Breast beginnings

Posted 19 May 2006 by PZ Myers

Four of my favorite things are development, evolution, and breasts, and now I have an article that ties them all together in one pretty package. It's a speculative story at this point, but the weight of the evidence marshaled in support of the premise is impressive: the mammalian breast first evolved as an immunoprotective gland that produced bacteriocidal secretions to protect the skin and secondarily eggs and infants, and that lactation is a highly derived kind of inflammation response. That mammary glands may have had their origin as inflamed glands suppurating mucus may not be the most romantic image to arise in a scientific study, but really—they got better and better over the years.

Continue reading "Breast beginnings" (on Pharyngula)

42 Comments

Sounder · 19 May 2006

Now this is a topic that I can get my hands on!

Steve Harrynuk · 19 May 2006

"Four of my favorite things are development, evolution, and breasts..."

That's only three things. Unless you mean the left breast and the right breast.

Carsten S · 19 May 2006

Steve, you might not have noticed it, but you have found the joke.

Glen Davidson · 19 May 2006

Though to tell the truth, two is not necessarily the number of perfection. Multiples of two, yes....

Glen D
http://tinyurl.com/b8ykm

KC · 19 May 2006

"Milk is actually a kind of anti-microbial snot mixed in with a lot of fat and sugar."

Brilliant.

FL · 19 May 2006

Here is another perspective concerning breast milk and its origins:

http://www.icr.org/index.php?module=articles&action=view&page=388

"Design in Infant Nutrition", by Rex D. Russell, M.D.

****************************

Jeremy Mohn · 19 May 2006

By definition, evolutionary scientists believe that life came through random chance processes, including natural selection.
— The author of FL's article

Sorry, FL, I didn't make it past this first sentence. Anyone who refers to natural selection as a "random chance process" has no business criticizing evolution.

Steviepinhead · 19 May 2006

FL could think all day, and think all night, and still never get past his preconceptions. Rather than viewing PZ's post as helpfully answering--or at least usefully beginning to tackle the task of filling in--the gaps in knowledge emphasized by FL's own cough cough "expert," FL of course prefers to remain in ignorant bliss, and treat the two articles as just offering us arguably-comparable "perspectives."

When, of course, one is the product of a yammering ninnyhammer, while the other is the product of actual scientific effort. One, at best, identifies a potential area of inquiry, but then forever defers the pursuit of that inquiry. The other rolls up its sleeves, works up some sweat, and gets inquiry done.

These approaches represent two equivalent "perspectives" only when viewed sideways in a funhouse mirror. Viewed through clear glass, rather than FL's stained-glass blinders, FL's preferred approach is like gazing up at the steeple and saying, "Dang! That sucker shore is high! Sure wouldn't have to replace the shingles on that baby!" While the scientific approach is much more like, "Yep, that's a pretty tall steeple, but those missing shingles aren't gonna replace themselves. Lenny, you go get the scaffolding! PZ, you go grab the extension ladder! Raging Bee, would you please fetch the climbing gear? Oh, and don't forget the locking carabiners!"

FL, wouldn't you find the world a much more interesting place if you either pitched the blinders entirely, or at least reserved them for special Sunday-only use? How does it please the Almighty for you to deliberately benight yourself in this manner? Not to mention turning your back on the messages She has writ so clearly for you in Her creation?

Bill Gascoyne · 19 May 2006

[Lactose] is a sugar that many bacteria have difficulty digesting (it's not just people that can be lactose intolerant!)

Actually, IIUC, lactose tolerance is a European mutation, and it is rather Eurocentric to speak of lactose intolerance. (Please correct me if I'm wrong.)

Steviepinhead · 19 May 2006

Because we're speaking of infant nourishment, perhaps it's appropriate to speak of lactose tolerance as the general and intolerance as the special case.

Among adults, of course, Bill Gascoyne is corrent that it's the other way around.

