Critical Section

Archive: June 28, 2003

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Saturday,  06/28/03  12:21 PM

David Burbridge posted an interesting note on GNXP about birth rates.  The key point is that women's average fertility is only one factor in the growth of populations.  (This reminds me that someday I have to get going on Unnatural Selection again...)

Altered CarbonI've been hearing a lot of positive buzz about Altered Carbon, a debut science fiction novel by Richard Morgan.  I'm going to taste it, stay tuned...

The NYTimes reviews iChat AV, Apple's new video conferencing software.  "In iChat AV, video is as crisp, clear, bright and smooth as television."  Man, I'm going to have to try this.  I experimented with video conferencing using Microsoft NetMeeting about three years ago, and it was a total failure.  But it seems like Apple has a winner.

PrintDreams printerAnd here's something cool - the world's smallest printer.  You just wave this handheld device around over a piece of paper, and it prints.  Much like a mouse, it figures out by your movement where it is, and prints accordingly.  Very cool!  {I remember when handheld scanners first came out; it seemed like they wouldn't work, but they did...}

Scoble's not going to join the national "do not call" registry.  So be it.  I did.

I said I was going to leave Echo alone, and I mean to, but Jon Udell posted a must read: Mr conversation with Mr. Safe.  As usual Jon is the man in the middle, considering both sides and shedding light.

Mr. Safe himself [Tim Bray] comments: Stamp out creativity now.

By the way, here's the Echo Wiki itself.  ("Pie" was an early maybe-name, as in "easy as pie".)

BusinessWeek considers the implications of Tivo's monitoring of your surfing habits: A horror show for TV ads.  (As you read this keep in mind that Tivo only reports aggregate behavior, nothing you do is directly monitored.)


Mitochondrial Eve

Saturday,  06/28/03  09:34 PM

Of all the women who have ever lived, there was one woman who was special.  She was the common maternal ancestor of all women currently alive.  She was "Mitochondrial Eve".

Consider the set of all women who have ever lived.  Each had exactly one mother.  Now shrink the set of all women to contain only mothers.  Each of them had exactly one mother.  Shrink the set again to contain only mothers of mothers.  Again, each of these women had exactly one mother.  Again, shrink the set to contain only mothers of mothers of mothers.  Continue doing this until you have a set with exactly one woman.  She is the maternal ancestor of all living women; she is Mitochondrial Eve.

We don't know much about ME.  We do know that she had at least two daughters.  If she didn't have any daughters she couldn't be ME, and if she had only one daughter then her daughter would be ME

mitochondriaThe reason this woman is called Mitochondrial Eve is interesting and significant.  Inside all living cells are structures called Mitochondria, which function as the "power sources" for the cell.  Evolutionary biologists believe that mitochondria were originally separate organisms similar to bacteria, which were "captured" by cells long ago.  Mitochondria have their own DNA, separate from the cells DNA.  All animals inherit their mitochondria and their mitochondrial DNA solely from their mother.  So Mitochondrial Eve is the sole ancestor to a long line of successful mitochondria, and her mitochondrial DNA (mtDNA) is found in all living humans.

Interestingly, geneticists believe that ME lived as recently as 200,000 years ago, based on the observed variation in mitochondrial DNA found in present-day humans.

When ME was alive, she was almost certainly not "the ME".  There would have been other women alive at the same time who would have had different female ancestors.  It is only retrospectively, as a function of the women alive today, that ME is "the ME".  Furthermore, in the future she may again no longer be "the ME"; the entire female line of one of her daughters may die off, leaving one of her daughters or granddaughters or great-granddaughters or ... with the title.

I find it fascinating that it is logically provable that ME existed.  You may too, or you may be thinking "so what?"  But aside from being an interesting concept, akin to "the tallest living man", what else about ME is interesting?  Well, the fact that mtDNA is inherited solely from one parent makes it a simple and interesting way to track variations in human populations.  It is both easier and more accurate than measuring variations in cell DNA.  Assuming that mtDNA mutates with a relatively consistent rate, and given that all living humans had one common mtDNA ancestor (ME), then measuring the average difference between mtDNA samples taken from human populations is a good way to measure the "evolutionary distance" between them.

mtDNA does not necessarily mutate with the same frequency as cell DNA, in fact, most human geneticists feel it probably mutates far less frequently, both because it is genetically "old", and because it only reproduces by fission, leaving less opportunity for "crossing over".  mtDNA therefore provides an interesting "fixed timeline" for comparing potential mutations and mutation rates in cell DNA.

