Return Home

Leaving Your Lamarck

Back to Episode

Male midwife toad carrying eggs (Laurent Lebois/flickr/CC-BY-2.0)

Jad starts us off with some wishful parental thinking: that no matter how many billions of lines of genetic code, or how many millions of years of evolution came before you, your struggles, your efforts, matter -- not just in a touchy feely kind of way, but in ways that can mold your kids on the deepest level. 

This is, of course, an old idea. Back in the day, Jean-Baptiste Lamarck put forward a theory that animals could pick up traits during their lifetime, through effort and struggle, then pass those traits on to their kids to give them a leg up. So, for example, a blacksmith could bulk up over years of hammering iron, then sire a bunch of thick-armed kids to join the family business. It's a nice thought -- that the hard work you put in could get passed on to your children -- but ... it's wrong. Evolution doesn't work that way. Species change slowly, over long periods of time thanks to chance and fate, with no regard for how an individual improves itself through the course of its life. But is that really the whole story?

Back in the early 1900s, an Austrian biologist claimed he had real-live proof of Lamarckian inheritance in action. Science writer Carl Zimmer and Sam Kean, author of the The Violinist’s Thumb, tell us about Paul Kammerer and his experiments with midwife toads. And what happened when people started to take a close look at his toads.

But it turns out, Kamerer might have been -- perhaps unwittingly -- onto something. Which leads us to a really basic question about parenting -- one that Michael Meaney at McGill University is trying to answer: if you're nice or mean to a kid...what does that actually do to them? Michael, along with Frances Champagne from Columbia University, figured the best way to sort this out was to studying maternal care in rats. It turns out that good rat moms lick their babies a lot. And pups that get licked a lot, go on to lick a lot. You might think they just learn to lick, but Michael and Frances explain to us how a mother's tongue can reach all the way down to their babies DNA.


Image of Paul Kammerer via


Frances Champagne, Sam Kean, Michael Meaney and Carl Zimmer

Comments [23]

Dave from Austin, TX

Lamarck is slowly being shown to have been correct in many respects, epigenetic is paying on of experience from one generation to another. "CRISPR" shows that a cell can "read" an incoming virus intruder, change its own DNA to fend it off... and then pass that sequence change on. This is distinctly Lamarck and has nothing to do with a random mutation (although to be fair that was made up way after Darwin, he never said anything like that).

I edited a very general (sense but all understandable) about the intelligence and intentionality of all living things, which result in their evolution ("Intended Evolution"). Even Darwin thought there was more to evolution than natural selection, he just knew (correctly of course) that natural selection happened, and that was his great contribution.

The last sentence of the introduction to his great work "On the Origins of Species"

"I am convinced that natural selection has been the main but not the exclusive means of modification."
Charles Darwin

May. 14 2017 08:02 PM

The site is not functioning correctly. After sign in is accepted attempts to give a thumbs up to comments here always result in a Login command. Current W10 Chrome used.

Feb. 25 2017 02:21 PM

Check this out! He wasnt crazy after all!!!!!!

Oct. 31 2016 03:12 PM
Rob Conrad from Everywhere

It is my understanding that there is already a genetic pre-disposition for rat mothers to care for their young. That is a part of being a mammal after all. The strands of DNA within cells are constantly under threat of being bombarded with various chemicals. Methyl groups are one of these chemicals and when they hit, they stick very, very well. This happens no matter what. However, when you have a rat pup, which has a genetic disposition to care for it's future young, that has had its DNA covered in sticky methyl groups effectively disabling good mother genes that is then licked by it's mother - you wake up the transcription factors. Transcription factors get "pissed" and surround the DNA proceeding to knock the methyl groups off. :D

Jul. 22 2015 03:59 PM
jessneisha from gray,la

Man that's cool what I'd learn from yall nice and kind people

Jan. 09 2015 09:27 PM

Jake from Brooklyn,
I agree, but suspect that the biochemical and genetic mechanisms commonly cited are not sufficient, despite their huge & relatively unexplored complexity. There are too many questions still unanswered & unasked.