The supposition is, as I understand it, is that domestication of milk-bearing animals (probably first sheep and goats, then later bovids) was part of the cultural toolkit that accompanied the Indo-European speakers as they spread into Europe, and this availability of an ongoing (secondary) supply of milk products likewise favored the spread of lactose tolerance among adults.

c · 19 May 2006

Since we're already on the subject of the evolution of breasts, it's not a great leap for me to ask a question about sexual reproduction. I recently saw a species of lizard on Animal Planet that does not have any males and the females reproduce asexually. In order to do this though, the female must be mounted by another female to simulate sex. The program then went on to say that the Y chromosome in humans has degraded and now has far fewer genes than the X chromosome, and the Y chromosome may disappear completely. My understanding is that sexual reproduction evolved as it allows a species to evolve and adapt to change more rapidly. How, then, is it beneficial to revert back to asexual reproduction? And if asexual reproduction is that beneficial, why evolve sexual reproduction in the first place?

Henry J · 19 May 2006

Re "Actually, IIUC, lactose tolerance is a European mutation, "

Really? Then it's not just orientals that often can't take milk, but Africans and maybe middle easterners too?

Re "My understanding is that sexual reproduction evolved as it allows a species to evolve and adapt to change more rapidly. How, then, is it beneficial to revert back to asexual reproduction?"

My guess is that if things stay stable for a long time, asexual repro. saves energy. It also quite likely puts that lizard species in a precarious situation - if environment starts changing quickly again it's in trouble.

Henry

FL · 19 May 2006

Sorry, FL, I didn't make it past this first sentence. Anyone who refers to natural selection as a "random chance process" has no business criticizing evolution.

Well, let's go back to that first sentence you failed to, umm, make it past.

"By definition, evolutionary scientists believe that life came through random chance processes, including natural selection."

You could have simply said that Russell was incorrect to say the phrase "...including natural selection" at the end of his statement there, and then continued on reading the artilce. After all, ~other than the last three words~, Dr. Russell's statement is quite correct.

"Evolution certainly does involve randomness; it does involve unpredictable chance." ---Douglas Futuyma

So that leaves the obvious question. Why stop reading at the first sentence? How can you or I be in a position to pre-judge an article that (minus the first sentence) you've not even read? Mmm. Don't think so. ****************

FL, wouldn't you find the world a much more interesting place if you either pitched the blinders entirely, or at least reserved them for special Sunday-only use? How does it please the Almighty for you to deliberately benight yourself in this manner? Not to mention turning your back on the messages She has writ so clearly for you in Her creation?

Interesting questions, yes, but not a one of them actually addresses the specific points made in Dr. Russell's article. It's as if, like Jeremy, you didn't bother to read and think through the article. Mmm, once again. Honestly, the idea here was--and is--to simply offer another perspective on the topic at hand. Readers can then read 'em both, compare 'em both, ~think about~ them both, and then draw conclusions one way or the other; that does not bother me. I trust that does not bother you either? FL

'Rev Dr' Lenny Flank · 19 May 2006

breast

Hey FL, isn't it sinful for you to use that word? Don't you need to go pray for forgiveness or flagellate yourself or something now? Heavens to betsy, next thing you know you'll be talking about DANCING.

'Rev Dr' Lenny Flank · 19 May 2006

Well, we've had Donald's driveby, and now FL's driveby. By the way, FL, now that you're here, you forgot to answer a simple question for me last time. *ahem* If, as you so loudly declared, ID isn't creationism, then why does the Discovery Institute's Center for (The Renewal of (Science and Culture list, in its Wedge Document, as one of its "FIVE YEAR OBJECTIVES":

* Major Christian denomination(s) defend(s) traditional doctrine of creation

What exactly is this "traditional doctrine of creation" that DI wants "major Christian denominations" to "defend"? It's a simple question, FL. Why are you so reluctant to answer it?

'Rev Dr' Lenny Flank · 19 May 2006

After all, ~other than the last three words~, Dr. Russell's statement is quite correct.

So his statement is correct, uh, except for the parts that are incorrect. Got it. That's about the level of argument I've come to expect from creationists.

steve_h · 19 May 2006

Milk is actually a kind of anti-microbial snot mixed in with a lot of fat and sugar.

