Butterflies, wasps and interspecies gene transfer

The more we look, the more we find that transgenic behavior—moving genetic material between unrelated life forms, is common in nature.

One of the hallmarks of the anti-GMO movement seems to be the argument that it’s unnatural to move, for example, bacterial DNA into plants to make them resistant to certain bug predators.

It not only isn’t unnatural, but it happens all the time in nature.

“Breaching the species barrier,” it’s called. It turns out this barrier is pretty porous.

We’ve reported earlier about naturally transgenic sweet potatoes. 

And we’ve reported on virus DNA movement into human DNA and bacteria DNA into animals. 

New evidence released just last week shows that parasitic wasps have inserted viral DNA into butterfly genomes. The viral DNA turns off portions of the butterfly immune system. 

All of this interspecies trade allows the wasps to insert their eggs into the butterfly caterpillar phase without their being attacked by the butterfly immune systems. Creepy, but that's nature.

Here is the Sept. 17, 2015,paper reporting on that finding. It's in the latest PLOS Genetics and is problematically entitled "Recurrent Domestication by Lepidoptera of Genes from Their Parasites Mediated by Bracoviruses."

The process of moving genetic material between species is called horizontal gene transfer. 

The new paper concludes that while science has assumed that species have needed to reshuffle their own genes to fight off  new threats, in fact,  horizontal gene transfer is “recognized as an important factor in…evolution.”

“We show here that in several lineages, lepidopteran genomes have acquired genes from a bracovirus that is symbiotically used by parasitic wasps to inhibit caterpillar host immune defences,” the paper says.

The research suggests that the wasps initially collected the viral DNA, carried it within their bodies, and then transferred it to the butterflies. They used the viral DNA as a kind of tool kit to allow them to carry out their own life cycles.

And there’s more. It appears that the butterflies have then been able to use the borrowed genes to fight off a virus that can attack them.

“Additionally, we present functional analyses suggesting that some of the acquired genes confer to caterpillars a protection toward baculovirus, a very common pathogen in the field. This phenomenon may have implications for understanding how caterpillars acquire resistance against baculoviruses used in biological control,” the paper says.

 

Evolutionary biologist Louise Johnson, at the British University of Reading, said it’s a fine example of just how adaptive evolution can be.

"This three-way gene shuffle is a particularly clear and clever example: wasps use viruses to attack butterflies, but those viruses have also allowed the butterflies to steal genes from the wasps. 

“It’s clear that the stolen genes are useful to the butterflies, so naturally occurring genetic engineering helps them to survive. 

“From my perspective as an evolutionary biologist, it’s also a perfect illustration of how evolution uses every trick in the book, and the book is bigger than we think,” Johnson said.

© Jan TenBruggencate 2015

Sea level rise has been artificially low in Hawai`i—but it’s going to catch up

Sea levels are rising globally at an increasing rate—three inches in the last 25 years or so--but we’re not seeing that much in Hawai`i.

So what’s up?

One answer to this mystery is that our islands are in a kind of temporary sweet spot. Satellite imagery shows that while most of the globe has seen dramatic rises in sea levels—as much as 3 inches in the past 25 years—Hawai`i has been flat to actually lower.

(Image: The red shows areas of dramatic sea level rise. Blue shows areas where it’s flat or down. Hawai`i appears in the blue zone. But how long will that last? Credit: NASA.)

At a human scale, this makes no sense. If you fill a bathtub, clearly it fills all around the tub.

But global scales are different. There are humps and valleys in the oceans across the scale of thousands of miles. Winds can push water up against a coast, creating a hump. Eddies can change sea levels regionally. Currents and storms and tides and even temperatures can all impact the height of the ocean.

“In a nutshell it's due to changes in winds and ocean circulation that counteract the global sea level signal regionally. That should shift as part of a long-term fluctuation but no projections on when that is likely to occur. This big El Nino may herald the start of a shift, but we have to see how that plays out,” said University of Hawai`i oceanographer Mark Merrifield.

Here is NASA’s recent report on accelerating sea levels and related issues. 

“Sea levels are rising rapidly—much more rapidly than they have any time in the last several thousand years,” said NASA’s Joshua Willis, at the Jet Propulsion Laboratory. 

And the rate of increase has been increasing as well, he said. It was about 1 millimeter annually in 1900, rose to 2 millimeters annually in the mid 1900s, and is now at 3 millimeters annually. That works out to more than an inch a decade.

I wrote to Willis to ask whether our islands can continue to dodge this bullet.

“In the long run sea level rise will affect Hawaii as well. Because it is in the central Pacific, the impacts of the long-term natural cycles may not be quite as large. Eventually, however, the global rates of rise will be felt in Hawaii also,” he said.

