Book summary “Bring back the king”: summary

Introduction

You live in a world haunted by creatures you will never see alive. Extinction once felt final, leaving you with only fossils and museum displays to imagine the lost giants of the past.

Modern science is changing that finality through de-extinction. Helen Pilcher explores how genetic engineering moves resurrection from science fiction into reality, allowing you to witness the return of lost species.

This book guides you through the complex landscape of bringing extinct animals back to life. You will discover what science can actually achieve and where nature draws hard limits.

• Can you truly clone a dinosaur from fossilized remains?
• Where do researchers draw the ethical line with human relatives?
• How do scientists use gene-editing tools to recreate mammoths?
• What challenges face the resurrection of birds, marsupials, and amphibians?

1. Extinction and the Limits of Ancient DNA

An asteroid the size of Mount Everest struck Earth approximately 65 million years ago with the force of six billion Hiroshima bombs. This impact created a dark, cold global winter that starved plant-eating dinosaurs and subsequently their predators over hundreds of thousands of years.

Stan, a 20-year-old Tyrannosaurus rex specimen discovered in South Dakota, represents the apex predators that vanished during this mass extinction event.

Dinosaurs and Fossils

Despite its terrifying reputation, an adult Tyrannosaurus rex could not actually run and possessed specific biomechanical limitations. Biomechanics calculations show that an adult T. rex could not achieve true running because it would need over 80 percent of its total mass in its hind leg muscles to become airborne. Instead, it power-walked using muscly buttocks and puny ankles, reaching top speeds of around 40kph.

John Hutchinson from the Royal Veterinary College calculated T. rex movement dynamics, while Heinrich Mallison generated computer models showing stride mechanics and turning inertia.

When you face the unlikely threat of a prehistoric encounter, you can use specific evasion tactics:

• Run for the hills when being chased by a T. rex because bigger animals find uphill movement harder.
• Run up hills in a zigzag pattern to exploit the dinosaur's slow turning inertia.
• Head for somewhere with big obstacles like a thickly wooded forest.
• Try tripping the dinosaur up so the 6-tonne mass hitting the floor with a deceleration of 6 g would shatter its ribs and internal organs.

Certain organic molecules like melanin can survive the fossilization process essentially undamaged over millions of years. Mary Anning discovered fossilized squid ink in 1828 that could be turned into a sepia-like ink and used for drawing. Modern analysis confirms this ink consists of melanin, an extremely recalcitrant organic pigment that chemically matches modern cuttlefish ink.

Mary Anning found a smooth, rounded grey stone on the beach at Charmouth in Dorset, split it open with her hammer, and used the preserved Jurassic squid ink to illustrate her fossil finds.

Mary Schweitzer discovered that soft tissues, cell-like structures, and proteins can sometimes survive inside dinosaur fossils. By dissolving the mineral component of dinosaur bone fragments in weak acid, Schweitzer repeatedly retrieved springy, fibrous organic material, transparent blood vessel tubes, red blood cells containing haem, and osteocyte outlines.

Mary Schweitzer analyzed a T. rex named Wankel Rex and a well-preserved T. rex named Bob from the Badlands of Montana.

The Limits of DNA

DNA is a fragile molecule with a measurable half-life, making the recovery of dinosaur DNA practically impossible.

Biochemist Tomas Lindahl established that DNA breaks down over time and has a half-life of 521 years. After approximately 6.8 million years, every single link between DNA letters in a genome is completely destroyed, ruling out the recovery of intact dinosaur DNA.

Russell Higuchi and Allan Wilson first retrieved DNA from a 140-year-old quagga in 1984, while the current record for ancient DNA belongs to a 700,000-year-old horse frozen in Canadian permafrost.

Jack Horner proposes creating a dinosaur by reversing evolution through the genetic manipulation of modern bird embryos. Because birds are direct descendants of theropod dinosaurs, Horner aims to reactivate dormant ancestral genetic instructions in chicken embryos to make them grow dinosaur-like features such as snouts, teeth, forelimbs, and tails.

Arkhat Abzhanov used gel beads laced with proteins to alter gene expression in chicken embryos to grow a dinosaur-like snout instead of a beak. Malcolm Logan introduced the Pitx1 gene to grow leg-like forelimbs, and Matthew Harris altered beta-catenin levels to grow alligator-like teeth.

2. Neanderthal Science and Ethics

Advanced genome editing makes cloning an extinct human relative theoretically feasible, but doing so crosses an ethical boundary that should never be breached.