Black will be fine.

B. Spitzer · 19 May 2006

c wrote:

My understanding is that sexual reproduction evolved as it allows a species to evolve and adapt to change more rapidly. How, then, is it beneficial to revert back to asexual reproduction? And if asexual reproduction is that beneficial, why evolve sexual reproduction in the first place?

You've put your finger on an old, intractable question. Yes, one of the advantages of sex is supposedly its ability to adapt more rapidly, giving sexuals the edge against pathogens. It's also been suggested that sexuals can purge their population of harmful mutations, while asexuals, unable to go through recombination, must accumulate tiny harmful mutations until they die the extinction of a thousand cuts. There's a lot of discussion about which of these mechanisms (or some other) might explain sex, which is an incredibly inconvenient way to pass on one's genes, if you stop and think about it. The advantages to asex (yeah, they call it that) are that you're passing on your whole genome, not just half of it, to each offspring, and you don't have to carry the procreational dead weight of those sexual parasites known as "males". When population densities are low, asexuals can crank out clones at twice the rate of a sexually-reproducing organism. Weirdly, as your post implies, there are lineages that have gone back and forth from sexual to asexual. Within the scale insects, for example, there are taxa that have tried out every funky way of passing on genes that they can come up with. There are even some very, very old asexual lineages (rotifers spring to mind), which is bizarre-- you'd expect one group, sexuals or asexuals, to take over completely, but that doesn't seem to be happening. There's been some really neat work on this subject... there are in fact quite a few asexual "species" that, like your, um, lesbian lizards, spun off relatively recently from a sexual population. I'm thinking particularly about a lake full of snails in New Zealand-- there are both sexual and asexual snails, and the sexuals dominate the areas where pathogens are more common. Life. It's so weird. By the way, there's a quite entertaining book by Olivia Judson (I think), entitled "Dr. Tatiana's Sex Guide for All Creation". It has some fascinating examples in it and is a fun read. I apologize if I'm going too far off-topic with this post, by the way.

Steviepinhead · 19 May 2006

Uh, FL, I did read the article, although one containing an elementary error--one which was in all likelihood a deliberate distortion--in its first sentence didn't really deserve the effort, as has been pointed out above.

Predictably, the article enumerates the wondrously-"complex" mix of substances which seem so perfectly "designed" to nourish young mammals. And gets stuck right there. No effort to figure out how this combination of substances arose. No effort to figure out what other bodily secretions or hormonal signals the breast milk "system" most closely resembles. Just the usual creationist drivel (er, pablum): it's too complex and amazing to have arisen naturally, so--Lawdy to Betsy!--it must have been a gift from above!

Ain't that the gist?

Even a needle must get weary of running around in the same old rut. But not FL...

khan · 19 May 2006

I doubt the article addresses having to tie them into a square knot to keep them off the floor.

Tyrannosaurus · 19 May 2006

FL The Clueless dribbled
After all, ~other than the last three words~, Dr. Russell's statement is quite correct.

Well here we go again. Why do this dumbbells who have no notion whatsoever of logic or simple rules try to teach everyone else?
Listen Dumbo, a statement is correct or incorrect. Once you make a part of it incorrect the whole premise becomes incorrect or false. Get it.

Tyrannosaurus · 19 May 2006

FL The Clueless dribbled
After all, ~other than the last three words~, Dr. Russell's statement is quite correct.

Henry J · 19 May 2006

Re "so---Lawdy to Betsy! --- it must have been a gift from above!"

Milk evolved from manna? ;)

Henry

Sir_Toejam · 20 May 2006

From the summary of the article posted by FL:

In this article, we will see that the more the human breast and its milk are studied, the more obvious it is that neither random chance nor survival of the fittest could explain their design and complexity.

now milk is irreducibly complex?? what about skim milk?

Anton Mates · 20 May 2006

Skim milk represents loss of information, silly. Fatty information.

