Showing posts with label brown anole. Show all posts
Showing posts with label brown anole. Show all posts

Sunday, 29 September 2019

Lizards gone wild! UC Berkeley researcher’s ‘feminist science’ bucks male-dominated inquiry – via Herp Digest



Did male scientists slut-shame a small tropical reptile?

By Ethan Brown, Bay Area News Group

For as long as humans have practiced science, men have dominated research. Much of our understanding of the world has been filtered through their beliefs. For UC Berkeley post-doctoral researcher Ambika Kamath, that’s a problem.

The behavioral ecologist studies Anolis sagrei, the brown anole, a small lizard native to the Caribbean and introduced in Florida. For years, it was widely believed that this reptile was territorial, and that females would mate only with the male whose area they occupied. When women scientists first found evidence that might not be the case, their conclusions were dismissed, their findings deemed exceptions, and their papers rejected, Kamath says.

But Kamath, through observation, DNA analysis, mathematical modeling and “feminist science,” determined that the lady lizards were actually, so to speak, pretty hot to trot, despite male researchers’ inability to recognize — or even look for — behavior she says conflicted with closely held male beliefs about female sexual behavior. Those biases, which go back to Charles Darwin and beyond, continue to influence how science is done, and the conclusions that are reached, she says.

This news organization sat down with Kamath in her lab to talk about how her practice of feminist science turned accepted knowledge on its head, and why a diversity of perspectives is important to scientific inquiry. Her answers have been edited for length and clarity.

Q: If feminist science is science through a feminist lens, what have been the traditional lenses in science?

A: They end up being lenses of whatever culture or demographic is dominant. Currently, the dominant global scientific tradition is one that has largely been white, largely been male, largely been people who are rich. Those are the people who have practiced a lot of the science on which a lot of what mainstream science today is built.

Q: What have been the effects of that traditional approach on our understanding?

A: Very often when you study an animal population it’s (considered) OK to just study the males and not study the females. The lizards that I worked on, Anolis lizards, for the longest time things that we stated as generalities about the species or the genus were things that were known only in males and no one thought twice about that. Most practitioners of biology were men. Another aspect of this that is very dominant in research into the evolution of animal behavior is importing stereotypes of males and females from the human world and projecting those onto the animals that we study. A long-standing one, that was famously formalized by Darwin, was this notion that females are coy and passive in sexual interactions and males are not.

Q: Are there risks to practicing feminist science, in the way that it’s perceived or received?

A: I don’t think it serves scientists well to pretend that the scientific process is perfect or infallible. None of this should be interpreted as challenging the scientific process in and of itself. There’s a huge difference between broadening science to include a marginalized perspective that goes against the status quo, versus preserving the already powerful voice that seeks to marginalize. We’re doing better science if we’re asking questions from different perspectives as opposed to just one. And we’re doing better science if we think about the ways in which who we are influences the questions we ask. That’s the beauty of science, it’s these incremental steps toward something that is hopefully true.

Q: Why wasn’t it understood that female anoles could be promiscuous?

A: In Anolis lizards the long-standing paradigm for their social organization was one of territoriality — females would just mate with the one male in whose territory they lived. These sorts of inferences about mating patterns from behavioral descriptions were true of animals across the board. In the ’90s or so people started to be able to use genetic methods to infer actual mating patterns using the same methods that people use for paternity tests. They started to find that much much more often than was expected based on those behavioral descriptions, females were mating with multiple males. We saw this hugely in birds. It’s been described in the literature very often as ‘adultery’ — that’s a very clear example of the ways in which we take non-neutral terminology of how we talk about ourselves and import it onto animals.

Q: What criticism do you get for practicing feminist science?

A: There are people that say … we would have figured this out without making a fuss. People really object to the fuss. People also think that it’s incredibly disrespectful to the work of previous scientists to question it in this fashion. Once I was giving a seminar and someone said, ‘You’re supposed to stand on the shoulders of giants, you can’t kick them in the ankles.’ Very graciously, another senior academic said, ‘Well, what if those giants are standing in three feet of mud?’

Q: Is there a risk that if you’re applying a feminist lens that you’re going to miss something in the same way male scientists did?

A: What we’re looking for is as many lenses as possible. Science is not the work of single lone geniuses. Sure there are geniuses. But their perspective is still one perspective. When you’re non-mainstream in terms of the questions that you’re asking, you’re automatically going to get more people saying, ‘Oh, you have an agenda.’ And because you’ve got people saying, ‘Oh, you have an agenda,’ you have to do that much more work to hold yourself to a higher standard.

