DNA wrapping and replication : Pharyngula

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PZ Myers is a biologist and associate professor at the University of Minnesota, Morris.
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« Don't watch this, John | Main | It's the arrogance, stupid »

DNA wrapping and replication

Category: Molecular Biology • Science
Posted on: February 14, 2007 12:11 PM, by PZ Myers

I may have to find an excuse to use this in my genetics class—I'll definitely be showing it in my intro biology course in the fall. Very groovy.

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Comments

Posted by: Alric | February 14, 2007 12:19 PM

The DNA replication video is awesome! Although I fear it might become fodder for the IDists.

Posted by: pough | February 14, 2007 12:26 PM

Would it make it less or more ID-friendly if they replaced the machinery sounds with more organic sounds, like squishy farting noises?

Posted by: janet | February 14, 2007 12:28 PM

Amazing. Absolutely amazing. It was produced in 2003 and only now it has found its way to you? What a shame that three years' worth of students didn't have the chance to see this in class.
But then, better late than never.

Posted by: Lynn | February 14, 2007 12:30 PM

The video is awesome. I might take issue, however, with the assertion that "chromosomes aren't always present." Of course they are. They just aren't always condensed enough to see, nor do they always have two chromatids. So while it's correct to say chromosomes in the traditional dense, double structure aren't present all the time, the chromosomes themselves certainly are always there.

Lynn

Posted by: Zuckerfrosh | February 14, 2007 12:32 PM

And creationists say that by taking a god or 'purpose' out of the picture, we fail to see beauty in nature! This is a perfect example of what Dawkins wrote in "Unweaving the Rainbow," that the closer we look, the more we understand, the more beautiful nature becomes.

Posted by: sparc | February 14, 2007 12:40 PM

Chromosomes are not always present. They form around the times cells devide

Either the authors should say 'metaphase chromosomes' or they should replace 'present' by 'visible'. Another issue that is missing is the different directionality of the two strands. Without this knowledge no student will understand the different behaviour of the leading and the lagging strand during replication. An impressive video but still quite a lot of work remaining for PZ.

Posted by: Robster | February 14, 2007 1:07 PM

I'm planning on using this in my classes as well. Youtube has been great for teaching. Nothing like a digital legos kit to show how everything fits together.

Posted by: Doug | February 14, 2007 1:13 PM

Why is the helix so ubiquitous in biophysics, astronomy and probably at the quantum scale?

There surely is some mathematical reason for this, but I doubt that the ID mathematicians are as likely to be as correct as robotic and other engineering applied mathematicians.

See 'Dusty Eye' at Asymtotia
http://asymptotia.com/2007/02/13/dusty-eye/#more-946

Posted by: Teapot | February 14, 2007 1:28 PM

As fast as a jet engine, she said! That means Gawd Al Mitey did it!

#10

Posted by: JW Gibbs | February 14, 2007 1:31 PM

That is a pretty cool video. I would caution your students, however, that the solenoid model for 30nm fiber formation presented in it has pretty much been discarded in favor of the zig-zag model.

#11

Posted by: God Almighty | February 14, 2007 1:36 PM

Why is the helix so ubiquitous in biophysics, astronomy and probably at the quantum scale?

I dig them.

#12

Posted by: Cat of Many Faces | February 14, 2007 1:54 PM

Now, this is why i love biology!

This amazing process, so very beautiful, is going on inside each and every one of us right this moment! billions of times.

that is just so awe inspiring, i don't see why one would need to bring a deity in to spoil it.

On the other hand, maybe i can see where the motivation is. after all, this is such a beautiful thing, so complex and amazing... well, it kinda might make god and all those silly little prayers seem... kinda weak and flat.

unless you follow ERIS, heh.

#13

Posted by: Dedicated Lurker | February 14, 2007 2:06 PM

Sweet!

I want the replication for a screen saver!

#14

Posted by: hephaistos | February 14, 2007 2:20 PM

I see things like this movie and I drop to my knees and thank Athena that I was blessed with the ability to participate, if only in my very small way, in chemistry. Truly there is no greater, no more powerful, and no more useful human endeavor than science. Oh! those poor arts professors!

#15

Posted by: Steve Reuland | February 14, 2007 2:30 PM

Very groovy.

Groan!

#16

Posted by: Stephen Wells | February 14, 2007 2:44 PM

I can think of one reason why helices might be so common: they're actually pretty easy to generate. The basic things that stuff can do is i) go along in a straight line and ii) go round and round. If stuff does both at the same time, presto- helix!

#17

Posted by: Argent23 | February 14, 2007 3:03 PM

@Lynn & sparc: They are correct in that chromosomes are not always present. I know this is often put in textbooks otherwise, but if you want to be precise you can only call the DNA structures in metaphase "chromosomes" (which means "colored bodies") - chromosomes are condensed DNA that is visualised by a dye such as Giemsa.

