Big apple

On August 14, 2003, my wife and I were returning from a trip to Hawaii.  It was a lovely vacation, but the return home was, to put it mildly, fraught with mishaps.  The most spectacular one occurred as we were descending into LaGuardia Airport in New York City.  It was late afternoon and I was watching the lights of the city zooming along below us, when, all of a sudden...

... the entire skyline went dark.

I nudged Carol and asked her to confirm that I was, in fact, seeing what I thought I was seeing.  The pilot landed the plane, but the jet bridges weren't working so we deplaned via a rolling ladder.  The entire airport was dark except for a few lights that were kept on by a generator.  Remember that this is a little less than two years after 9/11, so our immediate (and terrifying) thought was that it was a terrorist attack, but it turned out we'd gotten caught up in the Great Northeastern Blackout, which knocked out the electricity to a huge chunk of the northeastern United States and eastern Canada, and which apparently had been triggered by a software bug.

The upshot was we got stuck in the airport overnight with a bunch of other people who were also trying to get back to the Ithaca area, and one of these was a very nice woman who worked for the Apple Genomics Project at Cornell Orchards.  That evening she and I had a real Nerd-O-Rama about the ins and outs of plant genetics, which was a very peculiar way to make the best of a bad situation.

She and her team had a fascinating job -- going all over Europe, the Caucasus, Anatolia, and Central Asia looking for apple germ line -- basically, anything that can be used to reproduce an entire tree (seeds and cuttings being two of the most obvious examples).  They hired translators to accompany them, who asked locals to point out the best apple trees for various uses -- cooking, cider, making wine or vinegar, drying/preserving, or eating fresh -- and they took samples of germ line (along with copious notes) to bring home to the Orchards for growing and hybridizing.  Besides just looking for good fruit quality, they were also interested in finding strains that are resistant to pests and diseases.

The most diversity they discovered was in Kazakhstan and Uzbekistan, which is where apples originate.  ("American as apple pie" is about as inaccurate as you can get; apples not only aren't native to the United States, they were brought into North America in the mid-1600s by a Frenchman, Pierre Martin -- who settled in Nova Scotia.)  And some research out of the Max Planck Institute for the Science of Human History that appeared last week in Frontiers in Plant Science found that the spread of apples from their homeland, thousands of miles across Europe, was due to two factors; megafauna and the Silk Road.

[Image licensed under the Creative Commons Sandstein, Civni-Rubens apple, CC BY 3.0]

The modern apple is the result of hybridization between at least four wild species, followed by centuries of backcrossing and artificial selection.  Let apples cross-pollinate and plant the seeds, and you'll end up with something like a wild crabapple.  Originally, the bright fruits of apples were eaten by large herbivores like horses and wild cattle, and the seeds dispersed long distances, but with the disappearance of the huge herds that used to exist in central Asia, apple seeds were poorly dispersed.  (Apples aren't the only plants that got into trouble when their seed-disperser disappeared, something about which I wrote in more detail a couple of years ago.)  Fortunately for apples, though, their many uses were noted by humans, and when people moved -- especially along the Silk Road -- they took apple germ line with them, just as my Cornell researcher friend did a thousand years later.

The author, Robert Nicholas Spengler, writes:

Large fruits in Rosaceae [the family apples belong to] evolved as a seed-dispersal adaptation recruiting megafaunal mammals of the late Miocene.  Genetic studies illustrate that the increase in fruit size and changes in morphology during evolution in the wild resulted from hybridization events and were selected for by large seed dispersers.  Humans over the past three millennia have fixed larger-fruiting hybrids through grafting and cloning.  Ultimately, the process of evolution under human cultivation parallels the natural evolution of larger fruits in the clade as an adaptive strategy, which resulted in mutualism with large mammalian seed dispersers (disperser recruitment).

Current archaeobotanical evidence seems to suggest that apple domestication took place over a period of less than 100 generations, much less for the earliest morphological changes.  It seems feasible that rapid domestication through hybridization occurred in as little as one or a few generations, and most of the modern diversity in landraces is probably a recent phenomenon, through directed breeding.  Not only do protracted models of domestication fall short when discussing apples, the concept of a “center” of domestication is misleading. Genetic studies illustrate that wild apple populations across Europe and West Asia collectively contributed to the modern domesticated apple in a hybrid complex of species distributed across a continent and a half.

So that's something to think about next time you bite into a crisp apple -- you're enjoying a fruit that has roots reaching back millions of years, the current shape, color, and taste of which were created by megafaunal seed dispersers and the travel of human populations down the Silk Road.

Oh, and we eventually did get back home.  Carol and I, our geneticist friend, and four other people finally decided to hire a limousine when it became obvious that (1) the power, and therefore the airport, was going to be out of commission for a long time, and (2) there wasn't a rental car to be had anywhere in the New York City area.  We figured that splitting the cost of a limousine all the way to Ithaca seven ways wasn't going to be much more than each of us separately hiring a rental car anyhow.  All was going well until the limousine overheated and died in the middle of nowhere in the Poconos, leaving us stranded by the side of the highway with all our luggage.