Friday, 26 April 2019

UGA scientists create world’s first gene-edited lizards – via Herp Digest


UGA Press Release by Michael Terrazas 4/3/19
A group of University of Georgia researchers led by geneticist Douglas Menke has become the first in the world to successfully produce a genetically modified reptile—specifically, four albino lizards—using the CRISPR-Cas9 gene-editing tool. The team’s results, which appeared online March 31, have been submitted for peer review.
“Reptiles are very understudied in terms of their reproductive biology and embryonic development,” said Menke, associate professor in the department of genetics. “There are no good methods to manipulate embryos like we can easily do with mammals, fish or amphibians. To our knowledge, no other lab in the world has produced a genetically altered reptile.”
Gene manipulation using CRISPR typically involves injecting gene-editing solutions into an animal’s newly fertilized egg or single-cell embryo, causing a mutation in the DNA that is reproduced in all subsequent cells. However female reptiles can store sperm in their oviducts for long periods, making it difficult to pinpoint the exact moment of fertilization. Also, the physiology of their fertilized eggs, which have pliable shells with no air space inside, presents challenges for manipulating embryos without damaging them.
Working with the species Anolis sagrei, commonly called the brown anole, Menke’s team overcame these challenges by microinjecting CRISPR proteins into multiple immature eggs, or oocytes, still located in the lizards’ ovaries. Targeting the tyrosinase gene, they successfully injected 146 oocytes from 21 lizards, then waited for the oocytes to be fertilized naturally. Within a few weeks, they realized their goal: four offspring displaying the telltale trait of albinism, which results when tyrosinase is inactivated.
“When I saw our first albino hatchling, it was truly awe inspiring,” said D.V.M./Ph.D. student Ashley Rasys, who was first author on the study. “I’m most excited about the possibility of expanding this approach into many other reptilian model systems, effectively opening the doorway for future functional studies.”
Menke, who typically studies mice, said he chose brown anoles because they essentially represent a reptilian counterpart to Darwin’s famous Galapagos finches—the lizards are spread throughout the islands of the Caribbean, with distinctive traits arising among each island’s relatively isolated population. Leg size, for example, is highly variable among different species of anoles, with ground-dwelling species possessing big and strong legs adapted to running and leaping, while their tree-dwelling cousins have smaller legs that are more agile for limb-hopping. The lizards for this study were all collected from the wild in an area near Orlando, Florida.
The ability to study the genes of brown anoles could also have implications for human genetics work. The tyrosinase gene is required for certain aspects of eye development shared between humans and anoles, but absent in the eyes of mice and other organisms commonly used for biomedical research. Researchers looking to explore ways to manipulate this gene for human ocular health did not have a suitable animal model—until now.
As an added bonus, Menke’s team noted that the mutant anoles not only displayed the manipulated tyrosinase in the gene copies inherited from their mother, but from the father as well. This means that the CRISPR reagent likely remained active in the mother’s oocytes much longer than anticipated and mutated the paternal genes post-fertilization.
“That was a surprise,” Menke said. “It enabled us to see the functional requirements of the gene without having to breed mutated animals to produce offspring who inherit the mutated gene from both parents. It’s a big time-saver.”
“This work could have far-reaching impact not only for the study of reptile genetics but also for the advancement of genomic medicine and application in humans,” said David Lee, UGA vice president for research. “I applaud Dr. Menke and his colleagues on this very significant achievement.”
Additional co-authors on the study include James Lauderdale, associate professor in the department of cellular biology; research staff members Sungdae Park and Rebecca Ball; and graduate student Aaron Alcala. The research was primarily supported by grants from the National Science Foundation’s Enabling Discovery through GEnomic Tools (EDGE) program and from the Society for Developmental Biology.


Monday, 12 February 2018

Speedy Lizard Outraces Global Warming-A Bahamanian lizard has shown the ability to adapt to higher temperatures – via Herp Digest


By Niina Heikkinen, ClimateWire on September 18, 2014

Species like the brown anole lizard maintain their body temperature by moving between sunny and shady areas, in a process called behavioral thermoregulation. Credit: Ken Thomas via Wikimedia Commons

The brown anole lizard in the Bahamas is raising questions about whether some cold-blooded species may be able to adapt to global warming.

Scientists consider cold-blooded species particularly vulnerable to climate change because of their sensitivity to even small temperature shifts. Species like the brown anole lizard maintain their body temperature by moving between sunny and shady areas, in a process called behavioral thermoregulation.

