+ Site Statistics
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on Google+Follow on Google+
Follow on LinkedInFollow on LinkedIn

+ Translate

Trends of chromosome evolution in family commelinaceae

Nucleus (Calcutta) 27(3): 231-241

Trends of chromosome evolution in family commelinaceae

Taxa (24) belonging to 12 spp. under 8 genera, representing members of both the tribe Commelineae and Tradescanticae, were studied. Different populations belonging to the representative species were collected. In view of the profuse vegetative propagation and almost obsolete sexual reproduction in the family, a study of the population-wise differences in these species was called for, both in the finer details of chromosome structure and behavior and the phenotypic differences, if any, among populations growing in different areas of the subcontinent. Three sizes of chromosomes have been observed among the taxa studied, the smallest being in Murdannia, medium sized in Commelina and culminating in the long chromosomes of Callisia, Rhoco, Setcreasea and Zebrina. Commelineae and Tradescanticae are characterized by 2 haploid sets of chromosomes; the former having x = 10, 11, 12, 13 and 15 or multiples of them and the latter mostly x = 6 with occasional polyploidy. There is a remarkable constancy in chromosome number commenlinaceae in spite of minor phenotypic differences and wide distribution in various climatic zones. The constancy of the particular chromosome set might have some adaptive value leading to selective advantage. In Commenlineae, there are minute karyotypic differences as evidenced by their karyotype formula, along with evidences of polyploidy. Both polyploidy and structural alteration have been effective in the evolution of species as well as intraspecific genotype. A study of the karyotypes in Tradescantieae indicates that rearrangement of chromosome segments has played a significant role in the evolution of populations. Such rearrangement may lead to non-homology of segments giving rise to univalents noted in meisois. Structural alterations and possibly hybridity have affected the number of chromosomes with secondary constriction. Tradescantieae has a distinct karyotype, which had undergone considerable alteration and rearrangement during evolution. Cryptic changes in karyotypes have been responsible for the origin of intraspecific races. In both tribes, the various populations studied showed a constancy in chromosome number with a marked change in their chromosome structure. These changes may be minute rearrangements of chromosome parts in certain taxa and addition or dejection of segments in the other. These, along with polyploidy and hybridization, may be responsible for the evolution of new strains. Populations or intraspecific races. The 2 must have diverged quite early during the evolution of the family.

Accession: 006839576

Related references

Kenton, A., 1984: Chromosome evolution in the Gibasis linearis group (Commelinaceae). III. DNA variation, chromosome evolution, and speciation in G. venustula and G. Heterophylla. Chromosoma 0(4): 313-310

Kenton, A., 1984: Chromosome evolution in the gibasis linearis group commelinaceae 3. dna variation chromosome evolution and speciation in gibasis venustula and gibasis heterophylla. Karyotypes, DNA amounts and meiotic behavior were examined in population samples of 2 closely related species. G. venustula and G. heterophylla and their F1 hybrids. All samples were diploid (2n = 12). DNA amount was similar in G. heterophylla, G....

Rao, R.; Raghavan, R.; Kammathy, R., 1972: Biosystematic studies on Indian Commelinaceae--the chromosome pattern and evolutionary trends

Rao R.S.; Raghavan R.S.; Kammathy R.V., 1970: Bio systematic studies on indian commelinaceae the chromosome pattern and evolutionary trends. Bulletin of the Botanical Survey of India 12(1-4): 242-254

Jones, K., 1974: Chromosome evolution by Robertsonian translocation in Gibasis (Commelinaceae). Two cytotypes of G. schiedeana, a self-sterile diploid with 2n = 10 ( x =5) and a self-fertile autotetraploid with 2n = 16 (x = 4), were investigated. Single chromosome sets in the former consisted of two metacentrics + three acrocentrics and in t...

Jones, K., 1974: Chromosome evolution by robertsonian translocation in gibasis schiedeana commelinaceae. Chromosoma (Berlin) 45(4): 353-368

Jones K.; Kenton A.; Hunt D.R., 1981: Contributions to the cyto taxonomy of the commelinaceae chromosome evolution in tradescantia section cymbispatha. The 5 spp. of Tradescantia sect. Cymbispatha [T. gracillima Standley, T. plusiantha Standley, T. poelliae D. R. Hunt, T. standleyi Steyerm. ex Standley et Steyerm, T. commelinoides Schultes fil.] studied, have chromosome numbers of 2n = 12, 14, 16...

Kenton, A., 1981: Chromosome evolution in the gibasis linearis alliance commelinaceae 1. the robertsonian differentiation of gibasis venustula and gibasis speciosa. Two related species of Gibasis, G. venustula (x = 6) and G. speciosa (x = 5), are differentiated by a Robertsonian fusion. Meiotic analysis of the F1 hybrids has revealed further chromosome differentiation of the parent species, involving several...

Gracia-Velazquez, A., 1984: Chromosome study of Zebrina pendula Schnizl. (Commelinaceae). I. Variation in the chromosome number at the tetraploid level, n.f. 28. Agrociencia (58) 59-72

Nash, W.G.; Wienberg, J.; Ferguson-Smith, M.A.; Menninger, J.C.; O'Brien, S.J., 1999: Comparative genomics: tracking chromosome evolution in the family ursidae using reciprocal chromosome painting. The Ursidae family includes eight species, the karyotype of which diverges somewhat, in both chromosome number and morphology, from that of other families in the order Carnivora. The combination of consensus molecular phylogeny and high-resolution...