I should mention that some have argued that mtDNA need not mutate with a relatively consistent rate, due to technical reasons involving the mechanisms of mitochondria formation within cells.  If it doesn't it would make mtDNA variation less useful in genetic studies, but it would not mean there was no ME, contrary to arguments others have advanced.

Mitochondria are essential structures in cells, providing as they do the chemical machinery for generating energy.  We can surmise that at one time there was tremendous selective pressure on mtDNA, leading to the present high peak in the valley of fitness.  Because all living humans have a recent common ancestor, they all have similar mtDNA and similar mitochondrial function, and hence there is little selective pressure.  There is evidence to suggest differences in mitochondria may result in differences in human aging.  This would be an important finding if true, leading to much fruitful research, but would not affect selection in the slightest; what is important in selection is how many children you have and when you have them, not how long you live after you have them...

Other than satisfying the definition given above, what was special about ME?  Well - nothing!  She was in all likelihood an unremarkable woman, not especially different from her contemporaries in any significant way.  Her coronation as ME owes as much to luck as to genetic fitness or any other factor.  But just think how much the course of history would have changed had some accident befallen her!  This is the butterfly effect in evolution :)

{By a similar argument, there was one man who was Y-chromosome Adam, the common male ancestor of all men who are alive today...  It is astronomically unlikely that ME and YA were contemporaries, and even more unlikely that they knew each other or mated together.}

[ This post owes much to Daniel Dennett's classic book, Darwin's Dangerous Idea. ]

[ Later: this post attracted a bunch of interest - thank you! - and several people asked a key question: what species was ME? ]


Saturday,  06/28/03  10:07 PM

Sci-Fi Hi-Fi: Apple DRM Revisited.  Or how the Apple Music Store protects the music they sell so it isn't easily pirated...

The Electronic Frontier Foundation responds to the RIAA's plans to sue individual users for file sharing: "It's plain that the dinosaurs of the recording industry have completely lost touch with reality."  Yep.

Harry PotterSlate: Harry Potter and the International Order of Copyright.  How long do you think it will be before we'll all be able to print our own books?  Then digital rights management will be necessary for books, too...  Right now it is just intellectual property, because the barriers to duplication are a bit high.

And speaking of digital information media (we were, right - music and books...), InfoTrends predicts that digital photography will completely replace film by 2008.  [ via Ottmar Liebert, who seems to blog about many of the same things I find interesting! ]

So when do you think digital video will replace analog film in movie theaters?  Within ten years, I would guess.  And that will have its own set of DRM issues!

Boy I said I would leave Echo alone, but it won't leave me; Scoble has a long rant about Dave Winer and the goodness of RSS.  I sure hope there's more to RSS than separating RSS from Dave!

We have the NYTimes and Microsoft and CNet and now we even have Oracle supporting RSS, why do we have to go change it?  Why can't it be evolved?  Just because of some API problems?  Sheesh.

Brian Keller says "Whidbey is going to rock".  Whidbey is the code name for the next version of Visual Studio, for which Brian is the program manager.  That's great - I use VS every day, so this will really matter to me, but...  This is the bad thing about all these developers having blogs; they tease you by telling you how cool everything is, but their companies won't let them tell you why.  I say either tell us why Whidbey or Longhorn or whatever is going to rock, or don't say anything.

Psst!  Want to be an A-list blogger?  Then the Internet Pundit Fantasy Camp is for you.  Satire is best when it runs close to truth, eh?  (Or is this really truth?)


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About Me

Greatest Hits
Correlation vs. Causality
The Tyranny of Email
Unnatural Selection
Aperio's Mission = Automating Pathology
On Blame
Try, or Try Not
Books and Wine
Emergent Properties
God and Beauty
Moving Mount Fuji The Nest Rock 'n Roll
IQ and Populations
Are You a Bright?
Adding Value
The Joy of Craftsmanship
The Emperor's New Code
Toy Story
The Return of the King
Religion vs IQ
In the Wet
the big day
solving bongard problems
visiting Titan
unintelligent design
the nuclear option
estimating in meatspace
second gear
On the Persistence of Bad Design...
Texas chili cookoff
almost famous design and stochastic debugging
may I take your order?
universal healthcare
triple double
New Yorker covers
Death Rider! (da da dum)
how did I get here (Mt.Whitney)?
the Law of Significance
Holiday Inn
Daniel Jacoby's photographs
the first bird
Gödel Escher Bach: Birthday Cantatatata
Father's Day (in pictures)
your cat for my car
Jobsnotes of note
world population map
no joy in Baker
vote smart
exact nonsense
introducing eyesFinder
to space
where are the desktop apps?