Authors use inappropriate terminology in "lower" paper.

I know that many medically-oriented geneticists don’t understand even the basics of evolution, but do they have to make it so painfully clear?

Schlegel A, Stainier DYR. (2007). Lessons from “lower” organisms: what worms, flies, and zebrafish can teach us about human energy metabolism. PLoS Genet 3(11): e199 doi:10.1371/journal.pgen.0030199

Some tidbits:

Recent studies using the worm Caenorhabditis elegans, the fly Drosophila melanogaster, and the zebrafish Danio rerio indicate that these “lower” metazoans possess unique attributes that should help in identifying, investigating, and even validating new pharmaceutical targets for these diseases.


As will be discussed below, unbiased methods have been used to identify more genes whose mutation in lower metazoans leads to phenotypes that are comparable to human syndromes of altered energy homeostasis like obesity.

Rather, studies on energy homeostasis in C. elegans, Drosophila, and zebrafish are proving that genetically tractable lower organisms can alter our understanding of the relationship of metabolic processes underlying obesity and its related illnesses (atherosclerotic vascular disease and type 2 diabetes mellitus).


11 thoughts on “Authors use inappropriate terminology in "lower" paper.

  1. Strange how the ladder of progress persists. I know I was rather jealous when I found out that squid eyes lack our blind spot.

  2. What terminology do you prefer to refer to the lower animals?

    I’m curious, because I’m often comparing my gene of interest to orthologs and paralogs in other animals. Clearly, duplication since drosophila has resulted in multiple members of this gene family. I know enough not to say “lower”, but how do I generalize to say that from flies to worms to mammals we’ve found the need to create more members of this gene family for more complex tasks? On one axis you have number of family members, and on the other you have, what? Complexity? More and more distance between common ancestors? What word or words other than “lower” would make the authors’ statement true?

  3. Usually when someone writes a blog entry that includes some amount of complaining about another person’s writing style, it includes an explanation and/or correction of the error.

    Otherwise it’s just whining.

  4. To be fair, the title at least puts “lower” in scare-quotes, indicating that the authors are aware that the terminology is wrong, even if the scare-quotes don’t extend to the text itself. What I find more annoying is cases where people use “lower” without any such admission.

  5. Anon, I think whining is unfair. T.R. is just automatically assuming his audience knows exactly what nomenclature would be more appropriate.

    I’m really not sure what is, I’m sure he’ll clarify given some time.

  6. @MarkH & Anon,

    The standard response is that there’s no such thing as a “lower” organism.

    The higher/lower distinction is actually pre-evolutionary, and goes all the way back to Aristotle’s Scala Naturae or “Great Chain of being” where all organisms were ordered according to perfection (& closest to god)

    What evolution tells us is that this chain idea is wrong, we need to take a tree-based view of the world.

    We aren’t “more” evolved than chimps – we’re just as evolved. We’re not “more” evolved than flatworms – we’re just as evolved.

    We have a rather myopic view here, thinking that we as humans are “more evolved” other species (which usually translates to “better than”). This is wrong – yes, we may be better at exploiting the cognitive niche than chimps or flatworms, but they’re better at brachiating or wriggling under rocks than we are.

    The way I like to think of it is like a great evolutionary running race. All organisms started at the same place a few billion years ago, and we’ve all been running (albeit in different directions) since then.

    –Simon

  7. @MarkH:

    I absolutely agree. However I would argue that many readers/subscribers to a blog such as this are here because they are NOT experts in evolutionary biology.

    If I was an expert, why would I need to read this blog? 😉

    <"whining" was mainly to get the discussion going.>

  8. Mark — you don’t need any such term, because the entire idea is fallacious. For example, if you really think that there is a category that includes fishes (vertebrates) and flies (arthropods) and excludes mammals (vertebrates), then I would have serious doubts about how you will be interpreting your comparative genetic analysis.

    What do you mean “duplication since Drosophila”? Drosophila is a modern genus. It is not a common ancestor of any vertebrates.

    As to “we’ve found the need to create more members of this gene family” — you have it exactly backwards, even assuming that copy number is linked with complexity. The mutation happens first, not in response to need.

    As to what the authors could have said, there is no term needed.

    Here is what they said:

    “Rather, studies on energy homeostasis in C. elegans, Drosophila, and zebrafish are proving that genetically tractable lower organisms can alter our understanding of the relationship of metabolic processes underlying obesity and its related illnesses (atherosclerotic vascular disease and type 2 diabetes mellitus).”

    And here is what they could have said:

    “…proving that genetically tractable model organisms can…”

    or

    “…proving that genetically tractable organisms can…”

    Their use of “lower” (even in scare quotes) is gratuitous and incorrect, and I am puzzled as to why the reviewers let it pass.

    As to my whining, no one is forcing you to read it, anon.

  9. “…from flies to worms to mammals…”

    No such transition occurred, and your comparison is among modern species whose lineages have all been evolving for exactly the same length of time since their split from a common ancestor >500 million years ago.

  10. Yes, the use of the adjective “lower” seems unjustified in the paper.

    However, I don’t believe that most people that use the lower/higher characterization really know something about Scala Naturae. The persistent use of some popular, yet incorrect, notions in life-science papers may be usually explained, IMHO, by a combination of ignorance (they really didn’t know the difference), sloppiness (“who cares about philosophy?”, “it’s good enough”) and miscalculation (“it’s exactly what is needed for the target audience!”).

    By the way, what irks me even more is the repetition of old slogans (like the one suggesting that the idea of a Great Chain of Being originates in the work of Aristotle), when translation of the original texts are easily available on the net.

    Iant

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