The Insane Biology of: The Axolotl

Real Science

16 Oct 202121:02

EducationalLearning

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TLDRThe axolotl, a salamander species once revered by the Aztecs, possesses an incredible ability to regenerate limbs, organs, and parts of its brain. With populations on the verge of extinction in Mexico's Lake Xochimilco due to pollution and habitat loss, axolotls now thrive most abundantly in labs and aquariums worldwide where scientists study their regenerative superpowers hoping to one day harness them for human medical benefit. However, without greater genetic diversity and a restored natural habitat, the long term survival of this magnificent 'water monster' remains under threat.

Takeaways

😲 The legend of the Five Suns is the Aztec creation myth, with the Fifth Sun bringing humans into existence
😯 The god Xolotl transformed into an axolotl to avoid being sacrificed, leading it to be seen as a god in animal form
🤔 Axolotls uniquely stay in larval form their whole lives and can regenerate limbs, organs, parts of eyes/brain
🔬 Studying axolotl regeneration has greatly furthered medicine and biological knowledge over centuries
😮 Axolotls can regrow parts of their brains, contrasting mammals that cannot regenerate neurons as adults
😀 Key molecules for axolotl regeneration are also in humans, suggesting latent abilities that could be unlocked
😥 The axolotl is nearly extinct in the wild due to Mexico City urban expansion and polluting/draining Lake Xochimilco
😕 Captive axolotls lack genetic diversity so simply reintroducing them could fail without improving habitats
🤞 Scientists hope newly established habitats like abandoned quarries may sustain captive-bred axolotl populations
🌎 Mexico has incredibly high biodiversity, with over 10% of Earth's species, but habitats like grasslands need protection

Q & A

Why did the axolotl evolve to keep its juvenile form?
-The axolotl and other salamanders in the Mexican lakes evolved to keep their juvenile form likely because the lakes provided a stable aquatic habitat without predators, surrounded by dry desert terrain. Retaining juvenile traits allowed them to stay in the safety of the water.
Can axolotls transform into their adult form?
-Yes, axolotls can transform into their adult, terrestrial form if given thyroid hormone or forced to breathe air for an extended time. However, this process is stressful and in the wild they almost always retain their juvenile, aquatic form.
How are axolotls able to regenerate lost limbs and organs?
-Axolotls form a blastema at the injury site made up of dedifferentiated cells that act like stem cells to regenerate the missing tissue. The signals that control this process are still being uncovered but appear similar to ones humans use during early embryonic development.
Do humans have any limb regeneration abilities?
-Humans can regenerate the very tips of digits, likely due to nail stem cells. Researchers also found mice and humans use some of the same genetic pathways as salamanders during this process. This suggests we may have latent regeneration abilities.
Why are axolotls almost extinct in the wild?
-The remaining habitat, Lake Xochimilco, is heavily polluted and invaded by non-native fish. The wild population has crashed to just a few hundred remaining individuals, though axolotls thrive in captivity around the world.
Could captive axolotls be reintroduced to the wild?
-Currently Lake Xochimilco is too degraded to support reintroduced axolotls. Scientists are exploring new protected habitats to build semi-wild populations with genetic diversity, though these would be outside their native range.
Why are axolotls important for medical research?
-Axolotls' ability to regenerate complex organs and tissues offers clues into unlocking latent healing abilities in humans. Axolotls also played a key historical role in discovering hormones that regulate metamorphosis.
How does axolotl limb regeneration work?
-After losing a limb, axolotls form a regeneration bud or blastema made of dedifferentiated cells at the injury site. These cells act like embryonic stem cells, slowly reforming bone, skin, veins and nerves to regrow the missing limb.
Do axolotls have special regeneration genes?
-No, axolotls do not have special regeneration genes. They regulate their existing genes differently, being able to unlock latent embryonic programs for regrowing missing tissues and organs.
What ecosystems in Mexico have high biodiversity?
-Mexico's grasslands and rainforests have extremely high biodiversity comparable to the Amazon. Over 10% of Earth's species live in Mexico across many unique ecosystems, earning it megadiverse status.

Outlines

00:00

🦎 The Aztec myth of axolotls and the legend of the Five Suns

The Aztec legend of the Five Suns explains the creation of the current world era in which humans were created. Axolotls feature in this myth as the god Xolotl, who transformed into different forms to avoid being sacrificed before being spared and banished by his brother Quetzalcoatl.

