
	Where results make sense

Topic: Polyploid

Related Topics

Ploidy

Aneuploidy

Evolutionary biology

Gene therapy

Common descent

Douglas Futuyma

Biological cell

Gene

Theory of evolution

Argument from evolution

Taproot

Dandelion

Natural selection

Cindy Dall

Brainiac 5

	Evolution: The Evolution of Polyploidy
		These are 1) the origin of polyploids, 2) the establishment and coexistence of polyploids in diploid populations, and 3) the spread of polyploids into habitats not occupied by their diploid progenitors.
		A problematic and critical step in polyploid evolution is the establishment, and subsequent persistence, of the polyploid (Fowler and Levin, 1984).
		Polyploids are known, in general, to have higher stress tolerances and therefore may occupy separate habitats from their diploid ancestors (Levin, 1983).
	www.geocities.com /we_evolve/Plants/polyploidy.html (3218 words)

	Turfgrass genetic resistance to insects, polyploid Stenotaphrum secundatum St. Augustinegrass and virulent southern ... (Site not responding. Last check: 2007-11-06)
		Turfgrass genetic resistance to insects, polyploid Stenotaphrum secundatum St. Augustinegrass and virulent southern chinch bugs Blissus insularis
		Busey, P. Polyploid Stenotaphrum germplasm: resistance to the polyploid damaging population southern chinch bug.
		This study examined polyploid germplasm for resistance to the PDP southern chinch bug.
	grove.ufl.edu /~turf/refs/ref27.htm (240 words)

	Hurst - Creative Evolution
		Polyploid species, however, differ fundamentally from polyploid varieties, inasmuch as their polyploid sets of chromosomes and genes are those of more than one diploid species while polyploid varieties have the chromosomes and genes of a single diploid species.
		The unequal polyploid species with unbalanced (bivalent and univalent) chromosomes consisting of 7 bivalents and either 7, 14, 21 or 28 univalents have an irregular meiosis followed by a regular but unequal gametogenesis in which the female gametes have twice, three times or four times the number of chromosomes found in the functional male gametes.
		With regard to the unequal polyploid species with unbalanced bivalent and univalent chromosomes: omitting those with more than one septet of bivalents which are natural hybrids and omitting triploids which are not found in a wild state as established species, 55 polyploid septet species are possible, viz.
	www.bulbnrose.com /Roses/Hurst/HURST.HTM (2599 words)

	Polyploidy: From Evolution to Landscape Plant Improvement
		Polyploids also tend to be more self-fertile and apomictic (producing seeds with embryos derived directly from maternal tissue, not sexual hybridization).
		Since polyploids generally arise at a low frequency, greater self fertility and apomixis would help to compensate for their minority-disadvantage (Briggs and Walters, 1977) and would provide further benefits in areas where breeding systems are compromised in stressful environments.
		However, despite the fact that polyploids have been developed for many major crops, these plants are almost always found to be inferior to their diploid progenitors.
	www.ces.ncsu.edu /fletcher/programs/nursery/metria/metria11/ranney/polyploidy.htm (2880 words)

	Polyploidy in plants
		A true allopolyploid or a disomic polyploid is a polyploid species derived from hybridization of parents that had structural dissimilarity between their basic genomes.
		Polyploids often tolerate the loss of one or more chromosome pairs which at times may give rise to modified polyploid series, what Darlington called a ‘polyploid drop’(eg: a modified series found in Hesperis where different species have gametic numbers of n =7,14,13 and 12) (2).
		Polyploids seem to be more tolerant to poor soils, since most of them are slow growers and therefore have more modest nutrient requirements (12).
	www.as.wvu.edu /~kgarbutt/QuantGen/Gen535_2_2004/Polyploidy.html (4736 words)

	The Polyploid Genome Porject (Site not responding. Last check: 2007-11-06)
		The genomic mapping of polyploids, where genome number is higher than two, is complicated by their possible uncertainty about the genotype-phenotype correspondence, different meiotic mechanisms, heterozygous genome structures and increased allelic (action) and nonallelic (interaction) combinations.
		Because many major crop plants are polyploid, e.g., alfalfa, coffee, cotton, banana, potato and wheat, and polyploidization is an important evolutionary force, improved methods for genomic analysis in polyploids are highly needed.
		However, from the viewpoint of meiotic configurations used as a basis for linkage mapping, the nature of polyploids can be better described by bivalent polyploids, in which two chromosomes pair during meiosis to result in disomic or polysomic inheritance, and multivalent polyploids, in which multiple chromosomes pair to result in polysomic inheritance.
	www.biostat.ufl.edu /~cma/polyploid (435 words)

