Tag Archives: Monarch butterfly

Of puke, CRISPR, fruit flies, and monarch butterflies

I’ve never seen an educational institution use a somewhat vulgar slang term such as ‘puke’ before. Especially not in a news release. You’ll find that elsewhere online ‘puke’ has been replaced, in the headline, with the more socially acceptable ‘vomit’.

Since I wanted to catch this historic moment amid concerns that the original version of the news release will disappear, I’m including the entire news release as i saw it on EurekAlert.com (from an October 2, 2019 University of California at Berkeley news release),

News Release 2-Oct-2019

CRISPRed fruit flies mimic monarch butterfly — and could make you puke
Scientists recreate in flies the mutations that let monarch butterfly eat toxic milkweed with impunity

University of California – Berkeley

The fruit flies in Noah Whiteman’s lab may be hazardous to your health.

Whiteman and his University of California, Berkeley, colleagues have turned perfectly palatable fruit flies — palatable, at least, to frogs and birds — into potentially poisonous prey that may cause anything that eats them to puke. In large enough quantities, the flies likely would make a human puke, too, much like the emetic effect of ipecac syrup.

That’s because the team genetically engineered the flies, using CRISPR-Cas9 gene editing, to be able to eat milkweed without dying and to sequester its toxins, just as America’s most beloved butterfly, the monarch, does to deter predators.

This is the first time anyone has recreated in a multicellular organism a set of evolutionary mutations leading to a totally new adaptation to the environment — in this case, a new diet and new way of deterring predators.

Like monarch caterpillars, the CRISPRed fruit fly maggots thrive on milkweed, which contains toxins that kill most other animals, humans included. The maggots store the toxins in their bodies and retain them through metamorphosis, after they turn into adult flies, which means the adult “monarch flies” could also make animals upchuck.

The team achieved this feat by making three CRISPR edits in a single gene: modifications identical to the genetic mutations that allow monarch butterflies to dine on milkweed and sequester its poison. These mutations in the monarch have allowed it to eat common poisonous plants other insects could not and are key to the butterfly’s thriving presence throughout North and Central America.

Flies with the triple genetic mutation proved to be 1,000 times less sensitive to milkweed toxin than the wild fruit fly, Drosophila melanogaster.

Whiteman and his colleagues will describe their experiment in the Oct. 2 [2019] issue of the journal Nature.

Monarch flies

The UC Berkeley researchers created these monarch flies to establish, beyond a shadow of a doubt, which genetic changes in the genome of monarch butterflies were necessary to allow them to eat milkweed with impunity. They found, surprisingly, that only three single-nucleotide substitutions in one gene are sufficient to give fruit flies the same toxin resistance as monarchs.

“All we did was change three sites, and we made these superflies,” said Whiteman, an associate professor of integrative biology. “But to me, the most amazing thing is that we were able to test evolutionary hypotheses in a way that has never been possible outside of cell lines. It would have been difficult to discover this without having the ability to create mutations with CRISPR.”

Whiteman’s team also showed that 20 other insect groups able to eat milkweed and related toxic plants – including moths, beetles, wasps, flies, aphids, a weevil and a true bug, most of which sport the color orange to warn away predators – independently evolved mutations in one, two or three of the same amino acid positions to overcome, to varying degrees, the toxic effects of these plant poisons.

In fact, his team reconstructed the one, two or three mutations that led to each of the four butterfly and moth lineages, each mutation conferring some resistance to the toxin. All three mutations were necessary to make the monarch butterfly the king of milkweed.
Resistance to milkweed toxin comes at a cost, however. Monarch flies are not as quick to recover from upsets, such as being shaken — a test known as “bang” sensitivity.

“This shows there is a cost to mutations, in terms of recovery of the nervous system and probably other things we don’t know about,” Whiteman said. “But the benefit of being able to escape a predator is so high … if it’s death or toxins, toxins will win, even if there is a cost.”

Plant vs. insect

Whiteman is interested in the evolutionary battle between plants and parasites and was intrigued by the evolutionary adaptations that allowed the monarch to beat the milkweed’s toxic defense. He also wanted to know whether other insects that are resistant — though all less resistant than the monarch — use similar tricks to disable the toxin.

