Quantcast

Meet the First Gene-Edited Reptile: An Albino Lizard

Science
Lizard surgery and oocyte microinjection procedure. Cell Reports

By Malavika Vyawahare

Think of a reptile that's been genetically mutated, and Godzilla springs to mind. Or maybe ninja turtles.


But the real thing is here, and it's neither hell-bent on destroying Tokyo nor eating pizza in the sewers. Instead, it's a pale, finger-sized lizard — the world's first gene-edited reptile, researchers at the University of Georgia reported this week.

In a paper published in the journal Cell Reports, Douglas B. Menke and his colleagues described how they made an albino version of the brown anole (Anolis sagrei), a species of lizard native to Cuba and the Bahamas.

"Instead of performing gene-editing on fertilized eggs or single-cell embryos, we performed gene-editing on unfertilized eggs while they are still physically attached to the ovary of adult female lizards," said Menke, a geneticist and developmental biologist.

The first genetically modified animal was a transgenic mouse, created in 1974. But it was only seven years later that researchers could edit genes that were passed on to future generations. In the case of the albino lizard, the changes are inheritable.

Though gene editing has been around for decades and the advent of CRISPR technology makes it easier and is more efficient to carry out, doing so in reptilian zygotes is particularly challenging. Researchers consider it best to make an edit when the embryo is newly formed. For animals that reproduce sexually, the target is usually a single cell at this stage.

In reptiles, it's difficult to pin down when fertilization actually happens, in large part due to internal fertilization and sperm storage, where females can store sperm for extended periods. In A. sagrei lizards, the females can store sperm for more than two months.

The Anolis genus, which includes more than 400 species, is native to Central and South America and the Caribbean islands. Brown anole lizards are widely distributed beyond their native Cuba and Bahamas because they're a highly invasive species. The lizards used in the experiment were caught from the wild in Orlando, Florida.

The scientists performed surgery to insert gene-editing reagents into 146 unfertilized eggs of 21 adult female lizards. The females were then mated with adult males. A fraction of the resulting offspring carried the mutation, which manifested as albinism. The edit is unlikely to be lethal to the animals.

The downside of manipulating the egg and not the embryo is that it doesn't host the paternal DNA, reducing the chances that the edit will manifest in the offspring. For their study, the authors had to wait for three months for the lizard eggs to hatch to verify whether their editing method had induced the desired mutation.

Only about 6 to 9 percent of the eggs in which the edit was introduced produced mutant lizards. This is low when compared to other methods that report efficiencies of 80 percent or more. However, being able to produce the change in those few individuals is itself a breakthrough. The authors say the efficiency can be boosted by targeting larger eggs (more than 0.75 mm in diameter), which had the highest success rate in this experiment.

Editing genes is one of the key ways to deduce what role they play and which traits they're associated with. The University of Georgia researchers are already exploring different gene functions in Anolis lizards and say they hope this will aid in the study of genetic defects in humans. For example, people with albinism are also likely to have poor eyesight due to defects in a part of the eye called the fovea. Mice that are widely used for genetic studies don't have a fovea and so studying in albinism in mice may not shed light on the link between albinism and impaired vision.

Gene editing can also be used to curb invasive species populations. Its most widely known application is to control mosquito populations, but with advances in gene editing this could be extended to invasive reptiles as well.

"There are over 10,000 described species of reptile, and the genome of each species contains around 25,000 protein-coding genes. There is a whole universe of unstudied biology in these animals," Menke said. "We hope that other research groups will adapt our gene-editing method to investigate gene function in additional reptile species."

Reposted with permission from our media associate Mongabay.

EcoWatch Daily Newsletter

Individual standing in Hurricane Harvey flooding and damage. Jill Carlson / Flickr / CC BY 2.0

By Allegra Kirkland, Jeremy Deaton, Molly Taft, Mina Lee and Josh Landis

Climate change is already here. It's not something that can simply be ignored by cable news or dismissed by sitting U.S. senators in a Twitter joke. Nor is it a fantastical scenario like The Day After Tomorrow or 2012 that starts with a single crack in the Arctic ice shelf or earthquake tearing through Los Angeles, and results, a few weeks or years later, in the end of life on Earth as we know it.

Read More Show Less
A pregnant woman works out in front of the skyline of London. SHansche / iStock / Getty Images Plus

Air pollution particles that a pregnant woman inhales have the potential to travel through the lungs and breach the fetal side of the placenta, indicating that unborn babies are exposed to black carbon from motor vehicles and fuel burning, according to a study published in the journal Nature Communications.

Read More Show Less
Sponsored

Teen activist Greta Thunberg delivered a talking-to to members of Congress Tuesday during a meeting of the Senate Climate Change Task Force after politicians praised her and other youth activists for their efforts and asked their advice on how to fight climate change.

Read More Show Less
Ten feet of water flooded 20 percent of this Minot, North Dakota neighborhood in June 2011. DVIDSHUB / CC BY 2.0

By Jared Brey

When Hurricane Michael tore through the Florida panhandle last October, it killed at least 43 people, caused an estimated $25 billion in damage and destroyed thousands of homes.

Read More Show Less
A protestor holds up her hand covered with fake oil during a demonstration on the U.C. Berkeley campus in May 2010. Justin Sullivan / Getty Images

The University of California system will dump all of its investments from fossil fuels, as the Associated Press reported. The university system controls over $84 billion between its pension fund and its endowment. However, the announcement about its investments is not aimed to please activists.

Read More Show Less
Sponsored
Forest fire continues to blaze in Indonesesia on Sept. 18. WAHYUDI / AFP / Getty Images

Nearly 200 people have been arrested in Indonesia over their possible connections to the massive wildfires raging in the nation's forest, officials said this week.

Read More Show Less

By Ngozi Okonjo-Iweala

World leaders have a formidable task: setting a course to save our future. The extreme weather made more frequent and severe by climate change is here. This spring, devastating cyclones impacted 3 million people in Mozambique, Malawi and Zimbabwe. Record heatwaves are hitting Europe and other regions — this July was the hottest month in modern record globally. Much of India is again suffering severe drought.

Read More Show Less
Covering Climate Now / YouTube screenshot

By Mark Hertsgaard

The United Nations Secretary General says that he is counting on public pressure to compel governments to take much stronger action against what he calls the climate change "emergency."

Read More Show Less