Reviving the Moa

Recently Labour MP Trevor Mallard, in a breakfast meeting with Wainuiomata business owners, suggested moa might roam the hills again in 50 or 100 years. He was widely mocked by politicians and pundits, but could he be onto something? How difficult would it be to resurrect the moa?
Ever since Jurassic Park brought back dinosaurs the idea of de-extinction has gripped our imagination, but the science has yet to live up to the hype. Geneticists have cloned a few animals and moved DNA around in the lab, but no species has returned from the dead yet. To revive an extinct animal, we need at least three things: all of its DNA, some way of getting that DNA into a living egg, and a mother for the egg that could incubate it or bring it to term.

In the early days on moa DNA research, chunks of bone were drilled out of museum specimens, ground up, and the DNA extracted. This revolutionised our understanding of the moa family tree, but the only a tiny percentage of the genome was recovered, and it was heavily contaminated with the DNA of microbes and even people who’d handled the bones.

In the early days on moa DNA research, chunks of bone were drilled out of museum specimens, ground up, and the DNA extracted. This revolutionised our understanding of the moa family tree, but the only a tiny percentage of the genome was recovered, and it was heavily contaminated with the DNA of microbes and even people who’d handled the bones.

The first step might be the easiest with moa. The DNA we’ve recovered from moa bones and eggs is in tiny fragments, most of it is missing, and it’s contaminated by microbes, but technological advances over the last 20 years have made us better at figuring out where the fragments might fit together. We haven’t figured out the entire moa genome yet, though we’re getting closer; it’s been successfully done for Neanderthals and mammoths. This is all on computers but we don’t know how to assemble the actual fragments like a giant jigsaw yet. Even if we did, building chromosomes out of the DNA would be very tricky. Nevertheless, these problems are ones we may well solve.

 

Recently researchers have discovered that moa DNA is preserved much better on eggshell than in bones; the pores of eggs protect it from the elements and contamination by bacteria. DNA from the inside of the shell is of both male and female chicks, but from the outside is only from males.

Recently researchers have discovered that moa DNA is preserved much better on eggshell than in bones; the pores of eggs protect it from the elements and contamination by bacteria. DNA from the inside of the shell is of both male and female chicks, but from the outside is only from males.

The second step is harder. A mammal’s egg can be extracted, its DNA replaced, and the egg coaxed into dividing again until it’s stable enough to implant back into the womb; this is how cloning works. The problem with bird eggs is they have a hard shell, and puncturing this, taking out an embryo, and reintroducing it after it’s been dividing for many generations is in the Too Hard basket at the moment. We can’t even clone chickens yet with a multi-billion-dollar poultry industry backing researchers. Extinct mammals, therefore, are likely to be revived well before we get around to birds.

 

 

Uncovered in 1931 during gravel excavation near Tokomaru, this egg of Anomalopteryx didiformis, the Little Bush Moa, is one of the six most-complete moa eggs in the world. Because it’s almost the same size as an ostrich’s, it represents the largest moa species we would be able to hatch from the egg of a living bird.

This egg of Anomalopteryx didiformis, the Little Bush Moa, is almost the same size as an ostrich’s egg and represents the largest moa species we would be able to hatch from the egg of a living bird.

A final problem with resurrecting moa is which egg would we use? Giant moa had eggs 24 cm long, much bigger than even an ostrich (the largest egg available), so there’s no living species that could hatch a giant moa chick. Some of the small moa species had ostrich-sized eggs (there is one in the Whanganui Regional Museum) but there’s a second problem: ostriches are only distant relatives of moa, no more closely related than horses are to cows. Transplanting the DNA of one into the embryo of the other is an insurmountable problem, at least at the moment.
So reviving moa would be very difficult, but there are other candidates that seem much more likely. Mammoths, for example, will almost certainly be resurrected before moa are. Mammoth cells have been snap-frozen in relatively good condition, so scientists have been able to sequence their genome. They have close living relatives; woolly mammoths are actually more closely related to Indian elephants than African elephants are. And the technology for cloning mammals is far more advanced than for birds. So in theory it’s certainly possible that one day an elephant will give birth to a mammoth calf.

 
But when? It might be 50 years before mammoth cloning is a reality, and moa would take even longer. By then, what state will the Siberian tundra be in? Will the mammoths have to live out their lives in zoos? There are big ethical questions about bringing back an animal with no habitat, at great expense, when other species are dying out for want of conservation dollars.
New Zealand forests, by contrast, evolved to deal with moa browsing. We could even see moa as an essential part of our forest ecology, missing for centuries, replaced by destructive mammals like deer and pigs. Luckily, we’ve spent decades perfecting ways to wipe out introduced pests and restore damaged forests; in 50 years, if we put our minds to it, we could have prime moa habitat ready to go when the technology catches up. Perhaps our grandchildren will get to see moa in the bush again.
 
Dr Mike Dickison is the Curator of Natural History at Whanganui Regional Museum and did his PhD research on the evolution of giant flightless birds.

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