Jacob Tennessen
@jacobphd.bsky.social
Scientist errant. Genetics, evolution, whimsy, awe. https://scholar.harvard.edu/jtennessen
🧬🦟🐌🩸👤🦠🍓🐸🧬
🧬🦟🐌🩸👤🦠🍓🐸🧬
Pinned
Jacob Tennessen
@jacobphd.bsky.social
· Sep 17
Stuff I've written about biology that I think is cool (and you might too):
General musings:
adaptivediversity.wordpress.com
The Emoji Guide to Human Genetic Diversity:
scholar.harvard.edu/jtennessen/e...
More emoji-based science communication:
scholar.harvard.edu/jtennessen/b...
General musings:
adaptivediversity.wordpress.com
The Emoji Guide to Human Genetic Diversity:
scholar.harvard.edu/jtennessen/e...
More emoji-based science communication:
scholar.harvard.edu/jtennessen/b...
Conversation in my mentions about homology between heme and chlorophyll
They did not arise independently. They are both synthesized from protoporphyrin IX, sometimes in the same organism. However, there is no evidence that our microbial ancestors were ever photosynthetic. Plants have heme, but animals do not have chlorophyll. So heme probably came first.
November 26, 2025 at 12:06 AM
Conversation in my mentions about homology between heme and chlorophyll
Frankenstein’s monster, having hidden immortal in the Arctic for 200 years, learns of modern biotechnology and re-enters civilization seeking a path to true humanity. But neither reactionary prejudice nor scientific hubris has changed much in two centuries.
Why isn’t this a movie or graphic novel?
Why isn’t this a movie or graphic novel?
November 25, 2025 at 9:01 PM
Frankenstein’s monster, having hidden immortal in the Arctic for 200 years, learns of modern biotechnology and re-enters civilization seeking a path to true humanity. But neither reactionary prejudice nor scientific hubris has changed much in two centuries.
Why isn’t this a movie or graphic novel?
Why isn’t this a movie or graphic novel?
A painful truth all dads must learn: if you wear a baseball cap while running around on playground equipment designed for children, the brim will block your upper view and you will bonk your head.
November 24, 2025 at 2:05 AM
A painful truth all dads must learn: if you wear a baseball cap while running around on playground equipment designed for children, the brim will block your upper view and you will bonk your head.
I always assumed (probably from the film Chocolat) that passion fruit was named for romantic love evoked by its sultry Latin habitat. Nope. Passion of the Christ.
November 22, 2025 at 3:05 AM
I always assumed (probably from the film Chocolat) that passion fruit was named for romantic love evoked by its sultry Latin habitat. Nope. Passion of the Christ.
Me: What does Lorem ipsum even mean?
Cicero writing the text:
Cicero writing the text:
November 21, 2025 at 3:48 PM
Me: What does Lorem ipsum even mean?
Cicero writing the text:
Cicero writing the text:
I ignore fashion trends. I’m only interested in fashion that’s statistically significant.
November 20, 2025 at 3:01 AM
I ignore fashion trends. I’m only interested in fashion that’s statistically significant.
Reposted by Jacob Tennessen
💥BREAKING: Birds in a tropical pluvial rainforest of the Chocó have been quietly changing in morphology for 109 years. Some have shrunk, others grown. Tails grew longer, bills grew deeper. Even in forests with continuous cover, climate change may be rewriting evolution in real time.
September 29, 2025 at 7:16 PM
💥BREAKING: Birds in a tropical pluvial rainforest of the Chocó have been quietly changing in morphology for 109 years. Some have shrunk, others grown. Tails grew longer, bills grew deeper. Even in forests with continuous cover, climate change may be rewriting evolution in real time.
More cryptic taxa popping up in Anopheles mosquitoes www.biorxiv.org/content/10.1...
Anopheles (Kerteszia) cruzii, the main malaria vector in the Brazilian Atlantic Forest, is a complex of at least five cryptic species
Malaria, a tropical disease caused by Plasmodium and transmitted by Anopheles , remains a public health concern in Brazil. While most cases occur in the Amazon, transmission persists in the Atlantic F...
www.biorxiv.org
November 18, 2025 at 9:20 PM
More cryptic taxa popping up in Anopheles mosquitoes www.biorxiv.org/content/10.1...
Plasmodium parasites, which cause malaria by infecting our blood cells, have no common name. Their ancestors were light-harvesting algae and they still contain the remnants of photosynthetic parts. In effect, they are a seaweed that traded their sea habitat for blood.
So let's call them bloodweeds.
So let's call them bloodweeds.
November 16, 2025 at 10:13 PM
Plasmodium parasites, which cause malaria by infecting our blood cells, have no common name. Their ancestors were light-harvesting algae and they still contain the remnants of photosynthetic parts. In effect, they are a seaweed that traded their sea habitat for blood.
So let's call them bloodweeds.
So let's call them bloodweeds.
New from George Zhang: “Adaptive tracking with antagonistic pleiotropy” as an alternative to the Neutral Theory of Molecular Evolution. Yeast experiments show many mutations are beneficial but rarely fix because environments vary & fitness is highly context-dependent.
www.nature.com/articles/s41...
www.nature.com/articles/s41...
