Journal ArticleDOI
Chromosome banding in evolutionary plant cytogenetics
U C Lavania,A K Sharma +1 more
- Vol. 92, Iss: 1, pp 51-79
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TLDR
The introduction of chromosome banding techniques for linear differentiation of chromosomes have allowed the identification of the heterochromatic segments on the chromosomes, which have been utilized for inter- and intra-species comparisons and the probable phylogenetic relationships in various plant taxa from Gymnosperms, Angiosperms have been suggested.Abstract:
The introduction of chromosome banding techniques for linear differentiation of chromosomes have allowed the identification of the heterochromatic segments on the chromosomes. These heterochromatic segments are primarily composed of repetitive DNA, which are discernible in the form of dark staining regions by Giemsa C band staining or exhibit enhanced or reduced fluorescent bands by Q banding techniques depending upon the particular type of DNA repetition. The analyses of banding patterns have allowed in plants, the identification of chromosomes or parts of chromosomes, which have been utilized for inter- and intra-species comparisons. Based on the information of banding patterns, amount and distribution of heterochromatic segments, coupled with karyotypic features and morphological similarities; the probable phylogenetic relationships in various plant taxa from Gymnosperms, Angiosperms (both dicots and monocots) have been suggested. The information on heterochromatin recognition have also been utilized in suggesting probable ancestry of polyploids and the trend of evolution in varietal differentiation and speciation. Analysing the data, a probable phylogenetic significance and the direction of change in heterochromatin evolution in plants is suggested.read more
Citations
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Journal ArticleDOI
Karyotype Analysis of Seven Varieties of Taro Colocasia esculenta (L.) Schott. from Bangladesh
TL;DR: Nuclear and chromosome characteristics of seven varieties of Colocasia esculenta were studied and revealed that somatic chromosome number was 28 in cytotype-1, 2, 5, 6 and 7; 42 in cytotyp-3 and 21 in cytotypes-4.
Journal ArticleDOI
Genetic variability in Lathyrus spp. as revealed by karyotype analysis.
TL;DR: The data allowed the differentiation of several accessions among sections Lathyrus, Linearicarpus and Clymenum in number of m chromosome, suggesting that section Lath Cyrus is not fully constant as has been postulated.
Journal ArticleDOI
Constitutive Heterochromatin during Meiosis and Mitosis in Allium cepa and Rhoeo discolor
TL;DR: The staining and structural hehaviour of heterochromatin during meiotic division was compared with that in mitosis in Allium cepa and Rhoeo discolor and indicates the difference in its behaviour during pairing.
Book ChapterDOI
C-banding in vicia species
TL;DR: Using Leishmans stain for C-banding, the authors indicate the use of this approach for identifying chromosome aberrations and clarifying taxonomic relationships and seek to apply them to resolve the origin and evolutionary history of V. faba.
Journal ArticleDOI
Comparative study of morphology and heterochromatin distribution in three oilseed species of Brassica L.
Faria Akbar,Kazi Begum +1 more
TL;DR: In this paper , morphological traits and nature of heterochromatins in interphase nuclei and prophase chromosomes of three oilseed species of Brassica L. (B. campestris, B. juncea, and B. napus) have been investigated for morpho-cytotaxonomical evaluation.
References
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Journal ArticleDOI
Selfish DNA: the ultimate parasite
Leslie E. Orgel,Francis Crick +1 more
TL;DR: The DNA of higher organisms usually falls into two classes, one specific and the other comparatively nonspecific, and it seems plausible that most of the latter originated by the spreading of sequences which had little or no effect on the phenotype.
Journal ArticleDOI
Selfish genes, the phenotype paradigm and genome evolution.
W. F. Doolittle,Carmen Sapienza +1 more
TL;DR: Natural selection operating within genomes will inevitably result in the appearance of DNAs with no phenotypic expression whose only ‘function’ is survival within genomes.
Journal ArticleDOI
Evolution of repeated DNA sequences by unequal crossover
TL;DR: Qualitatively, then, unequal crossover provides a reasonable and uncontrived explanation for the prevalence of highly repeated sequences in DNA and for the patterns of periodicity they evince.
Journal ArticleDOI
Evidence for transposition of dispersed repetitive DNA families in yeast
TL;DR: In this paper, Dispersed repetitive DNA sequences from yeast (Saccharomyces cerevisiae) nuclear DNA have been isolated as molecular hybrids in lambdagt and showed marked alterations in the size of the restriction fragments containing these repetitive DNAs.