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- 1 Trout
- 2 There
- 3 Polyploidy in humans (?)
- 4 Abberations in diploidy
- 5 Success of various polyploid species
- 6 A summary figure for all polyploids
- 7 Homolog vs Homeolog
- 8 In-line refs
- 9 Tardigrades
- 10 Diandry and digyny effect on human fetus swapped?
- 11 Discussion elsewhere
- 12 Bacteria and Archaea!
- 13 what is the observable effect?
- 14 How is the work of Gurdon and Yamanaka relevant?
- 15 Etymology
I arrived at this page looking for information on a recent record setting trout catch contested because artificial triploid trout were introduced to the lake in question 9 years ago- the news story was ambiguous in as much as it stated the escaped triploid trout were sterile; it appears that lake trout live 7 years max, the effect of genetic modification is obviously unknown, nevertheless I hoped for some clarifying information on the subject from wikipedia, whereas the article mainly addresses cellular mechanics, leeches, worms, and a rare desert guinea pig. Given our rapidly increasing ability to modify organisms, I think this page would benefit from a discussion of genetically modified animals, sterility, environmental impact of such, etc. — Preceding unsigned comment added by 184.108.40.206 (talk) 04:16, September 17, 2009
There is little more than a dicdef here; I propose moving the Haploidy, Diploidy, Haploidisation, Polyploidy, and Aneuploidy pages to Ploidy. You have to read all those articles to understand ploidy anywho. I'll be happy to do the merge after approvial. Lefty 16:03, 2005 Mar 12 (UTC)
- The rationalistation it should go more like this:
- Ploidy + Haploidy + Haploidisation + Diploidy (regular ploidy)
- Aneuploidy + monosomy + trisomy (abnormal number of chromosomes)
- Polyploidy and its variants (doubling of chromosome numbers) --
I am planning to expnd poliploidy significantly, so a merge would not be helpful at this point.
nixie 22:11, 13 Mar 2005 (UTC)
There are triploid species of wheat? I don't know enough about wheat to definitively reject this, but it sounds absurd. Sporophytes must have a ploidy that is a multiple of two...I can't imagine how a triploid would be fertile.
- Wheat is is hexaploid (6n), which is not the same a triploid (3n). Triploids are normally sterile.--nixie 22:11, 13 Mar 2005 (UTC)
== References == Please put references in the text and in the "references" section. "Further" reading is for documents that were not used but could interest the reader to learn more.
Polyploidy in humans (?)
User:tcopley I've submitted a proposed update to the polyploidy in humans section of the article. Polyploidy in humans is possible although it is rare, in the liver is the biggest example i've been able to find; true polyploidy refers to a complete gnome number shift, aneuploidy is an unbalence in the number of chromosomes. (eg extra X chromosome) I think this distinction needs to be made in refrence to polyploidy in humans.
Endopolyploidy is a type of non-heritable polyploidy that is common across species, in which a subset of specialized cells may duplicate their genomic complement in an otherwise diploid organism. Polyploidy and aneuploidy are both also assocaited with cancerous cells. Hnrtshnrt 21:39, 14 November 2007 (UTC)
User:matt_perez In a recent study, reported by The Whitehead Institute for Biomedical Research, researchers found "that as the developing larval fruit fly brain grows by cell division, it instructs subperineurial glia (SPG) cells that form the blood-brain barrier to enlarge by creating multiple copies of their genomes in a process known as polyploidization. The researchers report their work this month in the journal Genes and Development." Although this study was done on a fruit fly model, the article goes further to say that "cell layers in the human placenta and skin may employ polyploidization to respond to the need to expand while maintaining a sound boundary between the fetus and its surroundings, and the body and the outside world, respectively." It's a big "may" for humans but I think think it is worth mentioning this development on this page.
Abberations in diploidy
The article says: "Where an organism is normally diploid, some spontaneous aberrations may occur which are usually caused by a hampered cell division." What is the significance of diploidy abberations in relation to polyploidy? This seems completely out of place as the second sentence of the article! The sentence is even ambiguous. What does "normally" mean here? -Pgan002 20:02, 20 September 2006 (UTC)
- Hope this helps, hope this is what you are looking for: Normally means in 'wild type', The average ploidy found across all healthy organisms of the species. The idea that an abberant mitotic event can result in a new cell with 2x the number of chromosomes is a big deal to evolutionary scientists. This spontaneous chromosome doubling allows for lots of cool things to happen in nature: plants can't often pollinate other species because their chromosome have no homologues to align with during miosis (forget all the other things that hamper cross pollinating) but a chromosome doubling event provides a solution, double chromosomes by definition have a homologus partner to line up next to. This sort of strange situation may sound ridiculous but without it we wouldn't have wheat! Bread Wheat is the product of two such merge-and-double events. Even humans cna use this info. A researcher, Karpechenko, tried to make a plant with the leaves of cabbage and the roots of a radish, he crossed them, happened to get a doubling event, and produced the world's first man made species : Raphanobrassica. Unfortunatly he got the leaves of radish and the roots of cabbage, hehe.. Hope this is the explanation you're looking for, I do agree that the sentance you're citing is poorly written tho! Adenosine | Talk 08:55, 21 September 2006 (UTC)
Success of various polyploid species
I think this page needs to discuss the success of various species that exhibit polyploidy, such as the American Elm, or the Dandelion. Is there a scientific consensus about whether (and why?) there is an evolutionary benefit to polyploidy? Cazort 13:52, 26 September 2006 (UTC)
There is a growing body of evidence, particularly in plants, that polyploidy has played an important role in both speciation and variation. Explosions in species diversity in the Angiosperms appear to coicide with ancient polyploidization events in ancestors of extant lineages. Nearly all plants are polyploid or have polyploid ancestry. Numerous studies in recent years with resynthesized plant polyploids have found that processes of both hybridization and polyploidization are frequently associated with genetic changes, epigenetic changes, changes in gene expression, and phenotypic variation. It is thought that such changes may contribute to the processes of speciation or niche exploitation.Hnrtshnrt 21:50, 14 November 2007 (UTC)
A summary figure for all polyploids
Homolog vs Homeolog
In polyploid species we recognise homeologous chromosomes and homologous chromosomes and their corresponding genes.