	Centre for Plant Biodiversity Research
		Agamic complexes typically include a series of polyploid sexual, facultatively or obigately agamospermous microspecies, which are largely the result of various hybridizations among sexual diploid and sexual polyploid members of the complex.
		The resultant polyploid agamic complex is comprised of a myriad clones that appear morphologically to represent a giant hybrid swarm, which is usually of multiple hybrid origin from among several sexual relatives.
		He also asserts that the polyploids in these genera do not occur in environments that are more harsh than those occupied by their diploid ancestors, in fact they seem to occupy less extreme environments (Ehrendorfer 1980).
	www.anbg.gov.au /people/bayer1.html (7095 words)

	Polyploidy
		Cells (and their owners) are polyploid if they contain more than two haploid (n) sets of chromosomes; that is, their chromosome number is some multiple of n greater than the 2n content of diploid cells.
		Polyploid plants not only have larger cells but the plants themselves are often larger.
		Polyploid cells are larger than diploid ones; not surprising in view of the increased amount of DNA in their nucleus.
	users.rcn.com /jkimball.ma.ultranet/BiologyPages/P/Polyploidy.html (733 words)

	morula
		In one common example, most animals and plants have tissues in which the cells become polyploid or polytene by means of an S-G cycle, but the mechanism by which mitosis is inhibited in the endo cycle is not understood.
		The endo cycle is the modified cell cycle used throughout the plant and animal kingdoms to produce polyploid or polytene cells.
		In alfalfa the expression of a Cdh1-like gene (homolog of Drosophila Fizzy-related) is increased in nodules that have cells undergoing endo cycles.
	www.sdbonline.org /fly/newgene/morula1.htm (2436 words)

	Evolution: Summary: Polyploid Evolution
		The minority cytotype exclusion principle is a frequency-dependent process that must be overcome in order for rare polyploids to spread in a (randomly mating) parental diploid population.
		Triploids can act as a "bridge" between diploids and tetraploids, and therefore the level of triploid survival and fertility will influence polyploid establishment.
		Burton, T. and Husband, B. (2000) Fitness differences among diploids, tetraploids, and their triploid progeny in Chamerion angustifolium: mechanisms of inviability and implications for polyploid evolution.
	www.geocities.com /we_evolve/Plants/polyploid_summary.html (392 words)

	Soltis, Pamela S. (Site not responding. Last check: 2007-11-06)
		Botanists have long sought to explain the success of polyploid species, with increases in size, colonizing and/or competitive ability, biochemical diversity, and heterozygosity all suggested as possible reasons for the observed success of polyploids in nature.
		All recent evidence on polyploid origins indicates that most polyploid species are the products of recurrent polyploid formation, a process that introduces additional genetic diversity into the gene pool of a polyploid species.
		In combination, the processes that give rise to a polyploid species, those that alter the structure of the polyploid genome, and the inheritance system that operates in a polyploid all contribute to a genetically diverse and dynamic polyploid entity.
	www.ou.edu /cas/botany-micro/bsa-abst/section5/abstracts/18.shtml (305 words)

	Zeng Publication (Site not responding. Last check: 2007-11-06)
		Polyploids are commonly categorized as allopolyploids resulting from the increase of chromosome number through hybridization and subsequent chromosome doubling or autopolyploids due to chromosome doubling of the same genome.
		In this article, we use a maximum-likelihood method to develop a general polyploid model for estimating gene segregation patterns from molecular markers in a full-sib family derived from an arbitrary polyploid combining meiotic behaviors of both bivalent and multivalent pairings.
		Simulation studies show that our polyploid model is well suited to estimate the preferential pairing factor and the frequency of double reduction at meiosis, which should help to characterize gene segregation in the progeny of autopolyploids.
	www.cals.ncsu.edu /genetics/zeng/zz1.html (239 words)

