Polyploidization

Fig. 2. Karyotype of 10 S. cerevisiae strains. Intact chromosomes have been separated electrophoreticaUy by size in a TAPE gel. (a), gel mn to separate most chromosomes. Large chromosomes are at the top, smaller at the bottom. Since most strains are polyploid, more than 16 bands may be observed, (b). Chromosomes from the same strains have been separated in a gel mn to enhance resolution of the smaller chromosomes, corresponding to the 4—5...

According to Rowson, polyploids of solanaceous plants, induced by the action of colchicine, show an increased content of alkaloids, but the relative proportions of hyoscine and hyoscyamine remain the same and are characteristic for the species. 

Perityle is a genus consisting of ca. 63 species distributed primarily in western North America and Mexico, with one species in Chile and Peru (Karis and Ryding, 1994). The species of interest is P. emoryi Torr., an annual, polyploid, weedy species that... 

Bayer, R. J. 1990. Investigations into the evolutionary history of the Antennaria rosea complex (Asteraceae Inuleae) polyploid complex. Plant Syst. Evol. 169 97-110. 

Wolf, S. J. and Denford, K. E. 1983. Flavonoid variation in Arnica cordifolia an apomictic polyploid complex. Biochem. Syst. Ecol. 11 111-114. 

The incidence of nuclear anomalies in bone marrow interphase cells significantly increased (p<0.05) in Chinese hamsters gavaged on 2 consecutive days with 2,500 and 5,000 mg/kg/day of Reofos 50 (Ciba-Geigy 1984a), but not in those dosed with 1,250 mg/kg/day. The types of anomalies used in scoring were single "Howell-Jolly" bodies, fragments of nuclei in erythrocytes, micronuclei in erythroblasts, micronuclei in leucopoietic cells, and polyploidal cells. 

PLATELETS. Platelets are nonnucleated discoid or elliptical cells that originate from the fragmentation of giant polyploid megakaryocytes located in the bone marrow. The average diameter of the platelet is 1.5 pm. Each platelet is surrounded by a trilaminar membrane, and its cytoplasm contains a dense body (delta granule), a surface-connected canalicular system,... 

Leevers It is unnecessary most larval (polyploid) cells are going to lyse during metamorphosis. 

Feng H, Zhong W, Punkosdy G et al 1999 CUL-2 is required for the Gl-to-S-phase transition and mitotic chromosome condensation in Caenorhabditis elegans. Nat Cell Biol 1 486-492 Hedgecock EM, White TG 1985 Polyploid tissue in the nematode Caenorhabditiselegans. Dev Biol 107 128-133... 

One property expected of the genetic material is a constancy of amount in every cell of the body under every environmental situation. DNA, not RNA or protein, fulfills this expectation. Its content per nucleus is the same in every cell except the germ cells, which have exactly half that found in the somatic cells. Again, this is expected if progeny obtain half their characteristics from each parent. This constancy is so dependable that the measurement of the DNA concentration in a tissue can be used to calculate die number of nuclei and thus the number of cells. This works well for diploid cells such as those of the kidney, but corrections must be made for polyploid mammalian liver or cancer cells. 

Fig. 8. Root tip cells of A. cepa treated with 100 mg L 1 COL showing the presence of polyploid cells (PC) at magnification of 400x (A) and lOOOx (B).

Musc/skel = musculoskeletal N = haploid cells 4N = polyploid cells NOAEL = no-observed-adverse-effect level NS = not specified Resp = respiratory (W) = water wk = week(s)... 

The wild species form a polyploid series from diploid (2n = 2x=24) to hexaploid (2n = 6x = 72) in which genomes were classified into five groups A, B, C, D and P by Matsubayashi (1991), with a sixth group E recognized in closely related non-tuber-bearing species. Spooner et al. (2004) summarized the putative genome compositions of the polyploid species, but it is clear... 

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