Radiolab: "Funky Hand Jive" (April 26, 2017)
Main Theme
This episode of Radiolab explores the science of the human microbiome—specifically, whether the microbes from a famous handshake (JFK and the young Robert Krulwich) could linger, and what a handshake really transfers between two people. Through a mix of storytelling and experiment—with scientists, physicians, and guest star Neil deGrasse Tyson—the hosts dig into questions of microbial individuality, lifelong microbial inheritance, and the cutting-edge forensic and health science developing around our personal clouds of bacteria.
Section Summaries & Key Discussion Points
1. A Presidential Handshake and its Microbial Echo
[01:49–04:15]
- Robert Krulwich recounts shaking President John F. Kennedy’s hand as a teenager and wondering—half-jokingly at the time—whether some essence of JFK would linger on his own hand.
- This becomes the seed for the central question: Can a handshake leave microbes that stick around for days, weeks, or even years?
"At the moment, I thought, oh, Kennedy on Robert."
—Robert Krulwich [03:58]
2. Meet the Scientists & The Big Experiment
[05:00–14:16]
- Robert, unable to shake JFK’s hand again, enlists scientists (notably Jack Gilbert from the University of Chicago), a team from WNYC’s Only Human, and astrophysicist Neil deGrasse Tyson as JFK's stand-in.
- The experiment: Swab Neil and Robert’s hands pre-handshake, perform handshake, swab at intervals post-handshake, and analyze the bacterial transfer.
Microbial Introduction:
- Humans are "covered with germs," but each of us carries a unique "microbial fingerprint."
- Jack Gilbert describes every mucosal surface and all skin as host to billions of bacteria, with people each shedding 36 million bacterial cells an hour into their environment.
"Think Pig Pen from the Peanuts cartoon...about 36 million bacterial cells an hour."
—Jack Gilbert [07:23]
- Even chairs are covered with each sitter’s unique mix, especially from our "colonic" bacteria—aka, yes, a little bit of poop.
Control, Execution, and Swabbing:
- Jack Gilbert: "So we have these little sterile tubes... we're going to open that up and very quickly rub very vigorously each of your hands." [09:08]
- Discussion covers why people develop unique microbial signatures—distinct even for city dwellers, as primary composition is inherited at birth, chiefly from the microbiome of our mothers.
3. Microbial Baptism and the Founder Effect
[10:33–14:16]
- Dr. Siobhan Dolan (OB/GYN) describes the "bacterial baptism" babies undergo during birth and skin-to-skin contact with their mothers—which sets their lifelong microbial signature (the "founder effect").
- These primary microbes outcompete later arrivals, shaping everything from gut health to disease risk.
"The bacteria, they're like, give me a ride. I'm gonna jump on."
—Dr. Siobhan Dolan [11:28]
- Even if you try to sterilize your system or move across the globe, much of the original microbial cohort resurges due to the founder effect.
4. The Handshake Experiment—Method and Anticipation
[14:16–15:14]
- Neil deGrasse Tyson and Robert perform the handshake, after pre- and post-swabbing by Jack Gilbert, who narrates.
- Jad and Robert recap, teasing the results after a break.
"Two hands coming together...It's like taking a rainforest from Bolivia and dumping it on top of a rainforest in Brazil and wondering whether any of the trees from the Bolivian rainforest will take root..."
—Jack Gilbert [25:31]
5. From Microbial Forensics to Disease—The New Science
[19:32–21:20]
- Jack discusses emerging applications:
- Forensics: People leave enough microbial trace that, after spending 15 minutes in a space, they can be identified among several suspects half an hour later.
- Public Health: Sewer microbiome monitoring could preemptively reveal outbreaks before visible illness.
"If somebody comes into a room and does an evil deed...we could detect which one of them had broken into that room."
—Jack Gilbert [20:04]
- Microbiome differences also play potential roles in medicine, from predicting drug reactions to personal disease risk.
6. Revealing the Handshake Results—Surprise!
[21:21–26:16]
- Anticipation: Jack predicted a little transfer of bacteria, disappearing quickly.
