The Littlest Genome—Organism Or Organelle?

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Japanese and American scientists report that they have discovered the smallest genome so far in an organism. The organism is the bacterium Carsonella rudii, which lives as an endosymbiont inside a small insect. While humans take around 23,000 genes to make it through the world, the bacterium can keep body (cell) and soul together with only 182 genes. However, it cannot live outside the insect. Scientists speculate that Carsonella rudii may be on its way to becoming an organ rather than organism. Scientists think that this happened to the organism that evolved hundreds of millions years ago into the mitochondria that now serve as thousands of cellular powerplants in each animal cell including humans. Apparently most mitochondrial genes eventually migrated to the nuclei of cells leaving in human mitochondria a genome consisting of 37 genes in the mitochondria themselves.

Researchers like human genome sequencer Craig Venter are trying to figure out the minimum number of genes it takes for an organism to live in the outside world. Even then such a minimized bacterium would require a specialized and protected environment in which to live. Naturally, some bioethicists are concerned about the minimum genome project.

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  1. Minor factual correction – mitochondria do not live in cell nuclei.

  2. It took me a while, Ron, but I finally got the libertarian tie-in. Creation of minimal genome critters could allow the development of non-carcinogenic nicotine, thus allowing us to blow smoke in the faces of those gah-damn prissy-ass liberals! Sign me up!

  3. andyd-

    mitochondria don’t live in cell nuclei, but some of the genes necessary for a mitochondrion to function are indeed found in cell nuclei.

  4. You’re probably joking about not being able to spot the libertarian angle (sarcasm is notoriously difficult to detect on the Internet). Just in case you aren’t, the tie-ins with libertarianism are 1) that scientific exploration should be free from arbitrary limits placed on it by the government at the behest of scientifically illiterate and unethical scare-mongers and 2) that scientific advancement empowers individuals by allowing them to live fuller, richer, more independent lives.

  5. I’d see something like this as a positive development for those afraid of genetic research. If “industrial organisms” can be designed to be too fragile to survive outside the artificial environment they were designed for, then the risk of them escaping into the wider world and proliferating is greatly reduced.

  6. ok now I have to hate the bioethisists again…aparently using reductionist technique in reserching biology and genetics is ethically unsound, regardless of the knowledge gained.

  7. you mean “organelle”, not “organ”

  8. Not that it matters a whole lot, but mitochondria aren’t just found in animal cells, though all animals have them. They’re found in all organisms that aren’t bacteria or archaea, not just animals. Although the post doesn’t say that they’re only found in animal cells, it could easily be read that way. Not that I think that anyone is getting all their science education from Reason, but it’s important to be accurate. 🙂

  9. Not that I think that anyone is getting all their science education from Reason

    And thank God for that!

  10. “Scientists think that this happened to the organism that evolved hundreds of millions years ago into the mitochondria that now serve as thousands of cellular powerplants in each animal cell including humans. Apparently most mitochondrial genes eventually migrated to the nuclei of cells leaving in human mitochondria a genome consisting of 37 genes in the mitochondria themselves.”

    Evolutionist nonsense. Mitochondria are our Jesus Power Nuggets.

  11. The distinction between “inside” and “outside” is really sort of arbitrary. There may be reasons that living inside a cell or an organism makes it easier on a tiny DNA-based creature than not, but either way we’re still just talking about different environments from the perspective the organism.

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