Tag Archives: #tree

When It Comes To Genes, We’re All Much More Alike Than Different (Biology)

You’re 99.9 percent genetically identical to every human being you meet. George Clooney, Donald Trump, Serena Williams, your annoying coworker, the Pope — they’re all basically the same as you (genetically speaking).

Whether you’ve experienced culture shock in a foreign country or just sat down to dinner with your family and felt you couldn’t possibly be related to those weirdos, everyone has felt detached from other human beings at some point. At those moments, it’s good to remember the simple fact that we are all more alike than we are different.

Your genome is made up of 3 billion base pairs, the teeny-tiny chemical units that make up the genes that form the twisting, paired strands known as DNA. That means that between any two people, roughly 2.999 billion base pairs will be exactly the same. To put that another way, if you printed your genome, it would take up to 262,000 pages, and only 500 would differ from person to person.

Why is this? It’s because most of our genome does the same thing across the animal kingdom. Consider the differences between your house and the Notre Dame Cathedral. At first glance, they look very different, but they share a lot of similarities: both have foundations, doorways, windows, and a roof, to name just a few. The form these take differ, but their basic building blocks are the same. It’s similar with DNA. Most of the genetic building blocks are the same across species. The tiny differences between two organisms come down to a sliver of their genomes.

As a result, you’re 94 percent identical to your dog and 90 percent identical to your cat, genetically speaking. For cows, it’s 80 percent. You’re even strikingly similar to insects: the fruit fly, a popular subject of genomic research, shares 60 percent of your genes (including two-thirds of cancer genes!).

Humans are much more alike than they are different. In a world that seems to have more divisions every day, it’s important to remember our shared humanity. It’s right there in our genes.

Genomic Study Reveals Evolutionary Secrets Of Banyan Tree (Botany)

The banyan fig tree Ficus microcarpa is famous for its aerial roots, which sprout from branches and eventually reach the soil. The tree also has a unique relationship with a wasp that has coevolved with it and is the only insect that can pollinate it.

The banyan tree Ficus macrocarpa produces aerial roots that give it its distinctive look. A new study reveals the genomic changes that allow the tree to produce roots that spring from its branches. ©Photo by Gang Wang

In a new study, researchers identify regions in the banyan fig’s genome that promote the development of its unusual aerial roots and enhance its ability to signal its wasp pollinator.

The study, published in the journal Cell, also identifies a sex-determining region in a related fig tree, Ficus hispida. Unlike F. microcarpa, which produces aerial roots and bears male and female flowers on the same tree, F. hispida produces distinct male and female trees and no aerial roots.

Understanding the evolutionary history of Ficus species and their wasp pollinators is important because their ability to produce large fruits in a variety of habitats makes them a keystone species in most tropical forests, said Ray Ming, a plant biology professor at the University of Illinois, Urbana-Champaign who led the study with Jin Chen, of the Chinese Academy of Sciences. Figs are known to sustain at least 1,200 bird and mammal species. Fig trees were among the earliest domesticated crops and appear as sacred symbols in Hinduism, Buddhism and other spiritual traditions.

The relationship between figs and wasps also presents an intriguing scientific challenge. The body shapes and sizes of the wasps correspond exactly to those of the fig fruits, and each species of fig produces a unique perfume to attract its specific wasp pollinator.

To better understand these evolutionary developments, Ming and his colleagues analyzed the genomes of the two fig species, along with that of a wasp that pollinates the banyan tree.

“When we sequenced the trees’ genomes, we found more segmental duplications in the genome of the banyan tree than in F. hispida, the fig without the aerial roots,” Ming said. “Those duplicated regions account for about 27% of the genome.”

The duplications increased the number of genes involved in the synthesis and transport of auxins, a class of hormones that promote plant growth. The duplicated regions also contained genes involved in plant immunity, nutrition and the production of volatile organic compounds that signal pollinators.

“The levels of auxin in the aerial roots are five times higher than in the leaves of trees with or without aerial roots,” Ming said. The elevated auxin levels appear to have triggered aerial root production. The duplicated regions also include genes that code for a light receptor that accelerates auxin production.