Neanderthal DNA and Social Life

Archaeologist Ralph Solecki and his team exhumed the bodies of seven adults and two children in the Zagros Mountains of northern Iraq, uncovering evidence of prehistoric compassion. Analysis of the skeletal remains of Shanidar #1, or Nandy, an adult male Neanderthal from the Shanidar Cave in Iraq, revealed severe trauma including a bashed-in skull, a withered and amputated right arm, a broken foot, and chronic arthritis. Despite being blind, paralysed down one side, and in constant pain, his bones showed signs of healing and he survived to around age 40, proving he was fed, protected, and supported by his community.

Svante Pääbo overcame the assumption that ancient DNA completely degrades by reasoning that enzymes needing water to break down DNA cannot function in desiccated or mummified tissues. Pääbo bought a cow's liver from a local supermarket, baked it on a low heat in a laboratory oven to create a mummified hunk of meat, and successfully retrieved its undamaged DNA fragments.

Hendrik Poinar collected wall-to-wall dung balls from the dry floor of the Rampart Cave in the Grand Canyon, Arizona. Poinar studied ancient faeces from the extinct Shasta ground sloth and discovered that heat over millennia causes the Maillard reaction, where sugars form cross-links with proteins and DNA.

The Ethics of Human Cloning

George Church and other geneticists note that because modern humans and Neanderthals share over 99 percent of their DNA, scientists could take a human genome inside a human cell and use advanced editing techniques to make the roughly 10 million required changes to create a Neanderthal-like sequence. This modified DNA could then be placed into an enucleated human egg and implanted into a surrogate mother. The New York Times reported that a Neanderthal could theoretically be brought back to life with existing technology for around $30 million.

To achieve this resurrection, geneticists must follow specific laboratory steps:

• Break up the human genome into smaller chunks and ferry them into specially adapted bacteria.
• Make the desired Neanderthal-like changes using Multiplex Automated Genome Engineering (MAGE).
• Reassemble the modified DNA into 23 pairs of chromosomes inside human cells.
• Inject the Neanderthal DNA into a human egg with its nuclear genome removed.
• Transfer the developing embryo into the womb of a human surrogate to carry to term.

Thomas Wynn explored how a Neanderthal child would fit into a modern household, noting a strong preference for immediate family security and home schooling over large nursery groups. Based on fossil and genetic data, a cloned Neanderthal boy named Hermann would likely be delivered by C-section due to a brain 10 percent larger than ours, might be pale-skinned with red hair due to high-latitude genetic adaptations, and would thrive in a loving nuclear family.

Bioethicist Arthur Caplan notes that no specific laws prohibit human species cloning because ancient DNA was off the radar when international treaties were drafted. Francis Collins argued that implanting the product of human cloning into a uterus is profoundly immoral and should be opposed on the strongest ethical grounds.

The author ordered a $99 DNA testing kit from 23andMe, spat into a high-tech tube, and discovered her genome contains 3 percent Neanderthal DNA, putting her in the 91st percentile. Svante Pääbo and Joshua Akey discovered that people of European and Asian descent carry between 1 and 4 percent Neanderthal DNA in their genomes, whereas people from Africa carry none because their ancestors never met Neanderthals.

3. Mammoths and the Permafrost

As the climate warms, the frozen north thaws, exposing well-preserved mammoth remains. Tusk collectors risk their lives in freezing waters and unstable ice caves to find tusks that can sell for tens of thousands of dollars, creating a local trade known as mammontit. Winter temperatures on Malyi Lyakhovski island plunge to 30 below in Celsius.

In August 2012, tusk collectors on Malyi Lyakhovski island discovered a frozen mammoth complete with flesh, skin, fur, and a tousled brown trunk.

Geneticists use CRISPR technology to introduce cold-adaptation traits into elephant genomes, aiming to recreate mammoth-like proxies to restore ancient ecosystems.

Sergey Zimov's Pleistocene Park project attempts to recreate the ancient mammoth steppe ecosystem to prevent the release of sequestered carbon from thawing permafrost. Large herbivores trample snow and expose soil to cold air, keeping the ground frozen and preventing the carbon time bomb in the permafrost from releasing greenhouse gases. Zimov populates his reserve with imported herbivores like Yakutian horses and reindeer to restore the grassland.

Zimov used helicopters to introduce stocky Yakutian horses to a reserve in the Sakha Republic, successfully turning a moss-filled wilderness into a lush grassland within one season.

Estimates suggest that 500 gigatonnes of organic carbon are sequestered inside the Arctic's frozen soil. Sergey Zimov has spent 20 years trying to recreate the mammoth's original ecosystem. Computer models predict that ice-free Arctic summers could arrive by 2052.