“Since plants and animals first invaded land 400 million years ago, this coevolutionary arms race is thought to have given rise to a lot of the plant and animal diversity that we see, because most animals are insects, and most insects are herbivorous: they eat plants,” he said.

Milkweeds and a variety of other plants, including foxglove, the source of digitoxin and digoxin, contain related toxins — called cardiac glycosides — that can kill an elephant and any creature with a beating heart. Foxglove’s effect on the heart is the reason that an extract of the plant, in the genus Digitalis, has been used for centuries to treat heart conditions, and why digoxin and digitoxin are used today to treat congestive heart failure.

These plants’ bitterness alone is enough to deter most animals, but a small minority of insects, including the monarch (Danaus plexippus) and its relative, the queen butterfly (Danaus gilippus), have learned to love milkweed and use it to repel predators.

Whiteman noted that the monarch is a tropical lineage that invaded North America after the last ice age, in part enabled by the three mutations that allowed it to eat a poisonous plant other animals could not, giving it a survival edge and a natural defense against predators.

“The monarch resists the toxin the best of all the insects, and it has the biggest population size of any of them; it’s all over the world,” he said.

The new paper reveals that the mutations had to occur in the right sequence, or else the flies would never have survived the three separate mutational events.

Thwarting the sodium pump

The poisons in these plants, most of them a type of cardenolide, interfere with the sodium/potassium pump (Na+/K+-ATPase) that most of the body’s cells use to move sodium ions out and potassium ions in. The pump creates an ion imbalance that the cell uses to its favor. Nerve cells, for example, transmit signals along their elongated cell bodies, or axons, by opening sodium and potassium gates in a wave that moves down the axon, allowing ions to flow in and out to equilibrate the imbalance. After the wave passes, the sodium pump re-establishes the ionic imbalance.

Digitoxin, from foxglove, and ouabain, the main toxin in milkweed, block the pump and prevent the cell from establishing the sodium/potassium gradient. This throws the ion concentration in the cell out of whack, causing all sorts of problems. In animals with hearts, like birds and humans, heart cells begin to beat so strongly that the heart fails; the result is death by cardiac arrest.

Scientists have known for decades how these toxins interact with the sodium pump: they bind the part of the pump protein that sticks out through the cell membrane, clogging the channel. They’ve even identified two specific amino acid changes or mutations in the protein pump that monarchs and the other insects evolved to prevent the toxin from binding.

But Whiteman and his colleagues weren’t satisfied with this just so explanation: that insects coincidentally developed the same two identical mutations in the sodium pump 14 separate times, end of story. With the advent of CRISPR-Cas9 gene editing in 2012, coinvented by UC Berkeley’s Jennifer Doudna, Whiteman and colleagues Anurag Agrawal of Cornell University and Susanne Dobler of the University of Hamburg in Germany applied to the Templeton Foundation for a grant to recreate these mutations in fruit flies and to see if they could make the flies immune to the toxic effects of cardenolides.

Seven years, many failed attempts and one new grant from the National Institutes of Health later, along with the dedicated CRISPR work of GenetiVision of Houston, Texas, they finally achieved their goal. In the process, they discovered a third critical, compensatory mutation in the sodium pump that had to occur before the last and most potent resistance mutation would stick. Without this compensatory mutation, the maggots died.

Their detective work required inserting single, double and triple mutations into the fruit fly’s own sodium pump gene, in various orders, to assess which ones were necessary. Insects having only one of the two known amino acid changes in the sodium pump gene were best at resisting the plant poisons, but they also had serious side effects — nervous system problems — consistent with the fact that sodium pump mutations in humans are often associated with seizures. However, the third, compensatory mutation somehow reduces the negative effects of the other two mutations.

“One substitution that evolved confers weak resistance, but it is always present and allows for substitutions that are going to confer the most resistance,” said postdoctoral fellow Marianna Karageorgi, a geneticist and evolutionary biologist. “This substitution in the insect unlocks the resistance substitutions, reducing the neurological costs of resistance. Because this trait has evolved so many times, we have also shown that this is not random.”