	Polyploid nuclei in human artery wall smooth muscle cells. (Site not responding. Last check: 2007-11-06)
		Although polyploid nuclei have long been known to be present in many adult human tissues, the ploidy of smooth muscle cells in human artery wall has never been determined.
		A significant percentage of nuclei were polyploid; most of these were tetraploid, although higher levels were also found.
		We suggest that the regular existence of a subset of polyploid smooth muscle cells may indicate an important functional role for this phenotype.
	www.arclab.org /medlineupdates/abstract_6572376.html (206 words)

	Multiple Origins and nrDNA Internal Transcribed Spacer Homeologue Evolution in the Glycine tomentella (Leguminosae) ...
		polyploid homeologous loci and loci from extant diploids to
		Shaded boxes on the tree indicate clades that contain polyploid homeologous sequences when the analysis included both diploid and polyploid sequences; exact relationships between diploid and polyploid sequences for each of these clades are illustrated in Fig 2 Fig 3 Fig 4 Fig 5 Fig 6.
		Shaded boxes and large open circles represent sequences from polyploid and diploid accessions, respectively; overlapping circles and boxes represent sequences that were identical in diploid and polyploid accessions.
	www.genetics.org /cgi/content/full/166/2/987 (6732 words)

	Re: What is it about plants that enables polyploid conditions?
		Well, as you are aware many plants are polyploid: although rice is 2n, Wheat is 6n, and corn and most potatos are 4n.
		Some fish are polyploid: the Salmonidae family appears to have arisen by a 2n to 4n genome duplication event (4).
		Lungfish are also polyploid, with some of the largest genomes in the animal kingdom (up to 40X the size of the human genome)(6).
	www.madsci.org /posts/archives/dec99/946001996.Ge.r.html (869 words)

	Plant Materials (Site not responding. Last check: 2007-11-06)
		Arabidopsis has closely related diploid and polyploid species, and analogs of the natural polyploids can be resynthesized from the diploid species.
		Brassica includes diploid and polyploid species that are grown as crop plants through out the world.
		Polyploids can be resynthesized from diploid species in such a way as to create very pure (homozygous) genetic stocks for analysis.
	polyploid.agronomy.wisc.edu /material.html (218 words)

	The Cell Cycle in Polyploid Megakaryocytes Is Associated with Reduced Activity of Cyclin B1-dependent Cdc2 Kinase -- ...
		The platelet precursor, the megakaryocyte, matures to a polyploid cell as a result of DNA replication in the absence of mitosis (endomitosis).
		Of most interest was the observation that the level of large T antigen, as revealed by Western blot analysis, was notably reduced in the cells in suspension (polyploid cells) but not in the adhering cells (mostly diploid cells) cultured at the same nonpermissive temperature (Fig.
		In the case of the megakaryocytic lineage, the endoreduplicated DNA is all concentrated in one nucleus (Metcalf, 1989).
	www.jbc.org /cgi/content/full/271/8/4266 (6636 words)

	Gene Silencing in a Polyploid Homosporous Fern: Paleopolyploidy Revisited (Site not responding. Last check: 2007-11-06)
		Gene Silencing in a Polyploid Homosporous Fern: Paleopolyploidy Revisited
		In polyploid sporophytes of the homosporous fern pelleae rufa, however, progressive diminution of phosphoglucoisomerase activities encoded by one ancestral genome culminates in tetraploid plants exhibiting a completely diploidized electrophoretic phenotype for this enzyme.
		The demonstration that such gene silencing can make a polyploid fern look isozymically like a diploid questions the validity of isozyme evidence for testing the paleopolyploid hypothesis and supports the proposed role of polyploidization followed by genetic diploidizaton in the evolutionary history of homosporous pteridohytes.
	www.biotech-info.net /silencing_fern.html (146 words)

