What are the potential benefits of additional chromosome pairs?

I know that extra chromosomes are usually a bad thing, but at the same time I've heard stories (science fiction, of course) where additional chromosome pairs brought about beneficial mutations.

Tell me, in reality, is there any potential benefits to additional chromosome pairs?

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  • Anonymous
    6 years ago
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    "What are the potential benefits of additional chromosome pairs?"

    Tolerance (if not immunity) to ionizing radiation, as detailed below. But Down's syndrome is such a duplication, and is not really a benefit to that organism. There are also supermales, two Y-chromosomes, and not beneficial to the organisms around them (in general).

    "I know that extra chromosomes are usually a bad thing, but at the same time I've heard stories (science fiction, of course) where additional chromosome pairs brought about beneficial mutations."

    There is one organism I know of that is essentially immortal. Its cells have 4 copies of its DNA, and damaged DNA can be repaired against a plurality of the other DNA.

    If course it has to breed by pathenogenisis, which takes all the fun out of sex.

    "Tell me, in reality, is there any potential benefits to additional chromosome pairs?"

    Hardiness to irradiation. There are also organisms with RNA-only (essentially transparent to ionizing radiation), a bacterium with ring-shaped DNA (can only be repaired one way), and our own sex cells are protected by a fully-functional telomerase repair system... just not our somatic cells.

    The downside is, beneficial mutation, as in changes for improved survivability from changes in the environment, are not possible (except for the RNA only system, but they are barely single cells as it is).

  • 6 years ago

    Not likely to be helpful in humans or most other animals.

    In plants, however, polyploidy (more than two sets of chromosomes) happens often and can provide a larger flower, larger fruit or some other characteristic that people might find beneficial.

    See: http://en.wikipedia.org/wiki/Ploidy#Polyploidy

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