24 August 2009

Word for the day: gynandromorph

What interested me today was the bottom photo of the ?chrysanthemum. Presuming it hasn't been artificially fiddled with, it apparently represents some type of accidental hybrid, or a defect of some coloration gene occurring during development. The photo was at Pixdaus without a link, and I haven't found the photo elsewhere using the TinEye reverse image search.

The mum photo reminded me of the "gynandromorph" phenomenon (half female/half male). It's well known (though still rare) in butterflies, especially where the male and females have different coloration patterns, as in the tiger swallowtail at the top. The phenomenon is also evident in the Chesapeake Bay crab in the next photo and the cardinal below that.

Addendum: Dr. Mieke found the link for the chrysanthemum, which is, indeed, a genetic mutation. In her comment is a link for how you can do this artificially, for fun.

Addendum #2: See the comments by anonymous re the relationship (or not) of gynandromorphs to hermaphrodites and chimeras.


  1. In people, it's known as intersexual. Josephine Joseph being a good example. http://en.wikipedia.org/wiki/Josephine_Joseph

  2. How does this relate to hermaphroditism? Are these creatures Chimeras? Do they posses both sex organs or simply secondary sex characteristics?

  3. The link for the two-colour chrysanthemum is here:
    Having said that, when I was a child, my brother and I used to dye flowers bi-colour by splitting the stem and putting each half in a separate glass with a different dye solution. See http://pbskids.org/zoom/activities/sci/coloringflowers.html ... Fun for the adults, let alone the kids :-)

  4. I actually had a tulip grow this year in my garden which had a strange mutation which may or may not be related to this


  5. oops, i didn't mean to publish that anonymously.

    This link goes to the strange mutant tulip where a green leaf ended up being 50% petal.

  6. @linty - very interesting, since I think a petal is basically a modified leaf...

  7. Zac F- As the article itself points out, Josephine Joseph was probably a fake. I'm no expert, but I don't think half-and-half humans are really possible. Bilaterally-divided arthropods are possible because the first cell divisions in many invertebrates are determinate (zygote splits and one cell will become the left side, the other the right), while this is not the case with humans. Here: http://tinyurl.com/lyulke

    However, I honestly don't know what the deal is with gynandromorphic birds. It just doesn't make sense. If anybody knows, please post.

    Nolandda- hermaphroditic organisms are just organisms that have both male and female sex organs, or that have an exclusive sex but can change it. It's quite common among invertebrates, and is even found in some fish. In humans, the latter is not (really) possible. However, human "hermaphrodites" (or intersexuals) which have both male and female gonads ARE possible. It is also possible for humans to start out appearing to be female, but during puberty "become" male. The reasons for all of this are somewhat complicated, so I'll just give you a link: http://tinyurl.com/l5xpny

    Gynandromorphs are NOT chimeras, and they do posses both sex organs (see first link in reply to Zac for an explanation of gynandromorphs). Of course, the sex organs are oftentimes deformed.

    Naturally-occurring chimeras happen when two non-identical twins are beginning to grow, but for some reason the two (genetically-distinct) individuals fuse and become a single individual. I will speculate here and GUESS that it's possible to have a chimeric gynandromorph, but I don't know that for sure. In humans, chimeras usually take the form of an individual that has patches of genetically-distinct tissues. In fact, I watched a documentary where a woman and her children were genetically tested (forgot why), and the tests indicated that the children were not hers. After a whole ordeal they finally figured out that she was a chimera, and her ovaries were genetically distinct form the rest of her body. It turns out she had her non-existent twin's children. Pretty bizarre.

  8. Oooohhh! I just did some research and found this article: http://tinyurl.com/kn4vbz

    I thought that the reason humans couldn't be gynandromorphs was because of of the indeterminate nature of early embryonic cells, but I don't think that's the case anymore (didn't really make sense in the first place anyway). The key seems to be how the sexual characteristics of the animal are determined. In birds, expression of certain traits (such as plumage, brain pathways, and other stuff) are controlled locally by the sex chromosomes located in the tissue at question. This may also be true of some mammalian traits (examples provided at the end of that article), but mammal sexual characteristics are generally controlled by just a few gonadal secretions (see the discover magazine article: http://tinyurl.com/ks78sg ... why didn't anyone tell me I had screwed up the link?). Because it is impossible to have a mammal like a human have certain hormones on only half of their body, it is also impossible to have it only express the sexual characteristics dependent on said hormones divided like that.

    Hopefully that made sense...


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