The Permafrost Gold Rush

Early attempts to clone the woolly mammoth from frozen calves failed due to poor tissue preservation, tissue damage during transport, and the limitations of 1980s cloning technology. Cell biologist Viktor Mikhelson attempted to take a nucleus from a preserved mammoth calf named Dima and inject it into an enucleated elephant egg, but the tissue had rotted and been ruined by taxidermy chemicals.

Viktor Mikhelson tried for months in the 1980s to clone the mammoth calf Dima, but the specimen was too degraded to yield viable cells.

Kazufumi Goto proposed creating a mammoth-elephant hybrid by fertilising an elephant egg with frozen mammoth sperm, then backcrossing successive generations. Recognising that dead bull sperm could produce test-tube cattle via IVF, Goto planned to use recovered mammoth sperm to create a half-mammoth, half-elephant hybrid and breed it back until a genetically pure mammoth emerged.

Goto and Akira Iritani traveled to Siberia in 1997 to find mammoth tissue, but the recovered sample turned out to be a rancid piece of a woolly rhino. Fifty per cent of finds were ruled out because the animal would need to be male.

The birth of Dolly the sheep on 5 July 1996 revolutionized cloning science by proving that adult cell nuclei can be reprogrammed into an embryonic state. Before Dolly, mammals had never been cloned using DNA from an adult cell. Her birth demonstrated that old DNA could be tricked into becoming young again, inspiring researchers like Akira Iritani to restart mammoth cloning efforts.

Dolly was cloned using a cell from the mammary gland of an adult female sheep at Scotland's Roslin Institute and named after Dolly Parton.

Gene Editing and Surrogacy

Modern research teams established dedicated laboratories in Siberia and partnered with South Korean cloners to study exceptionally preserved mammoth specimens in situ. Woo Suk Hwang's Sooam Biotech Research Foundation partnered with the North-Eastern Federal University to perform a forensic autopsy on the Malyi Lyakhovski mammoth and look for viable cells suitable for cloning.

In March 2014, scientists performed a CSI-style autopsy on the Malyi Lyakhovski mammoth, discovering that its muscle looked like fresh supermarket beef and finding traces of haem in its liquid blood.

In 2012, Sooam entered an agreement with NEFU. Woo Suk Hwang has cloned approximately 500 dogs. If you ever examine such a specimen, you must follow strict preservation rules:

• Wrap the entire body with wet bathing towels.
• Place it in the fridge (not the freezer) to keep it cool.

George Church uses CRISPR gene-editing technology to alter elephant genomes directly, introducing cold-adaptation traits to create a mammoth-like animal. Rather than relying on finding intact mammoth cells with viable nuclei, Church compares the mammoth and Asian elephant genomes to identify key differences. Using CRISPR-Cas9, he edits elephant cells to incorporate traits like cold-resistant haemoglobin and thick fur.

Church and his colleagues have used CRISPR to edit genes for mammoth haemoglobin into the nucleus of an elephant cell.

The comparison revealed 1.4 million DNA letters that were different between the mammoth and Asian elephant genomes, with 1,600 protein-coding genes altered by these genetic differences. CRISPR was propelled into the spotlight in 2012 by Doudna and Charpentier, and high-quality versions of the mammoth genome were published in 2015.

Attempting to de-extinct the mammoth through elephant surrogacy poses severe logistical hurdles and ethical concerns regarding the welfare of endangered Asian elephants. Harvesting elephant eggs, creating embryos in vitro, and performing embryo transfers require navigating the complex reproductive anatomy of elephants. Critics argue that using endangered Asian elephants as surrogate mothers subjects them to high-risk, unproven procedures.

Thomas Hildebrandt's veterinary team has refined techniques to harvest elephant eggs, but no one has ever successfully created an elephant embryo in the lab or carried out a successful elephant embryo transfer.

Female elephants have a pregnancy period lasting 22 months and release a single egg every four months. Some mammoth species roamed 300 miles per year, and modern elephants eat 200kg of food per day. Pleistocene Park covers an area of 160 square kilometres.

Even if mammoths could be successfully resurrected, they would arrive too late and in insufficient numbers to prevent the Arctic permafrost from melting. Climate experts note that generating a single viable herd would take well over half a century, by which time current predictions suggest Arctic summer ice will already be gone and the carbon time bomb will have exploded.

Climate engineer Hugh Hunt points out that the North Pole needs to be refreezed in the next 10 to 20 years, making mammoths ineffective as climate change superheroes.

4. Feathered Resurrections

Bypassing the complex reproductive tracts of birds requires innovative cell biology techniques like injecting primordial germ cells into surrogate host embryos.