When they studied the genome of the fig wasp and compared it with those of other related wasps, the researchers observed that the wasps were retaining and preserving genes for odorant receptors that detect the same smelly compounds the fig trees produce. These genomic signatures are a signal of coevolution between the fig trees and the wasps, the researchers report.

Ming and his colleagues also discovered a Y chromosome-specific gene that is expressed only in male plants of F. hispida and three other fig species that produce separate male and female plants, a condition known as dioecy.

“This gene had been duplicated twice in the dioecious genomes, giving the plants three copies of the gene. But Ficus species that have male and female flowers together on one plant have only one copy of this gene,” Ming said. “This strongly suggests that this gene is a dominant factor affecting sex determination.”

Provided by University Of Illinois

The “Lord Of The Forest” Is A Massive Tree Known To Bring Visitors To Tears (Amazing Places / Nature)

As you step out of the dense undergrowth, the brush and saplings around you seem to bow in awe towards the lordly presence in the center of the clearing. You look up … and up … and up as you take in the majesty of Tāne Mahuta, the Lord of the Forest.

Sometimes a presence is so overwhelming that you just can’t help but break down and cry. That’s not an uncommon sight at Tāne Mahuta, the largest kauri tree in the world. Even an average kauri specimen is truly massive — the trees regularly exceed 16 feet (5 meters) around and grow to heights in excess of 100 feet (30 meters). There’s a reason why any forest that has them is known as a kauri forest, regardless of whether they are the dominant species.

But the “Lord of the Forest,” named after a Māori forest god, puts all of his neighbors to shame. This kauri is a staggering 50 feet (16 meters) around and reaches a height of 148 feet (45 meters). That’s about as tall as a 14-story building. It takes a long time for a tree to reach that height, and Tāne Mahuta is estimated to be about 2,500 to 3,000 years old. That means it was a sapling when humans were first entering the Bronze Age.

Tāne Mahuta isn’t alone in the rainforest, however. While the Lord of the Forest is easily the largest kauri tree in the world, its nearby neighbor Te Matua Ngahere, the “Father of the Forest,” holds the record as the stoutest. It’s 55 feet (17 meters) around. Some estimates place this behemoth at 4,000 years old, older than the earliest known alphabets. It’s easy to see why these trees occupy such a central place in the cosmology of New Zealand.

Besides their stunning appearance above ground, kauri trees set themselves apart with a uniquely shallow root network. Unlike many very large trees, which nourish themselves on mineral deposits deep beneath the ground, kauris extend thin tendrils along the surface and feed off of decomposing organic matter. But given their size, they also need something to hold them down, so they also have deep peg roots that don’t gather any nutrients.

Unfortunately, that feeding system also leaves the giants vulnerable. In recent years, the trees have been suffering from a new disease known as kauri dieback. It’s caused by outside contaminants seeping into those shallow roots, sometimes by wandering mammals and sometimes on the soles of visiting hikers. That’s why, if you’re going to visit either Tāne Mahuta or Te Matua Ngahere, you need to hose your shoes off first.

Gaint Hogweed Is The Skin-Burning, DNA Attacking Plant Of Your Nightmares (Botany)

There’s something out there — something dangerous. It’s an invader, and it’s spreading faster than we humans can contain it. All it needs to do is touch you, and your skin will start to blister and peel. Even worse, it will attack the very building blocks of your DNA. But this isn’t John Carpenter’s “The Thing.” It’s just another deadly plant: the giant hogweed. Watch out!

Giant hogweed isn’t new in the United States, but it’s spreading. It has been here since 1917 when New Yorkers brought it over to the Big Apple to decorate their gardens. Sure, why not? What could go wrong? It’s not as if a pretty white flower can grow into a massive, flesh-mutating monstrosity, right? Right?

You already know where this is going, but let’s just run down the facts. Giant hogweed really puts the emphasis on “giant.” It looks a bit like Queen Anne’s Lace, but where that harmless plant is only 4 feet (1.2 meters) tall or so, giant hogweed can grow as high as 20 feet (6.1 meters). Of course, it’s not the size that makes the hogweed dangerous. It’s the sap. Brushing up against the plant can expose you to chemicals known as furocoumarins — they’re phototoxins, meaning they can be dangerous when exposed to light. If that happens, electrons from the toxins bind to the DNA bases thymine and cytosine, preventing them from enabling basic cellular function. Within 15 minutes, your skin can start to blister and peel as if from the worst sunburn of your life.

