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Questions tagged [polyploidy]

Cells and organisms containing more than two paired (homologous) sets of chromosomes.

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How do we know for sure that Morus nigra (black mulberry) is tetratetracontaploidic (has 44 copies of each of its seven chromosomes)?

This answer to Is there any particular reason to choose strawberries for DNA extraction? explains that strawberries are octoploid. Wikipedia's Polyploidy and Morus nigra; Description both point out ...
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Why is the expected time to coalesce the same as the ploidy times inbreeding effective population size?

The expected time to coalesce, in generations, is the same as the ploidy (e.g., 2 for humans) times Nef, the inbreeding effective population size, under coalescent theory. Why? Both ploidy * Nef and ...
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Can hybrids from closely related species with similar chromosomes reproduce?

Let's say the plant Triticum monococcum which has 2 sets of 7 chromosomes when diploid and 1 set of 7 chromosomes when haploid has the genome AA. When interbred with a different species that has the ...
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Why are odd numbers of chromosomes (triploidy, pentaploidy) less common than even ones (tetraploidy, hexaploidy)?

Perhaps there is an obvious reason, and I know that most organisms that are either exclusively sexual or at least capable of sexual reproduction are diploid, but.... Is there a specific reason ...
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Are highly-polyploid organisms more resistant to ionising-radiation-induced DNA damage?

Homologous recombination, although most famous for its use to mix together maternal and paternal alleles during meiosis, is most commonly used as a DNA-repair mechanism, allowing cells to repair ...
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Is there a practical upper limit to ploidy?

In my AP Biology class, we were discussing polyploidy, specifically, its deleterious nature in mammals and its prevalence in plants. We also learned that commercial crops, especially fruit, are often ...
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Pentaploid genotype frequencies

I know that if I am dealing with a diploid case, and I have 3 alleles, then I can have 6 possible genotypes. I am doing this by adding up all the numbers from 1 to 3. $$1+2+3 = 6$$ But if I want to ...
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an umbrella term for homeolog and ohnolog?

Is there a word that refer to homologous chromosomes within a polyploid species? If I have AABB species, what is A to B? The words "homeolog" and "ohnolog" are reserved for the cases if the ...
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How much DNA does a species lose after post-polyploidization genome downsizing?

After whole genome duplication, diploidization takes place, right? A lot of changings in gene organization and expression involving genetic and epigenetic mechanisms (translocations, transpositions, ...
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How does allele dominance work in polyploid organisms?

You know how there are tables to demonstrate allele dominance in diploids, such as the table found in this question? Well, I was wondering how this works with tetraploids, hexaploids, octoploids, etc....
Brōtsyorfuzthrāx's user avatar
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Single copy housekeeping genes

I am working on a tool for SNP calling in polyploid plants. To test my method, I need a list of housekeeping genes common in almost all plants. For my case, these genes must be single copy (ie each HK ...
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Are polyploidal organisms parasatized by selfish genes? And if not, why not?

Certain prokaryotes are polyploids. For example, Thermus thermophilus has about five copies of its genome (http://jb.asm.org/content/192/20/5499.full). One extreme polyploid, Epulopiscium fishelsoni, ...
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What is the 'fallacy' in simple segregation rules in reference to polyploidy?

I was reading a paper Why polyploidy is rarer in animals than in plants’: myths and mechanisms, Mable 2004 where I found this sentence. Stebbins (1950) suggested that autopolyploids were probably ...
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Why is polyploidy much more common in plants than in animals? [duplicate]

There are very few animals with polyploidy like salamanders. Why is it that polyploidy is so uncommon in animals? On the other hand there are numerous examples of polyploid plants. If ut something to ...
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Is it possible for an organism that is polypoloid with an odd number of sets of chromosomes (e.g. 5 sets) to be fertile?

Is this possible, since there is five sets, there would be an unequal separation of homologous chromosomes during anaphase I of meiosis?
Jimmy Nelson's user avatar
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Why is down syndrome more common than other trisomies? [duplicate]

Why is Down syndrome more common than say trisomy 18? Is chromosome 21 easier to replicate? Or is it because those babies are more viable?
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Focusing on flowering plants, are there reasonable explanations why pentaploids would be more fertile than triploids?

For the genus Rhododendron, triploids are sometimes fertile but pentaploids appear to be often fertile. Once Rhododendron seedlings gets above the triploid level, aneuploids not near euploid appear to ...
John Perkins's user avatar
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Why are published chromosome counts for polyploids often incorrect by an integer multiplication factor of the original diploid like count?

Why are published chromosome counts (done using techniques such as root smashes) for polyploidy flowering plants often incorrect by a multiplication factor of 2 or 3 from the original diploid like ...
John Perkins's user avatar
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Differing Flow Cytometry Genome Sizes and Sexual Mating Implies Differing Chromosome Counts

Do the fundamental principles of genetics strongly suggest the following is a derived conjecture? If 2 flowering plant species A and B have widely differing genome size (at a minimum a 50% difference)...
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Can flow cytometric analysis differentiate between a parent contributing longer chromosomes versus multiple smaller chromosomes?

For flowering plants, can flow cytometry of seed from muti-generational interaction of two species and their offspring help us decide if wide differences in genome size for the two species and their ...
John Perkins's user avatar
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Does polyploidy always isolate the polyploids from the diploid source population?

I am receiving conflicting information while researching polyploid speciation. On the one hand, some sources state that a polyploid can only reproduce sexually with polyploids having the same number ...
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Why does polyploidy give an evolutionary advantage?

I would like to know what advantages polyploidy holds. I have come across a few examples during my research of polyploidy, for example human adults' hearts contain 27% diploid, 71% tetraploid and 2% ...
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What is doubling of genetic material invented in flowering plants?

David Attenborough in his Kingdom of Plants 3D said, that flowering plants made two inventions: (1) doubling of genetic material and (2) symbiosis with animals. What was meant by "doubling of genetic ...
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Can diploidy evolve in absence of sexual reproduction?

Theoretical question Can diploidy (or polyploidy) evolve from a haploid lineage in the absence of sexual reproduction ? For what theoretical reason? How can such evolution take place? Empirical ...
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Speciation by polyploidy

Speciation can occur by polyploidy. My understanding of the process is as follows: 'polyploidy is when the number of chromosomes in an organism's cell doubles. This means that the organism has more ...
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Are there any mammals in which polyspermy produces viable zygotes?

Are there any mammals in which polyspermy produces viable zygotes? In the wikipedia page it is mentioned that there is a delicate equilibrium between female defenses against many sperms, which ...
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Why was polyploidy not lethal in certain octodontid rodents?

As discussed in Why is polyploidy lethal for some organisms while for others is not?, polyploidy is normally lethal in mammals. However, two species of Octodontidae (South American rodents), are ...
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Sequencing the genomes of polyploid organisms

I've done some transcriptomics work in the past with a polyploid organism, and this presented some unique challenges in the data processing and analysis. Since then, I have been brainstorming about ...
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Why is polyploidy lethal for some organisms while for others is not?

Polyploidy is the multiplication of number of chromosomal sets from 2n to 3n (triploidy), 4n (tetraploidy) and so on. It is quite common in plants, for example many crops like wheat or Brassica forms. ...
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