	Functional Genomics of Plant Polyploids (Site not responding. Last check: 2007-11-06)
		More than 70% of flowering plants have had at least one polyploid event in their lineage, either by doubling of a single genome (autopolyploidy) or, more commonly, by combining two or more distinct but related genomes (allopolyploidy).
		Many important crop plants, such as alfalfa, canola, cotton, potato and wheat, are obvious polyploids, and others, such as maize, soybean, and cabbage, retain the vestiges of ancient polyploid events.
		Early and advanced generation polyploids of Brassica will be compared to test for stabilization of changes in the generations after polyploid formation and whether these changes are concerted and mimic natural polyploids.
	polyploid.agronomy.wisc.edu /project.html (469 words)

	American Journal of Botany, 31, 8, October, 1944 (Site not responding. Last check: 2007-11-06)
		An internally or totally polyploid sector was recognized by the occurrence along a branch of wider-than-normal leaves interspersed at certain intervals with normal leaves.
		The isolation and propagation of a polyploid form contained in a sector was accomplished by cutting back the branch to a leaf characterizing this form, and forcing into growth the bud at the axil of that particular leaf.
		Polyploidy seems to bring about principally enlargement of cells in the polyploidized internal tissues of the stem without increasing the cell number in the internal tissues; while cell number in the epidermis is affected both by polyploidy and by cytological constitution of the underlying tissues.
	www.botany.org /ajb/00029122_di001425.html (2088 words)

	Polyploid????????? - Edge Forums (Site not responding. Last check: 2007-11-06)
		I know that the method used to make it is shaky at best with most seeds dying from the colchicine treatment, and the rest possibly not even going on to become polyploid, but i would have thought that some adventurous breeder would be doing extensive work on creating a polyploid strain.
		If you do enduce the polyploid cell condition then you have the next factor to consider which is passing the condition on to future offspring.
		Polyploid (what the original question was about, remember?) is a condition resulting from a whole number multiplication of the number of chromosomes, notated by Xn where X= any # >2, n - the number of chromosomes in a gamete of that species.
	www.overgrow.com /edge/showthread.php?t=47518&onlyuser=&perpage=15&highlight=polypoid?pagenumber=2 (5742 words)

	Gilding the Lily: Developments in Asiatic Hybrid Lilies
		The word "polyploid" is a specific term which indicates that a plant has more than the normal quantity of genetic information.
		The answer to this question is yes, because polyploid plants often possess a number of interesting, and potentially valuable, characteristics.
		From the point of view of a lily grower, however, the most important aspects of polyploid plants includes the bigger flowers, thicker petals and stronger stems which are often found on polyploid plants.
	www.gardenline.usask.ca /misc/tetraplo.html (913 words)

	EUROPA - Research - Quality of Life - Cell factory - Community funded projects (Site not responding. Last check: 2007-11-06)
		The main objective of this research project is to use and further develop molecular tools as screening methods to determine the genetic identity of polyploid and introgressed populations.
		The objective is to use and further develop molecular tools as screening techniques to determine the genetic identity of introgressed populations of polyploid plants.
		Recommendations for appropriate use of techniques will be invaluable in the selection of material for stock establishment, breeding lines and germplasm collections and in the development of management strategies for the utilisation of germplasm at the landscape level.
	europa.eu.int /comm/research/quality-of-life/cell-factory/volume1/projects/qlk3-2000-00227_en.html (591 words)

	Instant Evolution
		Polyploid animals are far less common than polyploid plants.
		In support of these ideas is the observation that polyploid animal species tend to have sex chromosomes that are more similar than those of animals that do not.
		On paper, the repeated origins of polyploid species give these plants a large amount of genetic variability in a short period of time.
	www.wsu.edu /NIS/Universe/instant.html (1118 words)

	SOLTIS, DOUGLAS E.* AND PAMELA S. SOLTIS. (Site not responding. Last check: 2007-11-06)
		Perhaps one of the most significant discoveries is that most polyploid species have originated repeatedly.
		Fine-scale population genetic studies indicate, in fact, that individual populations may be mosaics of genotypes, representing independent polyploid events.
		Despite these advances in our understanding of polyploidy, surprising little is known about the processes responsible for the origin of polyploids, the conditions that favor the establishment and coexistence of polyploid cytotypes in diploid populations, and the impact of polyploidy on plant-animal interactions.
	www.ou.edu /cas/botany-micro/bsa-abst/sympos1/abstracts/5.shtml (264 words)

Try your search on: Qwika (all wikis)