Dec. 16 2014 11:08 AM
jRadioLabb from WDC

Most of the comments presume the shows are just about the 'topic'. To 'get' Jad and the crew, it helps to recognize their purpose as 'advertising' for interesting, possibly powerful, but obscure(d) ideas, which usually deserve much more time and effort at exploration. (some more than others ;))
This article is actually about (mostly) epigenetics; the ways (vastly unknown and unstudied by most scientist, in favor of the more immediately profitable pharmogenetics) that psycho-physiological experience affects our offspring. Although the facts of this article were known 40 years ago, one of the mechanisms (DNA methelation, de/activation) was only explored ~20 years ago, and some of the practical aspects used with the founding of several businesses based on epigenetic manipulation of DNA shape binding methelation points. It is also awesomely complicated by (our ignorance of) the underlying genetics, and a wide and also unstudied 'familial' physiological effects on the nuclear & somatic transcription of nuclear & somatic DNA.
For brevity, I hesitate to also expand on the social, political, or economic implications of this article, but (for one example of dozens?) what happens to our health & life insurance rates in anticipation by actuaries of coming generations of fecund but foreshortened lifespans in obese first world countries.

Dec. 16 2014 10:33 AM
gemeoss from United States

 Quote of the Day and Lyrics in Music

Share our extensive collection of famous quotes by celebrities,authors, newsmakers, and more. Enjoy our Quotes of the Day on the web, blogs, and rede social.

Feb. 22 2014 04:54 PM
Kasler Dominique from Long Island, NY

I also disagree with Jean Baptiste because I feel what your body builds or what you learn is completely up to you. Thats like saying if your parents are strong your going to be strong too, or if they're geniuses your going to be one too. No you have to work hard in all aspects. Those traits aren't passed down in genetics.

Sep. 26 2013 11:18 PM
Josiah Malone from library

The toads and the rats showed how changes in the environment can lead to quick change in the animal or the offspring. The toads developed pad like structures on their feet, while the rats licking had chemical effects on them that chemically stimulated their brain to be the way their parents were. So to simplify it further the mothere licking had chemical effects that altered the way they behave. This caused the rats to be good parents like their mothers were.

Sep. 23 2013 11:32 AM

I agree that the rat pup experiment needed a control group. If, indeed, they did use a control group, it would have been nice to hear about it. Without it, the story did not convince me.

Sep. 12 2013 10:42 AM
Jake from Brooklyn, NY

I was deeply disturbed by this segment. The rat experiment is clearly important, but it does not support Lamarck. Rather, it helps uncover a likely chemical pathway for learned behavior. The rats' nurturing behavior was in their genetic arsenal--it had already evolved--it needed a specific trigger to bring it to the fore.

What should we learn from the rat experience? The divide between "nature" as an inherent and immutable constant, and nurture as a metaphysical power, is inherently false. All of life is chemically based. There is the inherited genome that ultimatly provides the potential--the canvas on which we paint our lives. It is nurture, mediated by objective and material chemical processes, that helps us paint the actual picture of our lives.

Our genetic makup give us many potential "traits" that may require nurture to be expressed. further to Mark F.'s comment, the fact that we learn to read in school is not passed on to our offspring. It is the inherited structure in our brain that is passed on to allow them to achieve the same skills. That structure evolved over millenia.

I am not a scientist, but it seems that the segment blurred the critical differnce between the Darwinian and Lamarckian theories.

Mar. 04 2013 10:26 AM
K. Maier from New York

I want to know what 'overlicking' does. What really needy licking, the "smothering needy mother" kind of licking. how does this change the DNA? Do you becomes really needy unless you are constantly licked? Triggering too much or too little Serotonin can't be good , but you never talk about the other way, usually just deprivation studies are done.

Mar. 02 2013 12:29 PM
sanych from undisclosed location

The segment about Paul Kammerer has some really screwed up timeline (among many other things). It mentions a newspaper article in 1923 about Kammerer travelling around with lectures, and then states that World War I started.


WWI starterd in 1914.

The promoter of Kammerer's ideas in the Soviet Union was Trofim Lysenko, and he came to prominence at least 10 years after Kammerer's death. Lysenko was more of a horticultirist than a biologist. Karl Marx had nothing to do with biology or an idea of a superman. Radiolab could claim with equal effectiveness that Kammerer's ideas were the basis for the Chinese "re-education" camps.