The fact that one compensatory mutation is required before insects with the most resistant mutation could survive placed a constraint on how insects could evolve toxin resistance, explaining why all 21 lineages converged on the same solution, Whiteman said. In other situations, such as where the protein involved is not so critical to survival, animals might find different solutions.

“This helps answer the question, ‘Why does convergence evolve sometimes, but not other times?'” Whiteman said. “Maybe the constraints vary. That’s a simple answer, but if you think about it, these three mutations turned a Drosophila protein into a monarch one, with respect to cardenolide resistance. That’s kind of remarkable.”

###

The research was funded by the Templeton Foundation and the National Institutes of Health. Co-authors with Whiteman and Agrawal are co-first authors Marianthi Karageorgi of UC Berkeley and Simon Groen, now at New York University; Fidan Sumbul and Felix Rico of Aix-Marseille Université in France; Julianne Pelaez, Kirsten Verster, Jessica Aguilar, Susan Bernstein, Teruyuki Matsunaga and Michael Astourian of UC Berkeley; Amy Hastings of Cornell; and Susanne Dobler of Universität Hamburg in Germany.

Robert Sanders’ Oct. 2, 2019′ news release for the University of California at Berkeley (it’s also been republished as an Oct. 2, 2019 news item on ScienceDaily) has had its headline changed to ‘vomit’ but you’ll find the more vulgar word remains in two locations of the second paragraph of the revised new release.

If you have time, go to the news release on the University of California at Berkeley website just to admire the images that have been embedded in the news release. Here’s one,

Caption: A Drosophila melanogaster “monarch fly” with mutations introduced by CRISPR-Cas9 genome editing (V111, S119 and H122) to the sodium potassium pump, on a wing of a monarch butterfly (Danaus plexippus). Credit & Ccpyright: Julianne Pelaez

Here’s a link to and a citation for the paper,

Genome editing retraces the evolution of toxin resistance in the monarch butterfly by Marianthi Karageorgi, Simon C. Groen, Fidan Sumbul, Julianne N. Pelaez, Kirsten I. Verster, Jessica M. Aguilar, Amy P. Hastings, Susan L. Bernstein, Teruyuki Matsunaga, Michael Astourian, Geno Guerra, Felix Rico, Susanne Dobler, Anurag A. Agrawal & Noah K. Whiteman. Nature (2019) DOI: https://doi.org/10.1038/s41586-019-1610-8 Published 02 October 2019

This paper is behind a paywall.

Words about a word

I’m glad they changed the headline and substituted vomit for puke. I think we need vulgar and/or taboo words to release anger or disgust or other difficult emotions. Incorporating those words into standard language deprives them of that power.

The last word: Genetivision

The company mentioned in the new release, Genetivision, is the place to go for transgenic flies. Here’s a sampling from the their Testimonials webpage,

GenetiVision‘s service has been excellent in the quality and price. The timeliness of its international service has been a big plus. We are very happy with its consistent service and the flies it generates.”
Kwang-Wook Choi, Ph.D.
Department of Biological Sciences
Korea Advanced Institute of Science and Technology


“We couldn’t be happier with GenetiVision. Great prices on both standard P and PhiC31 transgenics, quick turnaround time, and we’re still batting 1000 with transformant success. We used to do our own injections but your service makes it both faster and more cost-effective. Thanks for your service!”
Thomas Neufeld, Ph.D.
Department of Genetics, Cell Biology and Development
University of Minnesota

You can find out more here at the Genetivision website.

Canadian science petition and a science diplomacy event in Ottawa on June 21, 2016*

The Canadian science policy and science funding scene is hopping these days. Canada’s Minister of Science, Kirsty Duncan, announced a new review of federal funding for fundamental science on Monday, June 13, 2016 (see my June 15, 2016 post for more details and a brief critique of the panel) and now, there’s a new Parliamentary campaign for a science advisor and a Canadian Science Policy Centre event on science diplomacy.

Petition for a science advisor

Kennedy Stewart, Canadian Member of Parliament (Burnaby South) and NDP (New Democratic Party) Science Critic, has launched a campaign for independent science advice for the government. Here’s more from a June 15, 2016 announcement (received via email),

After years of muzzling and misuse of science by the Conservatives, our scientists need lasting protections in order to finally turn the page on the lost Harper decade.

