Tag Archives: kiwi

The Kiwifruit duplicated its vitamin C genes twice — 20 and 50 million years ago

Kiwis employed a genetic trick, researchers say.

Fruits of different kiwi species.

Although kiwifruits are widely associated with New Zealand, they’re actually native to China, where more than half of the global kiwi supply is produced. A member of the gooseberry family, a kiwi contains about as much vitamin C as an orange, thanks in part to a genetic trick called polyploidy. Basically, the kiwifruit’s ancestors spontaneously duplicated their DNA — twice.

“Polyploidy is an abrupt evolutionary event that produces thousands of extra copies of genes overnight,” says senior author Xiyin Wang, an agricultural plant scientist at the North China University of Science and Technology. “These extra copies may greatly elevate the robustness of the plant, providing opportunities for natural selection to prune and rewire its biological system over time.”

They found these traces by comparing the kiwi genome to other related and better-studied plants: coffee and grapes. Kiwis, coffee, and grapes share a common ancestor and thus share large swaths of genetic information.

When they compared these genomes, they found that the kiwi genome had four or five copies of a gene in places where the coffee and grape genomes had only one. This particular gene was responsible for creating and recycling vitamin C.

Vitamin C isn’t only good for humans — it also contributes to plant growth and resilience, so the kiwi produced it to gain an evolutionary advantage. Meanwhile, the coffee plant didn’t need to utilize this method as its main asset was the production of caffeine — which is a natural pesticide that can also kill neighboring plant competition. Grapes, on the other hand, developed a dark pigment to give them an edge during cold spells.

Moreover, researchers say this was likely the result of an auto-polyploidization event, meaning that the kiwi duplicated its own genes (in other words, this was not a result of inter-breeding). It’s not clear how common this strategy is among other plants and plant groups.

Aside from offering some intriguing insight into the evolutionary history of the kiwi, this could also allow researchers to artificially mimic the technique, copying certain genes to grow more nutritious or disease-resistant produce.

“Our research has decoded the structure and evolution of the kiwifruit genome,” says Wang. “Kiwifruit is one important fruit, rich in vitamin C. Understanding its genomic structure may help us manipulate its genes to produce more nutritious kiwifruit.”

Wang and his team are currently looking at analyzing the genome of other agricultural plants to see whether other genes could be copied to produce more successful fruits and vegetables.

Journal Reference: iScience, Wang et al.: “Two likely auto-tetraploidization events shaped kiwifruit genome and contributed to establishment of the Actinidiaceae family.” https://www.cell.com/iscience/fulltext/S2589-0042(18)30115-9

The amazing Tuatara

The tuatara is not an iguana, it’s not a lizard, and it is very, very different than any other reptile alive today on Earth. In fact, recent studies suggest that it’s pretty different from any other vertebrate. It’s home is in New Zealand, which is known for eccentric life forms of all kinds: the kiwi, with long whiskers and feathers just like fur, the kakapo, the parrot that can’t fly and looks like an owl, and the giant weta, a cricket as big as your fist. However, as amazing and special as these animals are, they fade in comparison to the tuatara.

About 80 million years ago, the supercontinent Gondwana split up, leaving life on this paradise island evolutionary separated from the rest of the world. The tuatara is about 16 inches long, and it’s practically a living fossil – it hasn’t changed significantly in hundreds of millions of years. It has a third eye, the legendary but unexplained pineal eye, located on the forehead and used for registering light intensity and regulating body temperature.

But what is extremely weird is that a few regions of the tuatara DNA are evolving at an incredible speed, probably with the fastest mutation rate ever in vertebrates. The rapidly changing DNA sequences are limited to so-called neutral regions of the tuatara’s DNA, and affect rather fillings and not the basic “blueprint” of the tuatara. They are also very different from reptiles too.

“Their biology is quite distinctive,” said Charles Daugherty of the Allan Wilson Center for Molecular Ecology and Evolution at Victoria University of Wellington in New Zealand. “They have a unique type of hemoglobin, and their enzymes are set to function at lower temperatures than in most reptiles.” As a result, tuataras remain active at night, and in weather just a few degrees above freezing, said Dr. Daugherty, “at temperatures at which most reptiles couldn’t survive.”

But the tuatara gets even more awesome. They routinely live to 100 years, and often go above 150 or even 200; they also live it up – females can reproduce up until 80-100 years. They’re also mean and like to show off, and even fight when necessary

“They have crests they can inflate, to make them look big, and they stand very tall and start mouth-gaping at each other,” said Dr. Godfrey. “If one male doesn’t get the message, it will escalate into a physical fight.” They tear at each other’s crests and toes, they trade parasites. “During mating season, you can see the bright orange patches of mites on their necks,” said Dr. Godfrey. “It’s quite spectacular.”

Today, there are less than 50.000 tuataras, all of which are considered to be a national treasure.

Try Adding These Superfoods

There’s a common misconception that the foods that are good for you are just spinach and broccoli, or something else which just taste really bad; numerous people would want to eat healthy foods but they find that these foods are just not tasty. For them there is a new generation of superfoods that promise to do double or triple-duty in what concerns health. Here are some foods you can add to your Thanksgiving Dinner.

At the top of the list—kiwi: tasty, Vitamin-C filled kiwi.

“In a recent study, kiwi was found to be one of the most nutritionally dense fruits out of 27 fruits,” says Stephanie Dean, R.D., dietitian with Baylor University Medical Center at Dallas. They are full of antioxidants, vitamin E and lutein which are very important. Then you have barley which is a grain and could be added to soups or even eaten instead of oatmeal for breakfast.

After that you can eat something which is a Thanksgiving favorite for numerous people; they are named cranberries. Not the band.

“The crimson color of cranberries signal that they are full of flavonoids,” explains Dean. Flavonoids contain very high levels of antioxidants and they prevent everything from infections to strokes and cancer.

After that something which is going to help your calcium is kefir.

“Kefir is a wonderful source of calcium. Every eight ounce glass has about 300 milligrams which is a little less than one-third of the recommended daily intake for adults,” says Dean.

What makes it so good is the fact that it has much calcium as milk and more beneficial bacteria than yogurt. And then a close relative of an old superfood would go just great. Broccoli sprouts are sold by the package and can be thrown on top of salads or can be a great addition to sandwiches. They taste a bit better.

“Broccoli sprouts have been shown to actually contain 20 percent more anti-cancer agents than regular broccoli,” says Dean.

So here is how you can have a very tasty and healthy Thanksgiving Dinner with very little effort. These foods are found in grocery stores.