For the life of me, I can’t figure out what this sentence is supposed to imply. “Function” how? To do what? Nothing exists in a vaccuum; therefore anything that exists, functions - and unless I’m wrong about the existence of God, DNA wasn’t invented to serve some specific purpose. I don’t think it’s just sloppy language though (though it is Wikipedia) - I think, on the other hand, that people in general have a very hard time abandoning a view of their own place in the world as an inherently privileged one - that the world I can know, is the world.
We can, at least loosely, talk of biological function. A heart pumps blood.
DNA has functions, too. Very loosely, it preserves some information used in physiological activity.
In almost all cases, the specific sequence of a section of DNA is important to its function. When this sequence is interrupted, the function can fail. Thus a section of DNA that tends to be variable between organisms is probably one that does not contribute to physiological activity.
I confess I don’t understand the place of teleological language in scientific description. Functions can “fail” only in the sense that what we desire does not occur. Hearts don’t have a purpose - neither does DNA. My heart may continue to pump even in some hypothetical future wherein I don’t want it to pump anymore. I’ll reassert - anything that exists, functions. How then could junk DNA not contribute to physiological activity? If it doesn’t, it doesn’t exist.
Don’t over-think it. You have an appendix and a spleen which no longer serves any useful physiological “function”. All the statement says is that some DNA strands are broken and they reproduce up to the broken place and never become fully functional. Other strands may replicate, but are canceled by other sequences more fully evolved. You know that Wii paddle you have that lost one of its functions and is now just a paperweight? Or maybe the broken windshield washer pump that’s still on your car but is just hanging there waiting to be junked? It’s all the same thing. In the DNA scenario, function means observable characteristics in the organism caused by a DNA strand. If there are no observable traits related to a strand, it can be said to be not “functional”.
OK. I thought my response addressed the philosophical point that what is functional is by a conditional and provisional definition that has nothing to do with a disinterested universe of energy and bits and pieces. Something is functional or disfunctional because I say so. There is no external absolute condition that demands any particular perspective.
OK. I thought my response addressed the philosophical point that what is functional is by a conditional and provisional definition that has nothing to do with a disinterested universe of energy and bits and pieces. Something is functional or disfunctional because I say so. There is no external absolute condition that demands any particular perspective.
Actually, hmm, a bit theoretic, and not very philosophical (sorry) but junk DNA is useful. In the way that having spare lego in a pile is useful, though not really doing much. Junk DNA mutates just like any other stretch of coding DNA. Sometimes it mutates (it is supposed) into something functional. If whatever it codes for or switches on/off or whatever, is new, cool and funky, it gets propagated through the species.
The reason why eukaryote genomes conserve junk DNA (unlike super-streamlined bacterial genomes) is exactly like the lego situation - so the genome has spare bits to build new shit with. If you ain’t got no spare bits, than you are stuck with what you got already made. And since we don’t swap plasmids, that’s bad news for us multicellular organisms.
anon, there really is no ‘junk’ DNA. There are repetitive DNA sequences that are kind of held in reserve until they’re needed.
I don’t know how this applies to your OP because I’m not exactly sure what it is you talking about in your OP. DNA is the chemical that carries the genetic information of the cell. Its coding is that information. What does this have to do with
What does this have to do with DNA–‘junk,’ repetitive, held in reserve, or otherwise? Please explain.
No, it’s a relevant post. What you’ve pointed out is that if something exists, it functions. On the other hand, it doesn’t function “for me” - it just functions. The “me” doesn’t exist prior to the functioning - it exists as a description of and/or result of the functioning.
I’d point out though that “not really doing much” and “mutates…into something functional” are comments that seem to take the world as currently understood by science as a privileged point of view, which I think is subtly unscientific. It’s like saying that a retired person isn’t really doing much, or that a hermit might mutate into something functional. Yet we have no idea to what extent the world may depend on retired people, or hermits. We don’t even know how these people spend their days.
I read your link concerning biology and purpose. I dunno, for me it’s isolation and context. We can say that “the function of the heart is to pump blood” etc. But really, if you remove the heart from the body, then any function is lost. It’s just a thing that palpitates automatically. It is only given function within the confines and context of a (living) body. But then you can scale up and say “the body as a whole functions to x,y and z.” But really, the buck stops with the sentient awareness within the body, and then function becomes recursive enough to stand alone. ie. The function of the mind is to further the function of the mind. I think somewhere you’ve gotta stick appraisal and intent into the equation.