University of Hawai`i coastal geologist Charles “Chip” Fletcher agreed.

“The global oceans cannot keep rising without us experiencing the rise as well - we just may be able to avoid the worst aspects of the variability. On the other hand, models show that the tropics as a region will experience the upper end of global sea level change, so that makes us part of a more dangerous region.

“I have held for several years that Hawaii should plan for one meter of sea level rise by end of century and as far as I can see that is still a valid number,” he said.

© Jan TenBruggencate 2015

Hawai'i's depleted natural treasure chest: oh, what we've lost

There were many jewels in Hawai`i’s natural treasure chest, and today, the rarest of these are the land snails.

The Hawaiian archipelago's natural legacy was a splendid array—forest birds in all the colors of the rainbow, flashing reef fishes found nowhere else on the planet, and the stunning silver and crimson, gold and purple hues of the flowers.

In that array, the land snails may not stand out, although there were once hundreds of species. Today, they are recognized for their singular rarity.

(Image: One of the last remaining amastrid land snail species on O'ahu, Laminella sanguinea, in the Waianae Mountains. Credit: Kenneth A. Hayes, University of Hawai’i)

There were once 325 species of Amastridae that were unique to these islands. Today, only 15 can be found.. An extinction rate of more than 95 percent.

This tally was published in the journal "Conservation Biology" by researchers from the University of Hawai`i’s  Pacific Biosciences Research Center, Bishop Museum, and national and international teams. It is entitled “Extinction in a hyperdiverse endemic Hawaiian land snail family and implications for the underestimation of invertebrate extinction."

Of the 325, only 33 are officially listed as extinct on the International Union for Conservation of Nature (IUCN) Red List. But that’s because the paperwork can’t keep up with the rate of extinction.

“Of the 325 Amastridae species, 43 were originally described as fossil or subfossil and were assumed to be extinct. Of the remaining 282, we evaluated 88 as extinct and 15 as extant and determined that 179 species had insufficient evidence of extinction (though most are probably extinct),” the authors wrote.

When scientists write about extinction crises, they’re often mostly talking about vertebrates—the birds and mammals, fishes and reptiles. But  to miss the invertebrates is to miss a lot. 

“Invertebrates have received much less attention despite their constituting as much as 99% of animal species richness,” the authors write.

To assess the status of Amastridae, the researchers studied collections in the Bishop Museum and then went into the field, looking t 481 potential snail habitats throughout the Islands.

“At many sites, we collected leaf litter and soil, which we searched under a microscope for especially small snails. This is the most comprehensive and temporally focused land snail survey effort ever undertaken in the Islands,” they wrote.

They found just the 15. If you’re interested in the list, here it is.

“These 15  species  were  recorded  during  recent field work, including our field work specifically targeting amastrids in the Waianae Mountains of Oahu (Amastra cylindrica , Amastra micans , Amastra spirizona , Laminella sanguinea , Leptachatina cerealis , Leptachatina crystallina , Leptachatina gracilis , Leptachatina gummea , Leptachatina persubtilis, Leptachatina popouwelensis ), on Kauai (Leptachatina cuneata , Leptachatina cylindrata), on Maui (Laminella aspera , Leptachatina nitida), and on the island of Hawaii ( Leptachatina lepida),"

What could have caused this extinction catastrophe? Not just one cause. The authors make a list.

Humans (early Hawaiians) arrived and launched habitat destruction. They also brought Polynesian rats, which ate some snails but weren’t as big an issue as later introductions. 

Then came Europeans with the next big wave of extinctions, caused by pigs, goats, and other species. Polynesian rats and black rats arrived and were big predators of snails. 

Massive land clearing for ranching and plantation agriculture added to the toll, along with introduced predatory snails, and ants, and competition from introduced non-predatory snails.

Some of the same authors also participated in another paper that looked at extinction of poorly known life forms globally. Again, it suggests the extinction rate in modern times is far higher than we’ve believed. 

 

Among its points: “Mammals and birds provide the most robust data, because the status of almost all has been assessed. Invertebrates constitute over 99% of species diversity, but the status of only a tiny fraction has been assessed, thereby dramatically underestimating overall levels of extinction. Using data on terrestrial invertebrates, this study estimates that we may already have lost 7% of the species on Earth and that the biodiversity crisis is real.”

© Jan TenBruggencate 2015

Weird eats, weird thoughts, and how to live nearly forever

When it comes to food, we’re touchy. 

We’re prone to believe all kinds of strange stuff--some things that just aren’t true at all, and a lot of things that are only marginally true, and a fair amount of things that are just weird.

We’re likely to be convinced that certain foods are literal life-savers. 