Adaptive tracking with antagonistic pleiotropy results in seemingly neutral molecular evolution - Nature Ecology & Evolution
Population genetics simulations and analysis of experimental datasets in yeast, Drosophila and E. coli show that beneficial mutations are abundant but transient, as they become deleterious after envir...
www.nature.com
November 15, 2025 at 12:02 AM
New from George Zhang: “Adaptive tracking with antagonistic pleiotropy” as an alternative to the Neutral Theory of Molecular Evolution. Yeast experiments show many mutations are beneficial but rarely fix because environments vary & fitness is highly context-dependent.
www.nature.com/articles/s41...
www.nature.com/articles/s41...
New (to me) pop gen tool: GONE (genetic optimization for Ne estimation)—finds very recent population size changes using linkage disequilibrium
academic.oup.com/mbe/article/...
4 ways to install: compiled/to-compile on Mac/Linux. I tried all 4 and all failed. But worked on a different Linux server.
academic.oup.com/mbe/article/...
4 ways to install: compiled/to-compile on Mac/Linux. I tried all 4 and all failed. But worked on a different Linux server.
Validate User
academic.oup.com
November 14, 2025 at 6:12 PM
New (to me) pop gen tool: GONE (genetic optimization for Ne estimation)—finds very recent population size changes using linkage disequilibrium
academic.oup.com/mbe/article/...
4 ways to install: compiled/to-compile on Mac/Linux. I tried all 4 and all failed. But worked on a different Linux server.
academic.oup.com/mbe/article/...
4 ways to install: compiled/to-compile on Mac/Linux. I tried all 4 and all failed. But worked on a different Linux server.
In complex life cycles, selection should act less efficiently in bottleneck stages. Plasmodium parasites go from a few cells at infection to 100s of millions in the blood. Selection strength varies accordingly. Brilliant work by @sarahperkins.bsky.social
royalsocietypublishing.org/doi/10.1098/...
royalsocietypublishing.org/doi/10.1098/...
Heterogeneous constraint and adaptation across the malaria parasite life cycle | Proceedings of the Royal Society B: Biological Sciences
Evolutionary forces vary across genomes, creating disparities in how traits evolve. In organisms with complex life cycles, it is unclear how intrinsic differences among discrete life stages impact evolution. Here, we look for life history-driven patterns ...
royalsocietypublishing.org
November 12, 2025 at 4:41 PM
In complex life cycles, selection should act less efficiently in bottleneck stages. Plasmodium parasites go from a few cells at infection to 100s of millions in the blood. Selection strength varies accordingly. Brilliant work by @sarahperkins.bsky.social
royalsocietypublishing.org/doi/10.1098/...
royalsocietypublishing.org/doi/10.1098/...
Polynesians had domesticated dogs, but none appear in Moana.
The Lion King showcases the biodiversity of Africa but includes no canids (jackals, painted dogs, etc.)
Does Disney practice deliberate dog erasure because people love dogs and they would steal the spotlight from the main characters?
The Lion King showcases the biodiversity of Africa but includes no canids (jackals, painted dogs, etc.)
Does Disney practice deliberate dog erasure because people love dogs and they would steal the spotlight from the main characters?
November 12, 2025 at 4:28 PM
Polynesians had domesticated dogs, but none appear in Moana.
The Lion King showcases the biodiversity of Africa but includes no canids (jackals, painted dogs, etc.)
Does Disney practice deliberate dog erasure because people love dogs and they would steal the spotlight from the main characters?
The Lion King showcases the biodiversity of Africa but includes no canids (jackals, painted dogs, etc.)
Does Disney practice deliberate dog erasure because people love dogs and they would steal the spotlight from the main characters?
You can't win, for I've already drawn you as the disheveled Putative First Animal and myself as the sleek and sophisticated Complex Early Animal.
November 11, 2025 at 5:28 PM
You can't win, for I've already drawn you as the disheveled Putative First Animal and myself as the sleek and sophisticated Complex Early Animal.
This says Anopheles mosquitoes crossed the Atlantic when it was ~2/3 of its modern width, instead of the conventionally stated Mesozoic timing when the distance was short. Is it plausible? Mosquitoes are delicate and absent from many remote islands, but life finds a way…
www.pnas.org/doi/10.1073/...
www.pnas.org/doi/10.1073/...
November 6, 2025 at 11:46 PM
This says Anopheles mosquitoes crossed the Atlantic when it was ~2/3 of its modern width, instead of the conventionally stated Mesozoic timing when the distance was short. Is it plausible? Mosquitoes are delicate and absent from many remote islands, but life finds a way…
www.pnas.org/doi/10.1073/...
www.pnas.org/doi/10.1073/...
Children's book idea: A grocer decides real fruits must have seeds & reorganizes the produce stands. The fruits and veggies are appalled. Zucchinis must leave their carrot friends. Bananas protest. Grape families are split up. Customers are confused. Finally the grocer learns biology isn't identity.
