we evolved from fruit flies and pumpkins
Hey, I just heard that the DNA overlap between humans and pumpkins is 75%. While checking into this, I read that we share 93% with fruit flies. Maybe these numbers are off, but I'm going to have some fun with them-- along with periodic references to chimp DNA and our supposed evolution from them.
So, drawing some amusing but probably inaccurate inferences from a LiveScience article on monkey vs. human DNA...
The new analysis of the rhesus monkey genome, conducted by an international consortium of more than 170 scientists, also reveals that humans and the macaques share about 93 percent of their DNA. By comparison, humans and chimpanzees share about 98 to 99 percent of their DNA.
The fact that rhesus monkeys are further away from humans in evolution will help illuminate what makes humans different from other apes in ways that chimps, which are so closely related to us, could not, Gibbs said. (Rhesus monkey ancestors diverged from those of humans roughly 25 million years ago, while chimpanzees diverged from our lineage 6 million years ago.)
-We diverged from our fruitfly ancestors about 25 million years ago-- and from our pumpkin ancestors about 60 million years ago.
-Rhesus monkeys diverged from fruitflies on a lazy weekend about 25 million years ago.
-The fact that we are further away from fruitflies than chimps explains why we are more like the latter. The fact that we are further away from pumpkins than fruitflies explains why we are more like the fruitflies than the fruit (or is it a vegetable?).
posted by Eric Schansberg @ 5:13 PM
17 Comments
17 Comments:
I'll get back to you soon: I've got a million monkeys on typewriters in the back room and I'm just waiting on them to hit upon the perfect reply to send you. Hope you can stick around for a few million years or so…
Eric your mockery of evolution is about as ludicrous as your chances of getting elected to congress. Stick to waht you know, economics but you are way out of your league trying to disprove man's evolutionary past.
Ahhh...relax. I indicated in the post that the comments shouldn't be taken all that seriously.
Besides, evolution is true and Evolution cannot be disproven-- so that would be a "fruit"-less exercise.
Eric, you have the right idea; you can infer how long ago common ancestors between two species lived by comparing their genomes (and considering known rates of mutation). But you're mistaken about how similar the fly genome is to the human genome; they are much less similar than 93%. (I could elaborate if you wish.) Anyway, it turns out that the last common ancestor between flies and humans lived about 600 million years ago.
Let's see if we can talk the guys running the Large Hadron Collider into putting a fruit fly in there and let it spin around 600 million times at the speed of light. Maybe a human will pop out... or at least Jeff Goldblum.
sure, elaborate as you see fit...at the least, if you know the real numbers (on fruit flies and pumpkins), let us know!
I'll have to explain a little biology that you might already know. A "gene" is a section of DNA that contains the instructions for making a particular protein. The latest estimates I could find on how many genes flies and humans have are 13,600 for fruit flies and about 20,000 for humans. But most of these genes (for both species) code for ubiquitous proteins that all animals possess. It turns out that the genes themselves are only a small portion of the genomes; 2% maybe. The remaining 98% of the genome consists of DNA that was once thought to be inert or without function. But it is now known that the sections of DNA between the genes contain special regulatory regions, that either promote the production of the protein by the neighboring genes, or inhibit the production of the protein. These regulatory regions control cell differentiation when an embryo develops into an adult animal (all cells in an animal have the same genes, but different genes are turned on or off in different cell types in an animal). So in a sense, the regulatory regions are where much of the action is. Scientists have also learned that the old idea of "one gene one protein" isn't correct; genes can code for multiple proteins. So it turns out that humans have something like 10 times as many kinds of proteins as do fruit flies. One more thing to mention: the human genome is more than 20 times longer than the fly genome. It's unclear how much more of that extra length is functional, but it does seem that merely comparing the genes themselves is missing a huge amount of the picture.
Awesome...thanks!
Do you know how number of genes, length of genome, and number of proteins vary between humans-- and chimps and rhesus monkeys?
From what I read, chimps and humans have genomes that are very similar (96% similar), but with one interesting difference: humans have 23 chromosomes and chimps have 24. It turns out one pair of chimp chromosomes (number 12 and 13) correspond to the human chromosome #2. (That is, our chromosome 2 is essentially the same as the chimp chromosomes 12 and 13 fused together.)
A paper I just Googled up on Science magazine says that rhesus monkeys are 93% similar, and they have 2.7 billion base pairs of DNA. If I'm reading the article correctly, rhesus monkeys have 22 chromosomes (again, they correspond to human chromosomes except for several fusions). I don't know about proteins. I'd have to search some more, but I'm guessing the numbers are much the same for these primates.
I don't think evolution says we evolved from fruit flies and/or pumpkins. My understanding is that we evolved from shared ancestors of both pumpkins and fruit flies.
Can you explain how that happened?
Eric, It appears that you need to take a freshman biology class. This is all basic stuff.
Until then, please lay off discussing science. What you write is down right embarrassing.
Comments from anonymous post-ers are embarrassing! Stand up and be counted!
This comment has been removed by the author.
Sorry...my last comment was too hasty. I got in a hurry!
Unknown, which comment?
The original post was (as I noted) half in jest-- along with some reasonable poking at people who use the percentage of common DNA as some sort of really tight evidence (many of whom have not absorbed Biology 101).
My last post asked for an explanation and (not surprisingly) it was not provided.
An explanation of what? Genes are units of heredity. They can only be inherited and pass down, hence common decent. Homologous genes are genes that share a common origin, such as an ancestor. They may or may not share common activity. That is what biologists mean when they speak about similarities in shared genes. Analogous genes share common activity but not common origin. They may behave similarly, but don't share a common ancestor, i.e. sequencing. The only way we can share sequences with these other organisms is if we inherited them from an ancestor as a source of origin. The vast amount of our DNA regulate and control how the 2% of coding genes operate. For instance, we have a gene for growing tails inherited from our common ancestor, but DNA switches express the genes differently as we grow, as part of regulators responsible for determining if and when we grow certain features. The tail is most prominent in human embryos 31–35 days old.
Evolution only says populations evolve. Changes in the gene pool of populations and lead to new populations. Populations can branch off and undergo their own changes. Changes in a jellyfish-like spineless creature roughly 500 million years ago lead to vertebrate animals. The amphioxus genome experienced two successive DNA doublings, displaying rise to origin of the vertebrates & showing how vertebrates have employed old genes for new functions.
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