Is it right to speak of animal DNA and plant DNA?

Am I right in believing that there is fundamentally no difference between DNA in a plant and DNA in an animal? That the mechanism is the same.

Hi Noel:

Genetically speaking plants can encode up to 125 different proteins whereas humans can only encode about 25. Molecular biologists generally regard the non encoding DNA as junk DNA. As a general statement plants are far more complex than animals. I guess that shows you how screwed up the modern thinking on this subject can be.

Fascinating!

Don’t HBs self-reproduce proteins more in the range 50,000 proteins?

aguy2

Could you tell me the source of this information? The number of different proteins needed by a living cell far exceeds the numbers you mention (which sound absurd to me).

Hi to everyone:

Apologies to all. I think I have lost my mind. I have found what I thought was my reference material (the November 2003 Scientific American article entitled “The unseen Genome: Gems among the junk”). However it specifically states that there are “…27,000 genes or so that code for protein …[but it could] range from 20,000 to 40,000”. I do not know where I came up with the numbers 125 and 25, unless they are scaled by a factor of 1000. But I simply do not know.

Now that I have screwed up everyone, I would like to ask a favor. I would like to ask for a critical review of my essay on evolutionary mechanisms. If I have made errors such as this I would like to know.

heh… lucky me, i scrolled down just in time, as i was reaching on the floor to get my jaw back.

It happens - it’s OK. Is your essay somewhere on the web?

Hi To Wander

Thanks for your kind words - I really do feel embarrassed.

My essay is about the 33rd one down under Essays and Theses on this site and I really would particularly like your critical comments.

Thanks

I looked at your essay in the “Essays and Theses” forum and found it very interesting with no big errors that I could discern. Don’t feel too bad about your ‘little’ error. Last month I started a thread on another debate forum concerning what possible ‘constraints’ were there that set ‘C’ at 186,000 mph! I was only off by a factor of 3,600!

I have some of the same questions about the long periods of relative biological stasis. I have made some rather ‘fuzzy’ conjectures concerning the internal assimilation of ‘microtubule’ structures as being the primary factor in the onset of eucaryote evolution.

This is interesting but it is not really addressing Noel’s question about differences in plant and animal DNA.

aguy2

Hi to aguy2:

Thanks for your post. I think that you and I have some similar interests, and I hope we can connect on future topics. As you say, this is noel’s post.

Err, still waiting for some replies!

Noel, I’d have to dive into my library (sorry, no time…) but just from memory I can say this: DNA is a substance, stuff you can isolate, purify and put in a test tube. So from a biochemical point of view, DNA is just that: DNA. In that sense, there is no difference between the DNA of plants and animals. Where it gets interesting, of course, is how a plant becomes a plant and an animal an animal, given that both are outfitted with the same genetic material. This, of course, is where the genetic code comes in. At this point, two major elements of this code seem to be relevant. First, the ratio of “coding” vs. “non-coding” DNA (i.e. the number and length of exons vs. the number and length of introns). Second, when looking only at the coding DNA, the number of genes and the precise genetic code contained in them are important. Plants and animals share a lot of cellular processes (glycolysis, citric acid cycle, oxidative phosphorylation, transcription and translatiuon, membrane transport, etc) so obviously the genes needed for these processes are present in both. Processes that are unique for either plants OR animals are naturally coded for by genes not present in the other. Examples are the formation of cell walls or chloroplasts and photsynthesis in plants and the formation of bones and brains in animals.

It should be noted that non-coding DNA is probably far from irrelevant. For a really good piece on that, see this article - it offers a lot of information on the subject if you ignore the creation vs. evolution undertone.