I am writing to ask your support for a new campaign calling for an independent science advisor.

While I applaud the new Liberal government for their recent promises to support science, we have a long way to go to rebuild Canada’s reputation as a global knowledge leader. As NDP Science Critic, I continue to push for renewed research funding and measures to restore scientific integrity.

Canada badly needs a new science advisor to act as a public champion for research and evidence in Ottawa. Although the Trudeau government has committed to creating a Chief Science Officer, the Minister of Science – Dr. Kirsty Duncan – has yet to state whether or not the new officer will be given real independence and a mandate protected by law.

Today, we’re launching a new parliamentary petition calling for just that: https://petitions.parl.gc.ca/en/Petition/Sign/e-415

Can you add your name right now?

Canada’s last national science advisor lacked independence from the government and was easily eliminated in 2008 after the anti-science Harper Conservatives took power.

That’s why the Minister needs to build the new CSO to last and entrench the position in legislation. Rhetoric and half-measures aren’t good enough.

Please add your voice for public science by signing our petition to the Minister of Science.

Thank you for your support,

Breakfast session on science diplomacy

One June 21, 2016 the Canadian Science Policy Centre is presenting a breakfast session on Parliament Hill in Ottawa, (from an announcement received via email),

“Science Diplomacy in the 21st Century: The Potential for Tomorrow”
Remarks by Dr. Vaughan Turekian,
Science and Technology Adviser to Secretary of State John Kerry

Event Information
Tuesday, June 21, 2016, Room 238-S, Parliament Hill
7:30am – 8:00am – Continental Breakfast
8:00am – 8:10am – Opening Remarks, MP Terry Beech
8:10am – 8:45am – Dr. Vaughan Turekian Remarks and Q&A

Dr. Turekian’s visit comes during a pivotal time as Canada is undergoing fundamental changes in numerous policy directions surrounding international affairs. With Canada’s comeback on the world stage, there is great potential for science to play an integral role in the conduct of our foreign affairs.  The United States is currently one of the leaders in science diplomacy, and as such, listening to Dr.Turekian will provide a unique perspective from the best practices of science diplomacy in the US.

Actually, Dr. Turekian’s visit comes before a North American Summit being held in Ottawa on June 29, 2016 and which has already taken a scientific turn. From a June 16, 2016 news item on phys.org,

Some 200 intellectuals, scientists and artists from around the world urged the leaders of Mexico, the United States and Canada on Wednesday to save North America’s endangered migratory Monarch butterfly.

US novelist Paul Auster, environmental activist Robert F. Kennedy Jr., Canadian poet [Canadian media usually describe her as a writer] Margaret Atwood, British writer Ali Smith and India’s women’s and children’s minister Maneka Sanjay Gandhi were among the signatories of an open letter to the three leaders.

US President Barack Obama, Canadian Prime Minister Justin Trudeau and Mexican President Enrique Pena Nieto will hold a North American summit in Ottawa on June 29 [2016].

The letter by the so-called Group of 100 calls on the three leaders to “take swift and energetic actions to preserve the Monarch’s migratory phenomenon” when they meet this month.

In 1996-1997, the butterflies covered 18.2 hectares (45 acres) of land in Mexico’s central mountains.

It fell to 0.67 hectares in 2013-2014 but rose to 4 hectares this year. Their population is measured by the territory they cover.

They usually arrive in Mexico between late October and early November and head back north in March.

Given this turn of events, I wonder how Turekian, given that he’s held his current position for less than a year, might (or might not) approach the question of Monarch butterflies and diplomacy.

I did a little research about Turekian and found this Sept. 10, 2016 news release announcing his appointment as the Science and Technology Adviser to the US Secretary of State,

On September 8, Dr. Vaughan Turekian, formerly the Chief International Officer at The American Association for the Advancement of Science (AAAS), was named the 5th Science and Technology Adviser to the Secretary of State. In this capacity, Dr. Turekian will advise the Secretary of State and the Under Secretary for Economic Growth, Energy, and the Environment on international environment, science, technology, and health matters affecting the foreign policy of the United States. Dr. Turekian will draw upon his background in atmospheric chemistry and extensive policy experience to promote science, technology, and engineering as integral components of U.S. diplomacy.

