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 count?

When published chromosome counts for some polyploidy orchid and rhododendron species were updated such counts showed a multiplication of the original more diploid like count rather than a incremental refinement to a slightly more accurate count already in the polyploidy range.

See Ploidy Orchids

In rhododendron multiple counts of 26 chromosomes for R. austrinum, atlanticum, and luteum have been updated indicating a number of chromosomes for these three species is closer to 52 chromosomes.

Is there something about the way a polyploidy flowering plant species undergoes meiosis or mitosis that causes such miscounting to be the chromosome count for closely related diploids?

  • 1
    $\begingroup$ Your questions do not make sense. Please provide specific examples, i.e. In species x, which chromosomes in that species, etc. The answers will be different based on the organism. Also please use quantifiable terms as a lot and a little are completely subjective. Getting an additional copy of even a part of a chromosome in a human can be lethal during development, others can survive, but lead to dosage dependent conditions. In plants, they can likely sustain polyploidy, but there are probably examples that would be lethal as well. $\endgroup$ – AMR Sep 3 '15 at 15:43
  • 1
    $\begingroup$ Also you could provide links to the studies that you are referring to that generated your questions in the first place. If these are unpublished findings then providing the relevant data for others to evaluate the questions would be productive. $\endgroup$ – AMR Sep 3 '15 at 15:48
  • $\begingroup$ @AMR The question now is specific to flowering plants such as orchids and rhododendron. $\endgroup$ – John Perkins Sep 3 '15 at 17:56
  • $\begingroup$ The question now makes sense, unfortunately I now very little about plant genetics, other than green wrinkled peas and purple or white flowers, etc... Hope someone with knowledge on the subject gets back to you.... My intuition would say however, in your example of 26 to 52, than the plant is completing S phase of mitosis and then stopping, or the cells are multinucleated, sort of like human muscle cells, but again, that is strictly speculation and not based on a knowledge of the subject of the question. $\endgroup$ – AMR Sep 4 '15 at 1:24

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.