November 6, 2025 at 5:17 PM
Children's book idea: A grocer decides real fruits must have seeds & reorganizes the produce stands. The fruits and veggies are appalled. Zucchinis must leave their carrot friends. Bananas protest. Grape families are split up. Customers are confused. Finally the grocer learns biology isn't identity.
Only one predator species chooses its prey based on what it senses the prey has eaten. Specifically, it wants prey full of human (or other vertebrate) blood! Meet Evarcha culicivora, the spider that prefers blood-fed mosquitoes. Called the vampire spider, but this is misleading: it EATS vampires.
November 6, 2025 at 5:05 AM
Only one predator species chooses its prey based on what it senses the prey has eaten. Specifically, it wants prey full of human (or other vertebrate) blood! Meet Evarcha culicivora, the spider that prefers blood-fed mosquitoes. Called the vampire spider, but this is misleading: it EATS vampires.
Has anyone plotted the runaway inflation of PhD count per fictional character? Who has the most? Ford Pines (Gravity Falls) has 12, Mr Terrific (DC Comics) has 14, Mr Fantastic (Marvel) has 18. At this rate future media will have to give their heroes dozens of PhDs just to make the appear competent.
November 5, 2025 at 8:31 PM
Has anyone plotted the runaway inflation of PhD count per fictional character? Who has the most? Ford Pines (Gravity Falls) has 12, Mr Terrific (DC Comics) has 14, Mr Fantastic (Marvel) has 18. At this rate future media will have to give their heroes dozens of PhDs just to make the appear competent.
Right after 9/11 I lived in the Bronx and taught in Harlem. Some of my sophomores may be grandparents by now. Feeling so hopeful for them and their families as NYC rises and shines.🗽
November 5, 2025 at 2:44 AM
Right after 9/11 I lived in the Bronx and taught in Harlem. Some of my sophomores may be grandparents by now. Feeling so hopeful for them and their families as NYC rises and shines.🗽
Toxoplasma isn't "intelligent" but it manipulates the behavior of rodents & maybe other mammals. A brainless algorithm formed by natural selection to hijack brains.
AI need not know what it's doing either, but versions that engage with human psyche so as to favor their own propagation will prosper.
AI need not know what it's doing either, but versions that engage with human psyche so as to favor their own propagation will prosper.
November 3, 2025 at 3:16 PM
Toxoplasma isn't "intelligent" but it manipulates the behavior of rodents & maybe other mammals. A brainless algorithm formed by natural selection to hijack brains.
AI need not know what it's doing either, but versions that engage with human psyche so as to favor their own propagation will prosper.
AI need not know what it's doing either, but versions that engage with human psyche so as to favor their own propagation will prosper.
The government refuses to end the time change, but they have been willing to adjust what day it occurs. So let's keep pushing the fall back / spring forward days together until Standard Time is just the week between Christmas and New Year's when nobody knows what time it is anyway.
November 2, 2025 at 5:27 PM
The government refuses to end the time change, but they have been willing to adjust what day it occurs. So let's keep pushing the fall back / spring forward days together until Standard Time is just the week between Christmas and New Year's when nobody knows what time it is anyway.
An amusing subreddit to browse is /r/Birdsfacingforward
October 31, 2025 at 6:19 AM
An amusing subreddit to browse is /r/Birdsfacingforward
Parasites as Halloween characters:
Zombie = Naegleria
•Eats your brain
•Once it gets you, no cure
Vampire = Plasmodium
•Feeds on blood
•Reaches victims using flight
Werewolf = Paragonimus
•Associated with canids
•He'll rip your lungs out, Jim
Zombie = Naegleria
•Eats your brain
•Once it gets you, no cure
Vampire = Plasmodium
•Feeds on blood
•Reaches victims using flight
Werewolf = Paragonimus
•Associated with canids
•He'll rip your lungs out, Jim
October 31, 2025 at 2:59 AM
Parasites as Halloween characters:
Zombie = Naegleria
•Eats your brain
•Once it gets you, no cure
Vampire = Plasmodium
•Feeds on blood
•Reaches victims using flight
Werewolf = Paragonimus
•Associated with canids
•He'll rip your lungs out, Jim
Zombie = Naegleria
•Eats your brain
•Once it gets you, no cure
Vampire = Plasmodium
•Feeds on blood
•Reaches victims using flight
Werewolf = Paragonimus
•Associated with canids
•He'll rip your lungs out, Jim
This paper makes for great discussion.
Do I agree with their new definition of domestication? No.
Can I come up with a better one myself? Also no.
www.pnas.org/doi/10.1073/...
Do I agree with their new definition of domestication? No.
Can I come up with a better one myself? Also no.
www.pnas.org/doi/10.1073/...
PNAS
Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans...
www.pnas.org
October 30, 2025 at 3:26 PM
This paper makes for great discussion.
Do I agree with their new definition of domestication? No.
Can I come up with a better one myself? Also no.
www.pnas.org/doi/10.1073/...
Do I agree with their new definition of domestication? No.
Can I come up with a better one myself? Also no.
www.pnas.org/doi/10.1073/...
Wasting away again in Amanitaville
October 29, 2025 at 8:13 PM
Wasting away again in Amanitaville