DNA sequence organization in the genomes of three related millet plant species

Sivaraman, Lakshmi; Gupta, Vidya S.; Ranjekar, P. K.

doi:10.1007/bf00027131

Cited by 10 publications

(3 citation statements)

References 37 publications

(39 reference statements)

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“…Molecular genetics. DNA of foxtail millet has several distinguishing features: low nuclear DNA content (haploid, Cvalue, 1C:0.82 pg), low proportion of repetitive DNA (30%), and the presence of a high-melting point component (4.7 to 6.7% of the genome) (Lakshmi and Ranjekar 1984;Siva Raman et al 1986). The total proportion of repetitive DNA was the lowest value in the Poaceae family at the time it was reported (Lakshmi and Ranjekar 1984).…”

Section: Geneticsmentioning

confidence: 99%

“…It has been suggested that this high thermal stability in foxtail millet may indicate very little to no base sequence mismatch, a rare observation, or that this stability maintains internal homogeneity by ''crossover'' fixation (Smith 1976). A major part of the foxtail millet genome (85%) consists only of long interspersed repeated DNA sequences (greater than 1.5 kb; Siva Raman et al 1986). These long sequences can maintain genome size by slow rates of turnover, in which repeated DNA sequences are not subjected to mutations, deletions, or base substitutions at a very rapid rate (Flavell 1980;Siva Raman et al 1986).…”

Section: Geneticsmentioning

confidence: 99%

“…A major part of the foxtail millet genome (85%) consists only of long interspersed repeated DNA sequences (greater than 1.5 kb; Siva Raman et al 1986). These long sequences can maintain genome size by slow rates of turnover, in which repeated DNA sequences are not subjected to mutations, deletions, or base substitutions at a very rapid rate (Flavell 1980;Siva Raman et al 1986). The significance of genome size in phylogeny is not understood, the so-called C-value paradox (Orgel and Crick 1980).…”

Section: Geneticsmentioning

confidence: 99%

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The foxtail (Setaria) species-group

2003

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The weedy Setaria species (giant, green, yellow, knotroot, and bristly foxtail) compose one of the worst weed groups interfering with world agriculture and in other disturbed and managed habitats. These species, together with their crop counterparts (foxtail millet, korali), form the foxtail species-group (spp.-gp). Five successive waves of Setaria spp. invasion from preagricultural times to the present have resulted in widespread infestation of the disturbed, arable, temperate regions of the earth. These invasions have resulted in considerable economic and environmental costs. The success of the Setaria spp.-gp is because of their intimate evolutionary relationship with humans, disturbance, agriculture, and land management. The ability to adapt rapidly to local conditions is the hallmark of this weedy group. Genotypic and phenotypic biodiversity provides this spp.-gp with traits that allow it to invade, colonize, adapt to, and endure in a wide range of habitats around the world. The phenotypic life-history traits important to the success of weedy Setaria spp. begin with the induction of dormancy in seed during embryogenesis. The formation of long-lived, heterogeneous seed pools in the soil is the inevitable consequence of the dormant seed rain. In soil seed pools, after-ripening, the occurrence and timing of seedling emergence, and the induction of secondary (summer) dormancy are regulated by seasonally and diurnally varying soil oxygen, water, and temperature signals. Precise and variable timing of seedling emergence ensures Setaria a dominant place in disturbed and managed communities during the growth and reproductive phases that follow. Once established in a community, phenotypic plasticity inherent in an individual weedy Setaria sp. allows it to maximize its growth, form, and reproduction to the specific local conditions it encounters, including competitive interactions with neighbors. Traits controlling the plastic development of plant architecture include the ability to form one or more tillering shoots whose stature and number are precisely sized to local conditions. A complex pattern of branching, from plant to spikelet, provides diverse microenvironments within which different levels of dormancy are induced in individual seeds on a panicle and among panicles on a common plant. Traits for adaptation to stress in weedy Setaria spp. include tolerance to many inhibitory chemicals (e.g., herbicides, salt), mechanical damage, and drought. Genetic traits such as self-pollination and small genome size contribute to a highly diverse collection of locally adapted genotypes and phenotypes ready to exploit any opportunities provided by a cropping system. Self-pollinating Setaria spp. exist in wild, weed, and crop variants, an ideal genetic condition ensuring both long-term stability and novelty. Weedy Setaria spp. populations have low to exceedingly low amounts of total genetic variation, unusually low intrapopulation genetic diversity, and unusually high genetic diversity between populations compared with an aver...

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Section: Geneticsmentioning

confidence: 99%