Dodos and Passenger Pigeons

Having evolved on Mauritius without natural predators, dodos lost their ability to fly and became remarkably trusting. When 17th-century sailors arrived, the birds approached them out of curiosity and were easily killed, leading to unfair caricatures of them as sluggish and dim-witted. Dutch seafarers called them dodaersen or fat-arses, and Carl Linnaeus later named the bird Didus ineptus. The dodo species became completely extinct around 1693.

The Oxford dodo consists of a desiccated head and foot. Ancient DNA researchers Alan Cooper and Beth Shapiro extracted short snippets of mitochondrial DNA from its bone, confirming the dodo is a pigeon whose closest living relative is the Nicobar pigeon. However, warm and acidic conditions destroy nuclear DNA, making full resurrection of the dodo genetically unfeasible.

In the early nineteenth century, passenger pigeons numbered in the billions, darkening the skies in enormous flocks. Humans massacred them for cheap meat using guns, nets, alcohol-soaked corn, and fire, while European settlers simultaneously felled half of North America's native woodland, driving the species into total collapse. Martha, the last passenger pigeon on Earth, died on September 14, 1914, at the Cincinnati Zoological Gardens.

Led by organizations like Revive and Restore, and driven by scientist Ben Novak and geneticist Beth Shapiro, researchers are sequencing fragmented DNA from museum specimens and using the band-tailed pigeon as a genetic template to recreate passenger pigeon traits. Ben Novak raised $4,000 from family and friends to start sequencing passenger pigeon DNA on his own before joining Revive and Restore.

Avian Reproductive Technology

Because bird reproduction involves automated assembly lines adding whites and shells around fragile yolks, traditional cloning is extremely difficult. Instead, cell biologists like Il-Kuk Chang and Michael Kjelland inject primordial germ cells from one species into the bloodstream of a host embryo so they migrate to the gonads and produce foreign sperm or eggs. Cell biologist Il-Kuk Chang injected chicken primordial germ cells into a duck embryo, producing a drake that generated chicken sperm and fathered pure chicken chicks.

If you want to work with avian reproductive technology, you must follow specific laboratory steps:

• Collect avian eggs as soon as they have been ovulated, before the white and shell have been added.
• Use a steady hand and a tablespoon to scoop out grape-sized yolks.
• Use a technique combining microscopy and chemical stain to visualize the egg's DNA.
• Puncture the structure and use a fine glass pipette to remove the egg's own DNA.
• Add donor DNA into the empty egg and coax the cell to start dividing.
• Transplant the embryo back into the reproductive tract of an adult bird or place it inside a hollowed regular egg shell for incubation.

Passenger pigeons relied on living in massive flocks for survival and infant care, abandoning their young early in development. Critics like Mark Avery argue that releasing a small captive-bred group is unviable, while releasing millions of them would recreate a species that historically devastated crops, broke tree branches under their weight, and acted as feathered locusts. A witness in 1855 described passenger pigeon flocks causing children to scream, horses to bolt, and forests to look as if they had been swept by a tornado.

5. Marsupials and Amphibians

Nuclear transfer experiments and unique reproductive biology offer pathways to resurrecting lost marsupials and gastric-brooding frogs.

The thylacine, or Tasmanian tiger, was driven to extinction through a combination of habitat loss, competition with dingoes, and government-backed culls fueled by unfounded rumours of livestock predation. Settlers in nineteenth-century Tasmania blamed thylacines for failing sheep farms due to bad weather and poor management, making the animal a scapegoat and leading to a government bounty that decimated their numbers until the last known specimen, Benjamin, died in captivity in 1936. Benjamin, the last known thylacine, died of exposure and neglect at the Beaumaris Zoo in Hobart on 7 September 1936, after his keepers forgot to open his nighttime enclosure. Since that day, researchers have recorded 4,000 reported sightings of possible thylacines. Thylacines first appeared 25 million years ago.

Preserved museum specimens preserved in alcohol retain extractable DNA, offering a potential genetic library for de-extinction attempts. Michael Archer found a thylacine pup in a glass jar at the Australian Museum in Sydney in 1976, inspiring the idea to use its preserved DNA for cloning. Paleontologist Michael Archer discovered a pickled thylacine pup in a museum jar and realized that alcohol preservation maintains cellular DNA, which geneticists later confirmed could be extracted to reconstruct a genome using the Tasmanian devil as a surrogate. In 1990, Archer conceived the idea of cloning the thylacine from museum specimens, and in 2008 Andrew Pask extracted a thylacine DNA fragment and successfully used it to switch on a collagen gene in mouse embryos.