That, for example, you’ll be eternally protected if you eat enough blueberries, or noni, or whole grain bread, or tree nuts, or seaweeds, or salba seed, or honey, or bee pollen, or coconut oil, or cruciferous vegetables, or chia seeds, or salmon, or chicken rather than beef, or fish rather than pork—this list goes on forever. 

Just Google ‘miracle foods.’

And we believe bad things about certain foods. 

The tomato, today a key ingredient in salads and Italian cooking, 200 years ago in the United States was believed poisonous. Today, it is sometimes listed among the miracle foods. How things change.

The tomato is an American plant that was happily and safely eaten by Central Americans. But for strange reasons, some of them religious, it was deemed toxic in North America a couple of hundred years ago. It wasn’t until the tomato had been exported to Europe, turned into a key part of that cuisine, and brought back to America by immigrants, that tomatoes were trusted again.

  

Folks used to believe eggplants would cause insanity.

And a lot of people today believe that meat is bad for you, despite this intriguing statistic:  almost all of the longest-lived peoples in the world eat meat. The key: They seem to eat it infrequently and then sparingly.

Folks in Sardinia, Italy, where they eat a lot of milk and cheese, live on average a very long time—they are among the longest living group of people in the world. You’ve been told those dairy products are bad for you, right? 

Oh, and you’ve been told alcohol is bad for you. Sardinians drink wine, too.

Noted Hawai`i physician nutritionist Dr. Terry Shintani recommends eating unprocessed foods. His diet suggestions include a lot of fresh stuff, mostly vegetarian, and a lot of it local. That is one interesting feature of the diets of almost all of the longest-living people—they eat stuff that comes from their immediate environment.

They eat the milk and meat of animals they knew, vegetables from gardens they tended or their friends did.

Some folks will argue that you’re likely to get much better nutrition and be much healthier if you eat an organic diet. Is there any actual support for that position? Not according to a paper in the Annals of Internal Medicine. 

“The published literature lacks strong evidence that organic foods are significantly more nutritious than conventional foods,” the study says. 

So what is reasonable advice? Some seems to come from the U.S. Department of Health and Human Services’ Dietary Guidelines for Americans 2010. It says stay active, eat fewer calories and be mindful of what you’re eating.

“A healthy eating pattern limits intake of sodium, solid fats, added sugars, and refined grains and emphasizes nutrient-dense foods and beverages—vegetables, fruits, whole grains, fat-free or low-fat milk and milk products, seafood, lean meats and poultry, eggs, beans and peas, and nuts and seeds,” it says.

Not as interesting, perhaps, as blueberries and chia seeds on kale leaves, but there you go.

Looking at another standard, there seem to be three hallmarks of virtually every one of the most long-living communities in the world: They are active lifelong, and they don’t eat a lot, and they eat local produce.

Some of them drink alcohol, some not. Almost all eat meat and dairy products, although almost all eat meat only sparingly. A lot eat a lot of fresh fruit, nuts and vegetables. 

That suggests this recipe for a long, healthy life. Finish your salad, push the main course away after only a bite or two, and then get up take a long walk.

© Jan TenBruggencate 2015

The colors of life--in space

On Earth, researchers use fine differences in light and color to identify specific plant species in aerial photos, and even to distinguish diseased or stressed plants from healthy ones.

What if we could use a similar technique to identify life on other planets?

A team of University of Hawai`i scientists is proposing just that, and is targeting our nearest solar neighbor, Alpha Centauri—a binary star that is the third brightest star in the night sky. Its alternative names are Rigil Kent and Toliman.

The team is led by Dr. Svetlana Berdyugina, a visiting scientist at the University of  Hawai`i’s NASA Astrobiology Institute, working with Hawai`i astronomers Jeff Kuhn, David Harrington and John Messersmith.

They propose to use existing telescopes that are outfitted with special polarization equipment, and to compare the light from space with the colors from Earth-based photosynthetic pigments. Reflected polarized light from a planet can be picked up even when a nearby star is overwhelmingly brighter.

In their research, the team “found that each biopigment has its own colored footprint in such polarized light,” they said in a pressrelease.

They seem to admit that chances seem slim. A single planet was discovered last year around one of Alpha Centauri’s three stars, Alpha Centauri B. But this planet is far closer to its sun than even baked Mercury is to our sun, and so hot that water probably can’t exist at the surface. 

But using the powerful polarized photosynthetic signatures might identify other planets in what astronomers call the habitable zone—that area where liquid water can exist on the surface. The team believes that within the star cluster, Alpha Centauri B holds the best chance of having  planets in the habitable zone.

© Jan TenBruggencate 2015