Animals and plants share a common genetic ancestry, so perhaps vegetarians who refuse to eat meat on ethical grounds should avoid anything that has DNA at all. Is this feasible? Could anybody suggest a menu?
I鈥檓 not aware of any living organisms that don鈥檛 have DNA, so eating any tissues or cell cultures is pretty much ruled out. You could try eating RNA viruses, but you鈥檇 need to produce them in a cell culture, which generally requires animal serum to keep the cells alive. Your food wouldn鈥檛 contain DNA, but you would have used dead animals to produce it.
One cheat that springs to mind is . In many species, including humans, the nucleus and mitochondria are removed from these cells during the maturation process. This is to make room for more haemoglobin, the iron-bound protein that carries oxygen. Because the nucleus and mitochondria contain all the cell鈥檚 DNA, you could argue that provided you don鈥檛 kill the animals, drinking their blood is the ultimate vegetarian diet. You鈥檇 need to filter out the white blood cells, which still have plenty of DNA, but the rest of the blood components would be fine. They鈥檇 provide you with protein, some sugars and vitamins, but probably more iron than is healthy.
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If that doesn鈥檛 sound appealing, consider totally (bio)synthetic foods. Biologists routinely construct yeast and bacterial lines designed to churn out large quantities of a specific protein or other biological molecules. I assume it would be possible to scale this production up to produce sufficient quantities of purified proteins, sugars and so on to act as a food source. Don鈥檛 expect it to be tasty, though: the proteins and sugars produced would be purified from the culture as crystalline powders. I鈥檓 not sure whether it鈥檚 possible to produce fats like this without killing the cells, but if you did it would either be oil or a pretty nasty goo. Also, maintaining the cultures required to produce this stuff would rely on antibiotics to kill contaminant organisms, so going against the spirit of the idea.
Many, perhaps all, of the various vitamins and other nutrients we need could probably be synthesised in similar ways, given time and cash. The various mineral compounds we need 鈥� iron, copper, zinc, iodine and so on 鈥� are probably available from a good synthetic chemist. And, of course, you could drink milk. It鈥檚 a complex mixture of secreted proteins, fats, sugars and pretty much everything else you need to stay alive. It may contain cells from the animal which produced it, but you could probably centrifuge these out.
Christopher Binny, By email, no address supplied
All I can come up with is a dish of baked retrovirus served on a water biscuit made from purified starch, fried in a purified fat of choice and seasoned with salt and vinegar. For the sweet course you might try a sorbet of snow sweetened with a purified sugar, honey or syrup, a touch of citric acid for bite, and with added vitamins, trace elements and essential oils to taste. It should be washed down with any spirit, or any wine or beer filtered to remove yeast traces.
鈥淵ou could try baked retrovirus served on a water biscuit made from purified starch鈥�
Bryn Glover, Cracoe, North Yorkshire, UK
I found the following information on the wall of the Johnson Space Center in Houston, Texas. One cubic metre of lunar soil contains enough of the right elements to make a cheeseburger, an order of fries and a fizzy drink. That would contain no DNA, but might be a little expensive.
Graham Kerr, Glasgow, UK
I considered this some years ago and put my conclusions in the form of a cookery book, available online at .
Norman Paterson, Anstruther, Fife, UK
To whet your appetite, here鈥檚 a recipe from Paterson鈥檚 book 鈥� Ed
For four malachite burgers you will need:
Four slices of Welsh slate
1 kilogram of
Cut the slates in two. Break up the malachite with a sledgehammer. Divide the malachite equally among four slates and cover with the remaining four. Bake at 1200 掳C for 12 hours, by which time the malachite should be a beautiful bubbly green. Cool and eat. Excellent for picnics, as they can be prepared the century before. A dry gritty flavour.
Most people who are vegetarian on ethical grounds oppose killing of animals. They are rejecting the senseless deaths of the animals and the inhumane way the animals are treated, rather than worrying about similar DNA. Vegetarians have nothing against eating vegetable matter and fungi because these have no central nervous system and thus cannot experience pain.
Ceridwen Fitzpatrick, Perth, Western Australia
If all plants and animals have common DNA ancestry then perhaps we are all vegetarians. We are all also vegetables and for that reason the world is awash with cannibalism.
Indeed, vegetarians can eat their neighbours. By the 鈥渃ommon DNA鈥� logic this is no more or less cannibalistic than eating a radish. The only solution to this dilemma would be for every creature to subsist purely on non-living minerals and nutrients. Animals, however, are unlikely to stop eating what they want.
Brian Falconer, Aberdeen, UK