Because these species move between "microhabitats" to avoid overheating, some researchers believe that they don't face adaptive pressures that would favor the survival of individuals with greater heat tolerance. This is bad news for cold-blooded species. If they are unable to adapt, then rising temperatures will lead to their extinction.

"The potential for the organisms to evolve in response to a rapidly changing environment is often downplayed, even though very few studies have examined the extent to which species might adapt," said Michael Logan, who recently received a Ph.D. from Dartmouth College and is now a postdoctoral fellow at the National Science Foundation.

Logan and two other scientists from Dartmouth and the University of Virginia set out to test the adaptive pressures of simulated climate change conditions on brown anole lizards (Anolis sagrei).

The researchers captured and transplanted about 100 male lizards from their forest habitat to a hotter area with greater temperature variability about half a mile away. Then the researchers tested how fast the lizards could sprint at a range of temperatures. The researchers published their results in the Proceedings of the National Academy of Sciences, with Logan as lead author.

Running quickly comes naturally to the brown anole lizards. "They are the Usain Bolts of the lizard world," said study co-author Ryan Calsbeek, an associate professor at Dartmouth, referring to the record-breaking Jamaican sprinter. The lizards need to move quickly to hunt for food and to avoid predators, and previous research has shown that their sprint speed is strongly correlated with survival and reproductive success.

Before each sprint, the researchers placed the lizards in an incubator to adjust their body temperature, then had them run as fast as they could along a short track. Each lizard did five sprint trials for each temperature, with a two-hour break between each sprint.

After the initial tests, the lizards were released, and the surviving lizards were recaptured at the end of the breeding season. The researchers then compared the results to another 100 male lizards they used as controls.

"We weren't at all sure whether we would see selection when we started this study. If I had to put money on it, I would have bet against it," Logan said.

Just 22 percent of the transplanted lizards and 45 percent of the control lizards survived the breeding season.

When the researchers analyzed their data, the results showed clear selection pressure in favor of the most heat-tolerant lizards in the transplanted lizards, but no trend among the controls.

"The individuals that ran the fastest at the warmest body temperature and those that ran at the broadest range of temperatures did the best," Logan said of the transplanted group.

Their research is the first time that thermal performance has been used as part of the framework of measuring selection and heritability in cold-blooded species, according to the researchers.

"I was surprised that the selection was as strong as it was. Often when you measure selection in nature, it's at a very low magnitude," said co-author Robert Cox, an assistant professor at the University of Virginia in Charlottesville. "The fact that the expectation and the results match so well gives us assurance that it's actually happening.”

The study did not show whether these traits could be passed on to future generations. If the traits are heritable, that could mean the lizards may be able to rapidly evolve to climate change pressures, which would be good news for the species.

Cox's laboratory in Charlottesville is now investigating whether the lizards are able to pass on the ability to run fast at higher temperatures and at a broader range of temperatures to their offspring. If they can, then it would appear the lizards could rapidly evolve in response to climate change, according to the researchers.

Testing heritability is easier in laboratory conditions because all the animals are raised in the same environment and the researchers know the relatedness of all the lizards, Cox said.

Calsbeek said he did not want the study's results to be misinterpreted. "This is not us saying that climate change is not a problem," he said. It's also unclear whether other cold-blooded species may also be able to adapt.

"Because there have been no other studies to look at these particular traits, it's hard to tell how broadly applicable it would be," Calsbeek said.

Luke Mahler, a researcher at the University of California, Davis, who studies evolution patterns in Anolislizards, is also skeptical about how broadly the researchers' results could apply even among the nearly 400 other lizard species within the Anolis genus.

"I think it's a stretch to suggest more generally that tropical animal populations may be capable of rapid adaptation to anthropogenic warming," said Mahler, who is also co-chairman of the Anoline Lizard Specialist Group, which studies which anole lizard species are at risk of extinction at the International Union for Conservation of Nature.

"The reason I worry about this suggestion is because Anolis sagrei is hardy, abundant, widespread and tolerant of lots of temperatures. It occurs naturally over a wide range of thermal environments, and has experienced such variety over millions of years. What this means is that the species probably has loads of heritable variation in thermal tolerance for natural selection to work on," Mahler said.

By comparison, phenacosaur anoles living in cloud forests have had very little exposure to temperature variability for over 10 million years and are very much at risk from climate change, he said.

Still, the study does provide convincing evidence that there is natural selection for thermal performance traits.

"It's great to see an answer to the important question of whether behavior always prevents tropical animals from adapting to climate change," he said. "I think in this case, we have satisfying evidence that the answer is ‘no.’"



Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC.
Related Posts with Thumbnails

ShareThis