Feulgen microspectrophotometric estimation of nuclear DNA of species and varieties of three different genera of Marantaceae

Abstract: The DNA amount in the unreplicated haploid nucleus of an organism is known as its C-value. C-values differ about 1000-fold among angiosperms and are characteristic of taxa. The data are used in many biological fields, so they should be easily available. Values for 2802 angiosperm species (1%) were estimated during 1950–1997, and five collected lists of C-values were published for reference purposes during 1976–1997. Numbers of new angiosperm C-values published recently remained high, necessitating a further supplementary list. This paper lists DNA C-values for 807 angiosperm species from 70 original sources, including 520 (75.2%) from sources published after 1996, and 691 for species not included in any of the previous five lists. There is a continuing need to estimate accurate DNA C-values for plant taxa, as shown in a workshop on this biodiversity topic sponsored by Annals of Botany and held at Kew in 1997. Its key aim was to identify major gaps in our knowledge of plant DNA amounts and to recommend targets and priorities for new work to fill them. A target of estimating first C-values for the next 1% of angiosperm species in 5 years was set. The proportion of such C-values in the present work (85.6%) is very high; and the number being published (approx. 220 per annum) has never been exceeded. In 1997, C-values were still unknown for most (68%) families, so a target of complete coverage was set. This paper includes first C-values for 12 families, but as less than 2% of such values listed here targeted new families, the need to improve familial representation remains.

Abstract: Extensive karyotype analysis including determination of somatic chromosome number, total chromosome length and volume and estimation of 4C DNA amount were carried out on 9 different cultivars of ginger (Zingiber officinale Rose.) for the first time. A significant variation in nuclear DNA amount was recorded at the cultivar level. The 4C DNA amount varied from 19.663-24.102 pg in the cultivars studied. The correlation coefficient studies showed that the 4C DNA content and genomic chromosome volume were interdependent. The structural alteration of chromosomes as well as loss or addition of highly repetitive sequences in the genome showed variation in the DNA amount at cultivar level, but a marginal variation in nuclear DNA content at the cultivar level indicated a close relationship between them.

Abstract: Investigation on karyotype, 4C nuclear DNA amount and interphase nuclear volume (INV) of different HimalayanBupleurum species belonging toUmbelliferae revealed genetic differentiation. Numerical and structural alternation of chromosomes in interspecific level were manifested in their statistically significant altered species specific 4C nuclear DNA content. Somatic chromosome number ranged between 2n = 14 and 2n = 16.B. himalayense was reported for the first time having 2n = 16 chromosomes. Correlation coefficient among the various chromosomal and nuclear parameters showed no significant progressive or regressive interdependence except in between INV and nuclear DNA amount. Critical differences between 4C DNA content showed interspecific variation.

Abstract: Extensive karyological analysis including determination of somatic chromosome number, total chromosome length and volume and estimation of 4C DNA amount were carried out on 8 different varieties of Coriandrum sativum L. A significant variation in nuclear DNA amount was recorded in the varietal level. The structural alteration of chromosome as well as loss or addition of highly repetitive sequences in the genome have played a vital role in intervarietal DNA variation. The absence of wide differences in nuclear DNA content in the varietal level indicate a close relationship between them.

Abstract: A detailed karyotypic analysis and cytophotometric estimation of 4C DNA amount was carried out in six species of the subtribe Carinae of Umbelliferae. Intergeneric and interspecific chromosome number viz., 2n=14, 18, 20, 22 were varied in the subtribe level. Critical analysis of chromosome morphology revealed the structural alteration of chromosomes along with their changed DNA amount. Significant variation of DNA amount having numerical, gross or minor chromosomal alteration leads to the genetic drift in between the species of the subtribe suggesting the compromise between the structural and biochemical changes of the genome during macro- and micro-evolution.

Abstract: Natural selection operating within genomes will inevitably result in the appearance of DNAs with no phenotypic expression whose only ‘function’ is survival within genomes. Prokaryotic transposable elements and eukaryotic middle-repetitive sequences can be seen as such DNAs, and thus no phenotypic or evolutionary function need be assigned to them.

Abstract: Eight classes of human leukocyte interferon (LeIFN) cDNA clones have been identified in a cDNA library prepared from a myeloblastoid cell line. The nucleotide sequences demonstrate that the multiple human LeIFN genes code for a family of homologous, yet distinct proteins. One of the cDNA clones may have been derived from the transcription of a LeIFN pseudogene.

Abstract: DNA endoreduplication and related phenomena (such as endomitosis, polyteny, nuclear restitution and somatic polyploidy in general) are widespread over the animal and plant kingdoms, although they occur most frequently among insects and angiosperms1–3. The systematic restriction to certain phyla and species has been interpreted in terms of high genetic control of such events3, whereas the characteristic developmental pattern of various degrees of endopolyploidy has been considered as an expression of their functional role in differentiation and synthesising capacity of the cells2,4,5. Recently,however, any role of endoreduplication in cell differentiation has been questioned because of the existence of species apparently lacking endopolyploidy6. All previous discussions on endoreduplication, endopolyploidy and polyteny have, however, ignored the basic DNA contents of the species studied. We here report a relationship between the basic nuclear DNA content and the occurrence and degree of endopolyploidy. This strongly suggests that DNA endoreduplication can be regarded as an evolutionary alternative to the high nuclear DNA content that has been achieved in other species mainly by ‘saltatory replications’.

Abstract: The number and chromosomal locations of elements of the 412, copia and 297 dispersed repeated gene families differ extensively when the genomes of four D. melanogaster strains are compared. Differences among individuals from the same laboratory stock in the arrangement of these elements are also observed. In contrast to these polymorphisms, the structures of the elements themselves are closely conserved. Our results indicate that 412, copia and 297 are capable of evolutionarily rapid transpositions to new chromosomal sites.

Abstract: Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Range of Variability of DNA Content . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 DNA Variation in Higher Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Gymnosperms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Angiosperms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Mechanisms of Change in DNA Content . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Cellular and Organismic Correlations with DNA Content . . . . . . . . . . . . . . . . . . . . . . . . 40 Functions of DNA Sequences Duplicated or Deleted during Evolution . . . . . . . . . . . . . 41 Prospects for Future Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 Literature Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47