Vyoma · 20 May 2006

Here is another perspective concerning breast milk and its origins:
— FL

Great... thank you for providing the other perspective, the incorrect one, as a balance to the well-researched an peer-reviewed correct perspective. I applaud your valiant crusade to make sure that poorly considered opinions are brought to our attention as cautionary examples so that science can continue to progress. I'm looking forward to your provision of a comprehensive list of links regarding phlogiston at some point in the near future.

Vyoma · 20 May 2006

now milk is irreducibly complex??
— sir_toejam

Everything is irreducibly complex. A glass of milk no longer functions if you remove half the milk, you know.

Moses · 20 May 2006

Comment #101425 Posted by Bill Gascoyne on May 19, 2006 03:12 PM (e) [Lactose] is a sugar that many bacteria have difficulty digesting (it's not just people that can be lactose intolerant!)

Actually, IIUC, lactose tolerance is a European mutation, and it is rather Eurocentric to speak of lactose intolerance. (Please correct me if I'm wrong.) Lactase is an enzyme that virtually all babies possess in sufficient amounts to digest milk, but except for those who carry a beneficial mutation originating in Northern Europe, the production of this enzyme decreases as you get older (just like most other mammals). What I learned was that you are not so much as being "intolerant," but were actually going through the normal process of becoming increasingly lactase deficient. If you take lactase pills, you can, once again, eat lactose containing foods without a consequence. Whereas, if you were truly intolerant, you'd still have some kind of reaction.

Bob O'H · 20 May 2006

Actually, IIUC, lactose tolerance is a European mutation, and it is rather Eurocentric to speak of lactose intolerance. (Please correct me if I'm wrong.)

Isn't wiki great: it has a whole article:

There is some debate on exactly where and when the mutation(s) occurred, some arguing for separate mutation events in Sweden (which has one of the lowest levels of lactose intolerance in the world) and the Arabian Peninsula near 4000 BC which converged as they spread, while others argue for a single event in the Middle East at about 4500 BC which radiated from there. Some sources suggest a third and more recent mutation in the East African Tutsi.

Bob

stevaroni · 20 May 2006

...the Y chromosome in humans has degraded...

You know, it's funny, but my wife makes the exact same observation, and as far as I know she's never even been near a microbiology lab. Hmmm....

Jeremy Mohn · 20 May 2006

So that leaves the obvious question. Why stop reading at the first sentence?
— FL

Because I have better things to do than read an article by someone who thinks natural selection is a "chance random process." *-shrug-*

How can you or I be in a position to pre-judge an article that (minus the first sentence) you've not even read?
— FL

I only commented on the first sentence. I was not judging the entire article. However, as far as I am concerned, an article pre-judges itself when it contains a fundamental error in the first sentence. But your question is a good one, FL. How can anyone be in the position to pre-judge a document when he or she has only read bits and pieces of it? Who - would - ever - do - such - a - horrible - thing - ?

Sir_Toejam · 20 May 2006

you might want to mention Behe's comments in his Dover testimony about why he didn't need to read any of mountains of papers presented to him, as well.

hey FL!

Why did Behe feel he could dismiss 15 years of research with a wave of his hand, eh?

think he ever read more than the first sentence of any of those PUBLISHED papers?

Get a clue, would ya? there's nothing more to your "philosophy" that simple projection.

AC · 22 May 2006

You could have simply said that Russell was incorrect to say the phrase "...including natural selection" at the end of his statement there, and then continued on reading the artilce. After all, ~other than the last three words~, Dr. Russell's statement is quite correct.
— FL

Other than the last three words, the statement is still incorrect, because it defines evolution as exclusively the result of "random chance processes". Tacking "including natural selection" on the end is merely a further revelation of ignorance. Also, "random chance processes" is redundant.

lamarckiantits · 23 May 2006

Am I the only one that smells Lamarck here? isnt an inflamed gland like a well developed muscle of sorts? the immunological reaction became genetically stabilized

