Speaker 1: Welcome to brain Stuff from how stuff works. Hey, brain Stuff,
Speaker 1: I'm Lauren vocal Bomb, And if you wander the protocyle
Speaker 1: at your local grocery store, you'll find a dazzling variety
Speaker 1: of tomatoes, from cherry or grape shaped to massive beefsteaks
Speaker 1: and gnarly heirlooms. The same with squash, potatoes, cucumbers, and
Speaker 1: leafy greens. This bounty of diverse colors, shapes, and sizes
Speaker 1: isn't the result of natural selection, but rather human selection.
Speaker 1: Over millennia, farmers and plant breeders have spotted useful mutations
Speaker 1: and fruits and vegetables. Taste your fruit better, yields novel shapes,
Speaker 1: and preserved those traits through conventional breeding techniques. The process
Speaker 1: is slow, but if you cross different strains enough times,
Speaker 1: eventually you may create something new enough and marketable enough
Speaker 1: to be called its own variety. That slow and steady
Speaker 1: conventional breeding process is about to get a big boost
Speaker 1: from advances in genetic mapping. With a tomato or cucumber
Speaker 1: genome in hand, plant breeders don't have to wait months
Speaker 1: for a tomato plant to bear fruit to know whether
Speaker 1: the tomatoes will be pear shaped. Or round. Instead, they
Speaker 1: can look for tell tell markers and a seedling's DNA,
Speaker 1: the code for specific fruit shape, size, and color. This
Speaker 1: technique of marker assisted selection promises to cut years off
Speaker 1: the traditional plant breeding process. One Esther vander Nap is
Speaker 1: at the forefront of genetic research into exactly how it
Speaker 1: plant's DNA instructs its fruit to grow long and lean
Speaker 1: like a hothouse cucumber, or round and squat like a
Speaker 1: beefsteak tomato. In her lab at the University of Georgia,
Speaker 1: post docs and undergraduates sliced tomatoes in half and place
Speaker 1: them on a flatbed scanner to measure the precise shapes
Speaker 1: and sizes produced by different genetic combinations. In a paper
Speaker 1: published in November of twenty eighteen in the journal Nature Communications,
Speaker 1: vander Nap announced the discovery of two families of genes
Speaker 1: that appear to play key roles in making fruits and
Speaker 1: vegetables either round or long. Fruits and vegetables are technically
Speaker 1: a plant's edible organs, and those organs grow and develop
Speaker 1: up through cell division. She explained, to make a certain shape,
Speaker 1: like a longer round shape, you need to have certain
Speaker 1: patterns of cell division, either the cells divide horizontally or
Speaker 1: they divide vertically, which makes sense. The more in organ
Speaker 1: cells divide horizontally by splitting down the middle, the more
Speaker 1: they're going to build up tissue horizontally, creating a fatter,
Speaker 1: rounder fruit. What vander Nap and her colleagues discovered in
Speaker 1: the tomato genome is a specific gene called ovate that
Speaker 1: appears to be responsible for creating proteins that tell cells
Speaker 1: to divide in a vertical pattern. When more cells split
Speaker 1: side to side, the growth pattern produces an elongated fruit.
Speaker 1: Ovate is the difference between a perfectly round cherry tomato
Speaker 1: and an oblong plum tomato. Wild tomatoes, like the native
Speaker 1: varieties found in Peru, Ecuador, and Mexico, are invariably small
Speaker 1: and round, says vander Nap, which means pear shaped and
Speaker 1: other elongated tomatoes are mutations that came along later as
Speaker 1: far back as the ninety Plant biologists called the elongation
Speaker 1: mutation ovate, but had no clue about the actual genetic
Speaker 1: mechanism behind it. But vander Nap and her team identified
Speaker 1: the ovate protein as well as another family of proteins
Speaker 1: called trms that interact with ovate, and it provides another
Speaker 1: tool to plant breeders who are using marker assisted selection.
Speaker 1: If the ovate n tr M markers are present, you
Speaker 1: can be sure the fruit will be elongated. If one
Speaker 1: or the other is missing, it's backed round. Vander Napp
Speaker 1: says this will speed up the breeding process and let
Speaker 1: growers focus on trickier traits like yield and pest resistance
Speaker 1: that aren't as easily linked back to one or two
Speaker 1: specific genes. So now the question is do these advances
Speaker 1: in plant genetics mean that your produce I will soon
Speaker 1: include square tomatoes or pyramid shaped pumpkins. Not likely, says
Speaker 1: vander Nap, but not because it's technically impossible. She says.
Speaker 1: There are tons of bizarre mutations in the tomato genome
Speaker 1: that result in odd looking fruits, and since those mutations
Speaker 1: are naturally occurring, they could be isolated and replicated in
Speaker 1: the lab. But the problem with square tomatoes and other
Speaker 1: oddball shaped fruit is twofold, vander Nap says, First, there's
Speaker 1: the GMO problem. If plant breeders use gene editing to
Speaker 1: directly tweak or replace genes in food plants, those trains
Speaker 1: are considered GMO, and some people get freaked out by
Speaker 1: the GMO label, even though genetically modified organisms as a
Speaker 1: category are no less or more safe than conventionally modified organisms. Second,
Speaker 1: exciting new fruit and vegetable shapes may not shape up
Speaker 1: in other ways. Vander Nap said, some mutations are so
Speaker 1: bizarre that no grower would grow them because they have
Speaker 1: lots of other problems. They only have a few fruit
Speaker 1: per plant, or they taste terrible because when you grow
Speaker 1: a fruit in a really odd shape, you mess up
Speaker 1: the hormone balance. It may not be very juicy or
Speaker 1: tasty at all. If you really want to grow a
Speaker 1: square tomato, says vander Nap, just put a box around it,
Speaker 1: like you may have seen downe with other fruit like watermelons.
Speaker 1: Should those hit the scene at a premium price, you
Speaker 1: can always try growing your own at home. There are
Speaker 1: plenty of instructions online for building your own square fruit boxes.
Speaker 1: Today's episode was written by Dave Ruse and produced by
Speaker 1: Tyler Clang for i Heeart Media and How Stuff Works.
Speaker 1: For more on this and lots of other well rounded topics,
Speaker 1: visit our home planet, how stuff Works dot com