By then, even my new friend and I didn't feel much like talking about genetics.

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An apple a day

Some years ago I was chatting with a geneticist friend of mine about apples.

At that point she worked for Cornell University's Apple Genomics Project, which had as its goal studying the diversity of apple varieties out there, not only for the sake of preserving biodiversity, but also for its utility in breeding better varieties.  Toward that end, they funded a project to go to the homeland of the apple tree -- the Caucasus, Turkey, southern Russia, northern Iran, then eastward into Turkmenistan, Uzbekistan, and Kazakhstan -- and collect germ line.  In biology-speak, germ line is anything that can be used to reproduce a species.  In plants, this would be seeds (obviously), and for species that have the ability to be reproduced vegetatively, stem or root cuttings, bulbs, tubers, and so on.  In animals, fertilized eggs, or eggs and semen.  These then can be preserved (as with the astonishing Svalbard Seed Vault, hosted by Norway, now containing over twenty million seeds, including over one-third of the world's most important crop varieties), or else used to generate new individuals for crossbreeding or genetic extraction.

In the case of the apples, it was a project that was fascinating, not to mention intense.  The team went all over the apple homeland, bringing along a translator so they could speak to the people they ran into, and in each village they asked the same questions: do you have any apple trees?  If so, what do you use them for -- eating fresh, baking, cider, fermenting into an alcoholic beverage?

They returned home with hundreds of cuttings of apple trees no one in the United States had seen before.  Each had its own special qualities, whether it be taste, usefulness, or (in some cases) disease or insect resistance.  These were then sprouted or else grafted onto sapling apple trees of other varieties, and the flowers they produced cross-pollinated to other varieties to generate a new variety which -- with luck -- would have the best of the characteristics of both parents.

It was this technique that was used to develop what is clearly the best-tasting apple variety out there, the Honeycrisp.  (I know, in matters of taste, who can say what is better or worse?  The answer is: I can.  Honeycrisps are amazing, and I'm not accepting any commentary to the contrary.)  The Honeycrisp was developed at the University of Minnesota, and from genetic studies was found to be a cross between the variety "Keepsake" and an unnamed variety, MN1627, which was itself a cross between the heirloom apple variety "Duchess of Oldenburg" and the more familiar Golden Delicious.

So apple growers are always on the lookout for the Next Big Thing, and are always eager to find more varieties that might have characteristics lacking in the ones currently available.  This is why a recent study by the Washington State-based Lost Apple Project generated a lot of stir with the announcement that they had rediscovered ten different heirloom apple varieties in the United States that were thought to be extinct.

[Image courtesy of the U.S. Department of Agriculture Pomological Watercolor Collection / Rare and Special Collections, National Agricultural Library]

Using old nursery sales records, information about county fairs, property records, and newspaper clippings, volunteers identified abandoned orchards in Idaho and Washington, then spoke to current landowners for both information and permission.  Once the latter was granted, the team took germ line and fruit samples from every variety they could find, and were astonished to find that ten of them represented varieties growers hadn't seen for years.  "It was just one heck of a season," said Lost Apple Project volunteer E. J. Brandt.  "It was almost unbelievable.  If we had found one apple or two apples a year in the past, we thought we were doing good.  But we were getting one after another after another... I don’t know how we’re going to keep up with that."

So now we have living samples of the Gold Ridge and Butter Sweet apples, the Sary Sinap (native to Turkey), and the Streaked Pippin, which was recorded in New York as early as 1744, among others.

Me, I'm just curious as to what they all taste like.  The diversity of apple varieties is astonishing, and we're still discovering new ones (or, in this case, rediscovering old ones).  And that's despite the fact that apples aren't even native to North America, despite what "American as apple pie" would have you believe.  It makes me wonder what else is out there, not just in apples but in other fruits, flowers, trees, domestic animals...

Truly, what we have around us is exactly what Darwin's evocative words described -- "endless forms most beautiful and most wonderful."

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Finding a person who is both an expert in an arcane field like quantum physics, and is also able to write lucidly about it for the interested layperson, is rare indeed.  Such a person is Sean Carroll, whose books From Eternity to Here, The Particle at the End of the Universe, and The Big Picture explore such ideas as the Big Bang, the Higgs boson, and what exactly time is -- and why it seems to flow in only one direction.

In his latest book, Something Deeply Hidden, Carroll looks not only at the non-intuitive world of quantum physics, but at the problem at the heart of it -- the "collapse of the wave function," how a reality that is a field of probabilities (experimental data agrees with quantum theory to an astonishing degree on this point) somehow converts to a reality with definitive outcomes when it's observed.  None of the solutions thus proposed, Carroll claims, are really satisfying -- so physicists are left with a dilemma, a theory that has been experimentally verified to a fare-thee-well but still has a giant gaping unexplained hole at its center.

Something Deeply Hidden is an amazing read, and will fascinate you from page 1 until you close the back cover.  It will also repeatedly blow your mind in its description of a universe that doesn't behave at all like what common sense says it should.  And Sean Carroll is exactly the author to navigate these shark-infested waters.  This is a book you don't want to miss.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]