The Lazarus Project

The southern gastric-brooding frog exhibited a unique reproductive strategy where the female swallowed fertilized eggs and brooded them in her stomach before giving birth through her mouth. An adult female southern gastric-brooding frog measured 7 cm, while a full-term froglet reached 1 cm, and a mother could fit a maximum of 20 froglets inside her stomach. The mother frog's stomach acted as a womb where tadpoles metamorphosed over six weeks while secreting hormones like prostaglandin E2 that temporarily halted the production of stomach acid, before the fully formed froglets were expelled via belching. Biologists David Liem, Chris Corpen, and Greg Roberts observed captured frogs in a living room tank when an adult regurgitated live froglets instead of digesting them.

The global decline and extinction of amphibian species, including the gastric-brooding frog, have been heavily driven by the spread of a deadly chytrid fungus. The chytrid fungus enters amphibians through their skin, disrupts their fluid balance, and causes fatal heart failure, serving as the most significant vertebrate disease in recorded history and wiping out the gastric-brooding frogs shortly after their discovery. Over 30 years, chytrid caused approximately 200 frog species to decline or go extinct. Michael Mahony discovered the northern gastric-brooding frog in Eungella National Park in 1984, only to watch local populations rapidly crash due to the disease.

Nuclear transfer experiments proved that mature, specialized cells retain the complete genetic information required to direct the development of an entire organism. In 1952, Briggs and King published their first nuclear transfer research, and in 2012 John Gurdon was awarded the Nobel Prize for Physiology or Medicine. John Gurdon transplanted nuclei from the intestinal epithelial cells of tadpoles into enucleated frog eggs, successfully producing cloned tadpoles and winning a Nobel Prize.

The Lazarus Project attempted to de-extinct the gastric-brooding frog by injecting dead frozen nuclei into the enucleated eggs of a living related species. Michael Archer's team retrieved tissue from frozen museum specimens and transferred the nuclei into de-jellied eggs of the Great Barred Frog, successfully producing early cell divisions and primitive backbones before development halted prior to gastrulation. Andrew French and the Lazarus team collected Great Barred Frog eggs at night, carefully removed their gelatinous layers, and observed initial cell divisions from frozen gastric-brooding frog DNA. The gastric-brooding frog tissue spent 30 years frozen in a chest freezer, and the experiments yielded 7 or 8 live Lazarus embryos created for every 100 nuclear transfer experiments.

You can follow these exact steps for the procedure:

• Collect female Great Barred Frogs during seasonal breeding nights in the summer months.
• Treat females with hormone extracts purified from cane toad pituitary glands to stimulate ovulation.
• Delicately massage the abdomen of females to harvest freshly laid eggs.
• Remove the multiple layers of protective jelly using chemicals, UV light, and fine forceps.
• Inject the dead donor nucleus into the enucleated live frog egg.

Conclusion

De-extinction forces you to weigh scientific triumph against profound ecological and ethical responsibility. Resurrected animals will serve as functional proxies rather than exact genetic replicas of lost species. You must navigate a future where biotechnology blurs the line between extinction and preservation.

1. Prioritize living habitats and endangered species before attempting the resurrection of lost ones.
2. Treat de-extinction candidates as ecological tools designed to restore damaged environments rather than mere museum exhibits.
3. Establish strict regulatory frameworks to govern genetic editing and surrogate implantation before releasing proxies into the wild.
4. Separate the pursuit of technological capability from ethical restraint when considering hominid resurrection.

10 Key Ideas

1. DNA breaks down over time with a measurable half-life, completely ruling out the recovery of intact dinosaur DNA after approximately 6.8 million years.
2. Advanced genome editing makes cloning an extinct human relative theoretically feasible, but doing so crosses an ethical boundary that should never be breached.
3. Geneticists use CRISPR technology to introduce cold-adaptation traits into elephant genomes, aiming to recreate mammoth-like proxies to restore ancient ecosystems.
4. Attempting to de-extinct the mammoth through elephant surrogacy poses severe logistical hurdles and ethical concerns regarding the welfare of endangered Asian elephants.
5. Bypassing the complex reproductive tracts of birds requires innovative cell biology techniques like injecting primordial germ cells into surrogate host embryos.
6. Passenger pigeons relied on living in massive flocks for survival and infant care, abandoning their young early in development.
7. Preserved museum specimens preserved in alcohol retain extractable DNA, offering a potential genetic library for de-extinction attempts.
8. Nuclear transfer experiments proved that mature, specialized cells retain the complete genetic information required to direct the development of an entire organism.
9. Resurrected animals will serve as functional proxies rather than exact genetic replicas of lost species.
10. De-extinction forces you to weigh scientific triumph against profound ecological and ethical responsibility.