#18

Posted by: TheBrummell | February 14, 2007 3:43 PM

the chromosomes themselves certainly are always there.

Do mammalian red blood cells no longer count? What about nondisjunction during meiosis?

Also, highly cool videos. My only problem was with sneaking in the obsolete Imperial measurement system. Six feet, indeed. AND that's just humans.

#19

Posted by: David Livesay | February 14, 2007 4:23 PM

Does it really sound like that? Dang! No wonder I can't sleep at night!

#20

Posted by: Ole | February 14, 2007 4:57 PM

I've recently seen this very cool video, The Inner Life of the Cell ( http://www.youtube.com/watch?v=jjexZ88wIno ). It's amazing to see how stuff works (I reckon it's pretty correct). Too bad there's no explanations about it. When I've seen it with friends we've been like: "Oh, that's microtubuli. And there's actin. That must be the Golgi apparatus. Ah, the centrosome."

#21

Posted by: Synkron | February 14, 2007 5:28 PM

Indeed, a student just sent this great vid to me last week after after we went over DNA packing. Though I must admit, initially viewed at low-res it reminded me a lot of what a campy playdoh Corman version of molecular mechanics might look like, with thermal motion simulated by aging tremored hands holding the puppet strings.

BTW, the full version of "Inner Life of the Cell" (8+ minutes with audio commentary) is here. Though very impressive, I like to use it as a jumping off point to motivate discussion on what is presented poorly.

#22

Posted by: MTran | February 14, 2007 6:11 PM

Zuckerfrosh said: the closer we look, the more we understand, the more beautiful nature becomes.

Yes! I will never understand the complaint that science takes away the beauty and majesty of life.

#23

Posted by: John Wilkins | February 14, 2007 6:48 PM

I have to tell you that I have a partial role in this. Drew Berry, the animator, was my staff member when he did this, and I watched it being born. I'm here to tell you this was based on the best science at the time. Drew used the data to set this up, and contacted the scientists whose data he used.

He has a slew of similar videos available for download from

http://www.wehi.edu.au/education/wehi-tv/movies.html

#24

Posted by: Jason | February 14, 2007 8:07 PM

Truly there is no greater, no more powerful, and no more useful human endeavor than science. Oh! those poor arts professors!

Are you pitying the art professors? Who do you think made this artistic visualization?

#25

Posted by: rrp | February 14, 2007 9:17 PM

That's gorgeous, especially the replication.

#26

Posted by: sparc | February 14, 2007 11:21 PM

I know this is often put in textbooks otherwise, but if you want to be precise you can only call the DNA structures in metaphase "chromosomes" (which means "colored bodies") - chromosomes are condensed DNA that is visualised by a dye such as Giemsa.

Are you sure about this? What about the Boveri-Sutton chromosome theory of inheritance developed before 1920? For recent research on chromosomes in other phases of the cell cycle please look here: http://biology.plosjournals.org/archive/1545-7885/3/5/pdf/10.1371_journal.pbio.0030157-S.pdf In addition, other research like telemere maintenance during interphase wouldn't make sense if there weren't chromosomes in other phases of the cell cycle.

What about nondisjunction during meiosis?

There will be still chromosomes altough in aneuploid numbers, e.g. Trisomy 21 in Down syndrome patients.

Do mammalian red blood cells no longer count?

Bullshit question, the progenitors of mammalian red blood cells do have chromosomes. Mature red blood cells do not devide anymore and have a relatively short life span. Thus they can afford the lack of chromosomes.

#27

Posted by: Richard Hendricks | February 14, 2007 11:30 PM

Geez, did anyone even bother to search on the credits? There is a whole website of stuff like this from DNA Interactive:

http://www.dnai.org/index.htm

Most of the 3-D animations are under the Code and Manipulation chapters. See, for example, Code | Copying the Code | putting it together. Another good one is

And I agree, these would make awesome screen savers. This is definitely a site that put alot of thought into what they did.

I just read something in Science that says trimers that code for the same amino acid take different times for the ribosome to attach, causing differences in folding. Maybe they should add that to their animation under Reading the Code? ;)

#28

Posted by: Richard Hendricks | February 14, 2007 11:42 PM

BTW, there are some more 3-D animations in their Inside Cancer website, under Pathways to Cancer:

http://www.insidecancer.org/

#29

Posted by: Scott Hatfield | February 15, 2007 3:16 AM

For those of you who prefer a hardcopy, this animation is available on DVD here. I found it well worth the 19.95:

http://www.carolina.com/biotech/DNA_secret.asp