In Virginia, where giant hogweed plants were discovered for the first time this year, a teenage landscaper was recently severely injured after he cut down a plant not knowing what it was. His recovery may take quite some time. As Alex Childress told People, “I can’t go out into the sun for anywhere from two to six months. My face could be sensitive to light for a year up to two years.” Of course, his was a quite severe case — if all you’ve done is brush against a plant, just wash the affected area with soap and cold water, and try to avoid the sun for two days.

The United States isn’t the only place where giant hogweed has been spreading like, well, a weed. The plant originated in the Caucuses, but spread across continental Europe, the British Isles, across the ocean to the States, and across another ocean to Australia and New Zealand (generally by gardeners without a lot of foresight). But once it’s established itself in a place, it spreads with impunity. Its giant size makes it take up a lot of resources that could have been used by its gentler competitors, and every giant hogweed produces more than 100,000 seeds per year. But that all begs the question: Why is there such a panic over giant hogweed right now?

It’s not the first time the plant has stepped into the spotlight as a threat to public health. Writing for The Guardian, Jane Perrone notes that a similar panic occurred in 1970, even though the plant had been a fixture of the English countryside since the 19th century. So where were all the reports of blistered unfortunates from the decades previous? Experts have a few ideas.

It could be that 1970 and 2015 (the year the article was written) were both “vintage years” for giant hogweed in the UK, meaning it was particularly widespread so more people could encounter it not knowing the risks. That seems to match up with what’s going on in the USA right now since the plant certainly seems to be booming this year as it expands its territory. There’s also the simple fact that modern people may have less botanical knowledge in general. Maybe the kids of those 1917 gardeners knew the risks that giant hogweed posed ahead of time and simply didn’t take their chances. In any case, one thing is clear: If you encounter a towering white flower on your next nature hike, steer clear.

The World’s First Trees Don’t Have Rings (Botany / Paleontology)

Every child knows that you can tell the age of a tree by counting its rings. For scientists studying a 374-million-year-old tree, that posed a problem — and not because it’s really easy to lose track of your count when you pass 20 million or so. The trunk of this tree didn’t have any rings at all, and that completely changes our understanding of how trees evolved.

Fig: A foreman uncovers a fossilized tree trunk, thought to be more than 350 million years old, at a quarry in upstate New york in 1920s

In May 2017, a team of researchers from Cardiff University in Wales, Nanjing Institute of Geology and Palaeontology in China, and State University of New York announced that the trunk of an ancient tree belonging to the group called cladoxlopsids — the ancestor of modern trees and ferns — looks nothing like the trees of today.

Tree rings are composed of xylem, a tissue that transports water from a tree’s roots to its tips. In most trees, xylem grows in a single cylinder just under the bark. New wood grows on top of that, and the tree gets ever bigger in a predictable yearly cycle. (Interestingly, palm trees don’t have rings. Their xylem grows in strands, which is why a cross-section of a palm tree is covered in dots instead of rings.)

Fig: Cardiff University/ Dr. Chris Berry

But this ancient tree fossil looked nothing like that. Instead of growing xylem in yearly rings or in strands distributed throughout, this tree grew narrow strands in the outer five centimeters of its trunk, connected together in a web formation. That means that instead of rings, the cross-section of the fossil is covered in what is like Dalmatian spots. Each of those spots, or strands, grew its own xylem rings, creating what was essentially tree trunks growing within a tree trunk. As those interconnected mini-trees got bigger, their connections split apart and repaired themselves to keep the tree from breaking under its own weight. The result was a huge tree with a flat base and a bulbous trunk.

“There is no other tree that I know of in the history of the Earth that has ever done anything as complicated as this,” said Cardiff University researcher Chris Berry in a press release. “The tree simultaneously ripped its skeleton apart and collapsed under its own weight while staying alive and growing upwards and outwards to become the dominant plant of its day.”

What’s unusual for evolution is the fact that these trees aren’t any less complicated than modern ones. Why would the oldest trees use such a complex growth strategy? To answer this question, the researchers will need to find more fossils just as well-preserved as this one.