If the species is tetraploid and derived from one parent with an A genome and another parent with a B genenome then the tetraploid can be represented AABB. If the parents had 2n=6 then there will be a chromosome 1, 2 and 3 from both the A and the B genomes and the tetraploid will have 2 chromosome ones from the A geneome and two chromosome ones from the B genome. The two chromosome ones from the A geneome are homologous chromosomes and have homologous genes. The two chromosome ones from the B geneome are also homologous chromosomes and have homologous genes. Chromosome 1 from the A genome and chromosome one from the B genome are known as homeologous chromosomes and have homeologous genes. See this article that talks about this stuff. Ttguy 11:26, 24 May 2007 (UTC)
- Homoeologous: is it possible to have a definition or explanation of this term which could be read by users who don't have a PhD in plant cytogenetics? Macdonald-ross (talk) 08:28, 4 June 2008 (UTC)
These are a) inadequate, with whole sections lacking refs, and b) mostly incomplete, lacking title and location. Polyploidy is important enough (certainly to botany) to deserve better. Macdonald-ross (talk) 07:13, 3 January 2008 (UTC)
triploid (three sets; 3x), for example the phylum Tardigrada
The article on tardigrada makes no mention of triploidy. In addition, I can't imagine how triploidy would work. How would meiosis work in a triploid organism? Does one sex produce haploid gametes and the other produces diploid gametes? How would such a system have evolved? It seems like triploid could not be stable, as it would tend to become either diploid (two haploid gametes) or tetraploid (two diploid gametes) Nik42 (talk) 00:23, 27 October 2008 (UTC)
Diandry and digyny effect on human fetus swapped?
I read the description of how diandry and digyny affects the fetus as swapped compared to what I can read here http://www.healthline.com/galecontent/triploidy.
- Yes, that source certainly contradicts what is on the page. That section could do with considerable simplification, and added citations, possibly a quite drastic change of emphasis. I'm not really familiar with this material. Hopefully an expert can see how to fix it. Nadiatalent (talk) 00:39, 24 September 2010 (UTC)
Bacteria and Archaea!
This article is written from a eukaryote prospective, and yet polyploidy is more common in bacteria and archaea than in eukaryotes. After recently learning that the halophilic archeon Haloferax volcanii is a variable polyploid, with between 15 and 30 genome copies per cell, I came her to review some of the basic of polyploidy. (I was actually interested in thinking about how polyploidy affects gene knockout experiments.) However, I was shocked to see that this article doesn't even mention polyploidy in non-eukaryotes. For example, there is no mention of Epulopiscium fishelsoni, which is an exceptionally large bacterium and also exceptionally polyploid with 100-200 thousand copies of it's genome within the typical cell (where each cell is 106 times larger in volume than a typical E. coli).
Compared with plants and animals, bacteria and archaea are more often polyploid and exhibit a much larger range of variation in polyploidy. A large fraction of this article ought to be devoted to that. Dragons flight (talk) 17:43, 5 May 2011 (UTC)
what is the observable effect?
Someone who knows needs to add info about the observable effect of polyploids. To me, all I see is DNA and biochemistry. Does it have any visible effect at all (if the animal lives)? Does it give you super-powers? Does it make the baby have two heads, or what?
- Effects have been seen, but there seems to be little in the way of generally applicable observations. The phenomenon is quite well known in yeast and in plants, where new polyploids can look very much the same as their diploid ancestors. Over a few generations there can be major changes, however. This paper discusses those evolutionary changes. Sminthopsis84 (talk) 00:24, 24 September 2012 (UTC)
How is the work of Gurdon and Yamanaka relevant?
I can't see how this is relevant:
"John Gurdon (1958) transplanted intact nuclei from somatic cells to produce diploid eggs in the frog, Xenopus (an extension of the work of Briggs and King in 1952) that were able to develop to the tadpole stage. The British Scientist, J. B. S. Haldane hailed the work for its potential medical applications and, in describing the results, became one of the first to use the word “clone” in reference to animals. Later work by Shinya Yamanaka showed how mature cells can be reprogrammed to become pluripotent, extending the possibilities to non-stem cells. Gurdon and Yamanaka were jointly awarded the Nobel Prize in 2012 for this work."
Could the link to polyploidy be explicitly stated, or else this part deleted?
Having a degree in genetics, I can't see how Gurdon's work had anything to do with polyploidy. He simply inserted a somatic nucleus (diploid) into an oocyte.
- Agree, that doesn't belong here. It could be relevant to a discussion of genomic imprinting, which relates to polyploidy, but it is just a stray fragment. Sminthopsis84 (talk) 15:24, 14 January 2014 (UTC)