05:03

🌿 Axolotls retain juvenile traits as an adaptation to their lake habitat

Axolotls and some other salamanders in the Mexican lakes retain juvenile traits into adulthood, a phenomenon called neoteny. This is an adaptation as the lakes provide a stable aquatic habitat without fish predators, surrounded by dry land unsuitable for metamorphosed adults.

10:10

⚗️ Axolotls' incredible regenerative abilities make them key research animals

Axolotls can regenerate almost any body part, including limbs, organs, parts of the brain and spinal cord. They do this by transforming cells back into stem cells. Understanding this ability could benefit human medicine, making axolotls critical research animals.

15:11

😢 The axolotl is nearly extinct in the wild due to Mexico City's growth

The axolotl's lake habitat has shrunk to 2% of its former size and become highly polluted as Mexico City expanded. Captive axolotls are inbred and lack genetic diversity. Conservation efforts focus on relocating axolotls to new habitats.

20:12

🌐 Mexico is a megadiverse country, with axolotls one of many threatened species

Mexico is among the most biodiverse countries globally but many endemic species like the axolotl face extinction threats. A bundle offer for CuriosityStream and Nebula provides a way to learn more while supporting educational content creation.

Mindmap

Keywords

💡axolotl

The axolotl is the main subject of the video. It is a unique species of salamander found only in the Lake Xochimilco area near Mexico City. The axolotl is known for its ability to regenerate limbs, organs, and even parts of its brain. This ability makes it an important model organism in medical research. However, axolotls are close to extinction in the wild due to habitat loss and pollution.

💡regeneration

Regeneration refers to the axolotl's extraordinary capacity to regrow limbs, organs, and other body parts after injury. The video explores the biological mechanisms behind this ability, which involves stem cells and genetic regulation. Understanding axolotl regeneration could have major medical applications for humans.

💡neoteny

Neoteny means that axolotls retain juvenile, larval characteristics like gills and fins into adulthood instead of undergoing metamorphosis. This is an adaptation to the historically fish-free lakes where they evolved.

💡thyroid

Thyroid hormones regulate metamorphosis in amphibians. The video describes how early 20th century experiments showed that feeding axolotls thyroid tissue from livestock triggered them to transform out of their neotenic state.

💡Lake Xochimilco

Lake Xochimilco, near Mexico City, is the only remaining natural habitat for wild axolotls. But pollution, invasive species, and habitat loss have decimated the population there, putting axolotls on the brink of extinction in the wild.

💡chinampas

Chinampas were artificial agricultural islands built by the Aztecs in the lake system around what is now Mexico City. This environment supported a large axolotl population in Aztec times.

💡blastema

The blastema is a structure that forms at the site of a lost axolotl limb, made up of dedifferentiated cells. It leads to the eventual regeneration of the missing limb.

💡macrophages

Macrophages are cells involved in the immune response to injury. Experiments have shown they also play a key role in axolotl limb regeneration.

💡biodiversity

The video notes that Mexico is one of the most biodiverse countries, home to 10% of species worldwide. Preserving fragile ecosystems like Lake Xochimilco is important to protect this biodiversity.

💡conservation

Though axolotls thrive in captivity, captive populations suffer from inbreeding depression. Conservation efforts to restore axolotls in semi-wild sanctuaries, along with habitat restoration, offer hope for saving this species.

Highlights

The legend of the Five Suns is the creation myth of our world

The god Xolotl transformed into forms like the maize plant and agave plant to evade being sacrificed

Axolotls are a type of salamander that live permanently in the water and retain juvenile characteristics their whole life

Axolotls can regenerate almost any part of the body including limbs, tails, organs, parts of the eye, and even brain parts

Axolotls played a key role in understanding thyroid hormones and marked the beginning of their contribution to medical research

Axolotls form a blastema structure from stem cells to regenerate limbs, unlike other vertebrates

Axolotls regulate their genes differently to unlock regeneration abilities, giving hope we could unlock this ability in humans

Wild axolotl populations have declined exponentially in recent decades and face annihilation

Captive axolotl populations lack genetic diversity and have issues with inbreeding and disease

Lake Xochimilco, the axolotl's only remaining habitat, is highly polluted and unsuitable for reintroduction

A proposed solution is establishing semi-wild axolotl populations in new habitats like abandoned quarries

Mexico is considered a megadiverse country, with over 10% of the world's species

Grasslands contain immense biodiversity comparable to tropical rainforests

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Transcripts

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