Dr. Turekian brings both technical expertise and 14 years of policy experience to the position. As former Chief International Officer for The American Association for the Advancement of Science (AAAS) and Director of AAAS’s Center for Science Diplomacy, Dr. Turekian worked to build bridges between nations based on shared scientific goals, placing special emphasis on regions where traditional political relationships are strained or do not exist. As Editor-in-Chief of Science & Diplomacy, an online quarterly publication, Dr. Turekian published original policy pieces that have served to inform international science policy recommendations. Prior to his work at AAAS, Turekian worked at the State Department as Special Assistant and Adviser to the Under Secretary for Global Affairs on issues related to sustainable development, climate change, environment, energy, science, technology, and health and as a Program Director for the Committee on Global Change Research at the National Academy of Sciences where he was study director for a White House report on climate change science.

Turekian’s last editorial for Science & Diplomacy dated June 30, 2015 features a title (Evolving Institutions for Twenty-First Century [Science] Diplomacy) bearing a resemblance to the title for his talk in Ottawa and perhaps it provides a preview (spoilers),

Over the recent decade, its treatment of science and technology issues has increased substantially, with a number of cover stories focused on topics that bridge science, technology, and foreign affairs. This thought leadership reflects a broader shift in thinking within institutions throughout the world about the importance of better integrating the communities of science and diplomacy in novel ways.

In May, a high-level committee convened by Japan’s minister of foreign affairs released fifteen recommendations for how Japan could better incorporate its scientific and technological expertise into its foreign policy. While many of the recommendations were to be predicted, including the establishment of the position of science adviser to the foreign minister, the breadth of the recommendations highlighted numerous new ways Japan could leverage science to meet its foreign policy objectives. The report itself marks a turning point for an institution looking to upgrade its ability to meet and shape the challenges of this still young century.

On the other side of the Pacific, the U.S. National Academy of Sciences released its own assessment of science in the U.S. Department of State. Their report, “Diplomacy for the 21st Century: Embedding a Culture of Science and Technology Throughout the Department of State,” builds on its landmark 1999 report, which, among other things, established the position of science and technology adviser to the secretary of state. The twenty-seven recommendations in the new report are wide ranging, but as a whole speak to the fact that while one of the oldest U.S. institutions of government has made much progress toward becoming more scientifically and technologically literate, there are many more steps that could be taken to leverage science and technology as a key element of U.S. foreign policy.

These two recent reports highlight the importance of foreign ministries as vital instruments of science diplomacy. These agencies of foreign affairs, like their counterparts around the world, are often viewed as conservative and somewhat inflexible institutions focused on stability rather than transformation. However, they are adjusting to a world in which developments in science and technology move rapidly and affect relationships and interactions at bilateral, regional, and global scales.

At the same time that some traditional national instruments of diplomacy are evolving to better incorporate science, international science institutions are also evolving to meet the diplomatic and foreign policy drivers of this more technical century. …

It’s an interesting read and I’m glad to see the mention of Japan in his article. I’d like to see Canadian science advice and policy initiatives take more notice of the rest of the world rather than focusing almost solely on what’s happening in the US and Great Britain (see my June 15, 2016 post for an example of what I mean). On another note, it was disconcerting to find out that Turekian believes that we are only now moving past the Cold War politics of the past.

Unfortunately for anyone wanting to attend the talk, ticket sales have ended even though they were supposed to be open until June 17, 2016. And, there doesn’t seem to be a wait list.

You may want to try arriving at the door and hoping that people have cancelled or fail to arrive therefore acquiring a ticket. Should you be an MP (Member of Parliament), Senator, or guest of the Canadian Science Policy Conference, you get a free ticket. Should you be anyone else, expect to pay $15, assuming no one is attempting to scalp (sell one for more than it cost) these tickets.

*’ … on June’ in headline changed to ‘ … on June 21, 2016’ on June 17, 2016.