There were many other questionable claims in this segment. For those who are interested, I think this link provides more "balanced" information about Paul Kammerer -

Feb. 15 2013 09:44 AM
Parris Young from Laughing Lady, Montana

I am haunted by failing to remember what led me to suddenly "realize" that, yes, DNA can be altered during one's lifetime. I can 'almost' call it back. When one considers Sheldrake's morphogenic fields, suspicions begin to heap up; if we are dealing with a field instead of just chemical markers with memory, it might be possible to "add a comma", misspell a conjunction, experience a typo, or even, gasp, enter a word.

This might occur because, I believe, again without empirical evidence, that all things carry a constant urge to achieve a higher self. I also believe human beings have been on the edge of an evolutionary leap for a looong time (well, in our terms) ... for instance, the Jesus story is that higher state talking to us.

Jan. 29 2013 08:32 AM
Thorsten from Switzerland

I heard the episode today and was dismayed. It seemed quite anti-scientific - not mentioning a control group for the rats or whether Kammerer's experiments were repeated.
For the former, the answer of EricM in here does not help, IMO. It says nothing about how this "trait" was given to the young rats. I mean, if I teach my children to use a fok, and they one day will teach their children to do so - does anyone believe I altered their DNA?
For the latter, if Kammerer's experiments were as simple and straightforward as the podcast had it, it would be a no-brainer to repeat them. And I'd guess that anyone who had done so successfully would not have hidden the results...
So, a very disappointing episode.

Dec. 17 2012 10:05 AM
Mark F. from Chapel Hill

Jad's notion that he might help his kids "overcome their genes" by good parenting isn't Lamarckian at all. The blacksmith really did give his son big arms, it was just by making him wield a hammer all day rather than by some natal influence. If you thought that these well-educated kids could become sperm or egg donors and the recipients would get the benefits of that extra education; well, that would be Lamarckian.

Dec. 07 2012 10:36 AM

I also came here to ask the same question about what happened if the rat pups were switched. I was curious for somewhat personal reasons. You see, I am the mother of 7 children in a blended family: 2 are my biological sons, 3 are my husband's biological children (including a set of twins), and 2 are genetically unrelated but same-aged children adopted from Kazakhstan. So, my children have 4 completely different sets of genetic parents.

Every day I see before me the dance between genetic and environmental inheritance in my family. I am continually amazed to see my biological sons displaying mannerisms and facial expressions their father had, whom they never knew because he died when they were still in diapers. One of my adopted sons has severe emotional/behavioral problems attributed to Fetal Alcohol Syndrome, Bi-polar disorder, and Reactive Attachment disorder. I ache to think his problems are largely genetic and unlikely to change even though he is in a stable, loving home now.

Dec. 06 2012 09:42 AM

Hasn't someone tried to repeat Kamerer's experiments with the midwife toads? If so, what was the result?

Nov. 29 2012 12:07 PM
Eric M

Tom, Steven, Sara,

I studied this rat experiment in a biology course last year. They actually did switch pups that were not licked to mothers that do lick their pups. I'm not sure why Radiolab didn't mention this one key aspect.

Turns out that when you give pups that aren't licked to mothers that do lick their pups, the pups actually change their behavior in the next generation, and will lick their kids.

Nov. 27 2012 05:28 PM
Sara from Bay Area, CA

Comment-ception: I came here for exactly the reason stevenjklein did: why didn't they switch the babies? I can't believe any of this until that happens. It seems so obvious!

Nov. 27 2012 09:30 AM

I came here to raise the same question that Tom Cronin brings up.

Until they've tried switching pups, how can they be sure that some rats aren't genetically predisposed to exhibit the licking behavior?

Nov. 26 2012 04:48 PM
Tom Cronin from Atlanta, GA

Very curious about any sort of control experiments here. If pups from a non-licking mom are given to and raised by a licking mom, would the licking today reactivate licking behavior when those pups have their own litters?

Also, it was not mentioned in the story whether there are any genetic differences in this population. Do any of the rats actually lack the licking genes, or are they present in all of the rats, and it is just a question of whether they are latent or expressed?

Nov. 20 2012 11:31 AM

Leave a Comment

Email addresses are required but never displayed.