromeres may have originated as neocentromeres that activated de novo from noncentromeric regions. However, the evolutionary path from a neocentromere to a mature centromere has been elusive. Here we analyzed the centromeres of nine chromosomes that were transferred from maize into oat as the result of an inter-species cross. Centromere size and location were assayed by chromatin immunoprecipitation for the histone variant CENH3, which is a defining feature of functional centromeres. Two isolates of maize chromosome 3 proved to contain neocentromeres in the sense that they had moved from the original site, whereas the remaining seven centromeres (1, 2, 5, 6, 8, 9, and 10) were retained in the same area in both species. In all cases, the CENH3-binding domains were dramatically expanded to encompass a larger area in the oat background (∼3.6 Mb) than the average centromere size in maize (∼1.8 Mb). The expansion of maize centromeres appeared to be restricted by the transcription of genes located in regions flanking the original centromeres. These results provide evidence that (1) centromere size is regulated; (2) centromere sizes tend to be uniform within a species regardless of chromosome size or origin of the centromere; and (3) neocentromeres emerge and expand preferentially in gene-poor regions. Our results suggest that centromere size expansion may be a key factor in the survival of neocentric chromosomes in natural populations.

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“…Sporadic evidences for closeness of P. glaucum with P. squamulatum have been gathered by reports on crossability between the two species (Dujardin and Hanna 1983, Kaushal et al 2007, Marchais and Tostain 1997, DNA content trends in Pennisetum species (Martel et al 1997), isozyme studies (Kaushal et al 1997), internal transcribed spacer (ITS) sequences (Martel et al 2004), and crossability with other xϭ7 species such as P. purpureum (Hanna 1990).…”

mentioning

confidence: 99%

Sequential Reduction of Pennisetum squamulatum Genome Complement in P. glaucum (2n=28)*P. squamulatum (2n=56) Hybrids and their Progenies Revealed its Octoploid Status

et al. 2008

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Summary P. squamulatum Fresen. is an important Pennisetum species by virtue of its characters, such as, apomixis, perenniality and stress tolerance, which can be utilized for pearl millet improvement. This species is hitherto believed to be 2nϭ6xϭ54, however, recent reports of 2nϭ56 cytotypes rendered to recheck the ploidy status. In present study, meiotic system of F 1 and advanced hybrids, such as F 2 , F 1 sibs, and BC 1 , involving P. squamulatum (2nϭ56) and P. glaucum (2x and 4x) were investigated following a scheme to sequentially reduce P. squamulatum chromosome complement to half, in order to determine its ploidy. The cytological results indicating high bivalent frequencies in these generations confirmed octoploid (instead of 6x) nature of P. squamulatum, alongwith its basic chromosome number as 7 (similar to pearl millet) with its allo-octoploid (or auto-allo octoploid) status. On the basis of cytogenetical studies viz. crossability, DNA content, genetic relatedness and cytology of advanced hybrids, placement of P. squamulatum in secondary gene pool of pearl millet is supported.

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Genome Size Variation and Basic Chromosome Number in Pearl Millet and Fourteen Related Pennisetum Species

Cited by 122 publications

References 23 publications

Variation in Chromosome Number, Karyotype and Nuclear DNA Content of Five Species of Indian Typhonium Schott. (Araceae)-A Medicinally Important Plant

Variation in Chromosome Number, Karyotype and Nuclear DNA Content of Five Species of Indian Typhonium Schott. (Araceae)-A Medicinally Important Plant

Maize centromeres expand and adopt a uniform size in the genetic background of oat

Sequential Reduction of Pennisetum squamulatum Genome Complement in P. glaucum (2n=28)*P. squamulatum (2n=56) Hybrids and their Progenies Revealed its Octoploid Status

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