Lauren · 2 June 2006

No... God created man and woman in God's own image and out of man and woman was God's perfect plan, God's ultimate desire. We are created and wonderfully and fearfully made. The developement now of the sexual processes have to be so perfect that a designer had to have created them. Oh or else you can keep beleiving in sheet dumb luck having evolved all these things randomly, but God was the designer of all things and that is why all things share a similar body plan and similar features, not because of some random chance event having happened millions of years ago and then here we are, plus DNA is so slow to have evolved now that mutations are not even proveaable and it should not even be here yet scientifically speaking by how slow it takes to even be here! Medell, the father of genetics once said. Anyway, God is who made breasts and for a reason, an obvious one granted. hhahaha -lou

Anton Mates · 2 June 2006

plus DNA is so slow to have evolved now that mutations are not even proveaable and it should not even be here yet scientifically speaking by how slow it takes to even be here! Medell, the father of genetics once said.
— Lauren

Mendel died about sixty years before DNA was established as the material of heredity.

Sir_Toejam · 2 June 2006

boy, we sure seem to be getting a lot of creobots lately.

what's up with that?

Anton Mates · 2 June 2006

Oh well, might as well go through the rest.

No... God created man and woman in God's own image and out of man and woman was God's perfect plan, God's ultimate desire. We are created and wonderfully and fearfully made.
— Lauren

Okay. Any particular reason why God couldn't have realized his/her/its perfect plan and ultimate desire through the evolutionary process?

The developement now of the sexual processes have to be so perfect that a designer had to have created them.

I don't think most women who've been through labor (or men who've had an inguinal hernia, or women who've had breast cancer) would really acclaim the perfection of the human reproductive process. Heck, Genesis explicitly says some of its unpleasantnesses are a curse from God.

Oh or else you can keep beleiving in sheet dumb luck having evolved all these things randomly,

Natural selection isn't random.

but God was the designer of all things and that is why all things share a similar body plan and similar features,

Would you say that, for instance, rocks and nebulae and quasars and neutrinos share a similar body plan with humans and ferns and frogs? If not, does that mean God didn't make them? More generally, how does the "common design implies a common designer" argument deal with patterns of similarity? We resemble chimps more closely than either of us resembles parrots, and all of us resemble one another more than we resemble centipedes. Does that mean that God made us and chimps, God's brother made centipedes, and they worked together on parrots?

not because of some random chance event having happened millions of years ago and then here we are, plus DNA is so slow to have evolved now that mutations are not even proveaable and it should not even be here yet scientifically speaking by how slow it takes to even be here!

Are you saying that you don't actually believe that random events and mutations occur? What about, say, cancer?

Anton Mates · 2 June 2006

Oh well, might as well go through the rest.

No... God created man and woman in God's own image and out of man and woman was God's perfect plan, God's ultimate desire. We are created and wonderfully and fearfully made.
— Lauren

Okay. Any particular reason why God couldn't have realized his/her/its perfect plan and ultimate desire through the evolutionary process?

The developement now of the sexual processes have to be so perfect that a designer had to have created them.

Oh or else you can keep beleiving in sheet dumb luck having evolved all these things randomly,

Natural selection isn't random.

but God was the designer of all things and that is why all things share a similar body plan and similar features,

not because of some random chance event having happened millions of years ago and then here we are, plus DNA is so slow to have evolved now that mutations are not even proveaable and it should not even be here yet scientifically speaking by how slow it takes to even be here!

Are you saying that you don't actually believe that random events and mutations occur? What about, say, cancer?

Anton Mates · 2 June 2006

Apologies for the double post.

Sir_Toejam · 2 June 2006

(or men who've had an inguinal hernia...

or gallstones (ouch!) or kidney stones (ouchier?).

steve s · 2 June 2006

Comment #103583 Posted by Sir_Toejam on June 2, 2006 04:25 PM (e) | kill boy, we sure seem to be getting a lot of creobots lately. what's up with that?

And low-rent ones, too, like AFDave and Larry Farfarafarman. I'd just be happy for some with average intelligence.