- Result: Contrary to expectations, Robert transferred a large, persistent dose of his microbes to Neil—but Neil left almost none on Robert.
"It was zero....Actually they found a teeny number of bacteria, but they died."
—Robert Krulwich with Jack Gilbert [22:22–22:33]
-
Neil’s hand picked up Robert's bacteria, causing “quite a substantial disruption” and their persistence for over 20 minutes ("could have gone on ad infinitum" [24:52]).
-
Jack theorizes a stray streptococcus bacterium from Robert’s hand disrupted Neil’s microbiome, clearing the way for colonization.
"There was a streptococcus that was very abundant on your hand at the beginning, that was transferred to Neil's hand. And we see that transfer occurring. And that Streptococcus somehow disrupted Neil's ecosystem and allowed for a greater transfer of bacteria from your hand to his hand."
—Jack Gilbert [26:42]
- The outcome was "atypical": normally, "your bacteria have home field advantage...the invading microbes start to die."
7. Reflections, Banter, and Takeaways
[27:08–29:38]
- The hosts and Neil riff humorously on invasive microbes, personal hygiene, and strange pride (and embarrassment) in Robert’s “victory.”
"My microbiome was perfectly content staying where it is. And apparently Robert's microbiome can't wait to get the hell off his body."
—Neil deGrasse Tyson [27:40]
-
The central question (“Did JFK stay on me?”) morphs: perhaps the real curiosity is around how long Robert stuck to Neil.
-
Conversation ends with playful ribbing about “creepy, sweaty” hands and “something’s gotta give” (song clip).
Notable Quotes
- Robert Krulwich: "I said to my sister, I shook President Kennedy's hand, and I guess I'm not gonna wash it for, like, two days, two weeks, maybe." [03:36]
- Jack Gilbert: "You have a lifelong partnership with the bacteria you interacted with." [13:38]
- Neil deGrasse Tyson: “No, there's no part of anyone else that I just want to purport.” [06:01]
- Jad Abumrad: "I'm slightly proud and kind of troubled." [24:24]
- Jack Gilbert: “It’s like taking a rainforest from Bolivia and dumping it on top of a rainforest in Brazil and wondering whether any of the trees ... will take root...” [25:31]
Key Timestamps for Important Segments
- [01:49] – Robert describes the original Kennedy handshake story
- [04:15] – Scientific framing: can microbes persist from a handshake?
- [05:00] – Introduction of experiment, Neil deGrasse Tyson steps in
- [07:23] – Jack Gilbert explains our microbial “cloud”
- [10:33] – Dr. Siobhan Dolan on “bacterial baptism” and mother-to-baby microbiome transfer
- [13:36] – Founder effect and lifelong microbial inheritance
- [14:16] – Handshake experiment, swabbing, and sampling
- [19:32] – Forensic and public health implications of the microbiome
- [21:21] – Experiment results: only Robert's bacteria stuck
- [24:13] – Analysis of why the results were so lopsided
- [25:31] – "Rainforest on rainforest" analogy
- [27:40] – Neil on his microbiome's defensiveness
- [29:06] – Closing banter and reflection
Memorable Moments
- Neil’s good-natured skepticism and humor throughout (e.g., "No, I'm not that weird or creepy." [05:55])
- Jad’s mix of pride and disturbance at Robert’s “microbial dominance” [24:24]
- The surprise at scientific unpredictability: the experiment didn’t go as expected, highlighting how little is still known about microbial ecosystems.
Episode Flow and Tone
- Tone: Curious, playful, and deeply nerdy—filled with characteristic Radiolab banter, analogies, and sound effects.
- Structure: Begins with a personal story, moves to sci-journalism and experiment, and ends reflecting on the experiment’s surprise results and their implications.
Bottom Line
"Funky Hand Jive" uses a quirky, personal experiment to illuminate the profound role our microbiome plays in identity, inheritance, and health—and how even the briefest contact, like a handshake, can reveal the shifting, competitive, and sometimes unpredictable drama of our tiny microbial passengers.