News / Science & Technology

Scientists Draw First Genetic Roadmap of Amphibian

X. tropicalis (left) and X. laevis (right)
X. tropicalis (left) and X. laevis (right)
Jessica Berman

Scientists have completed the first genetic blueprint of an amphibian, a clawed African frog, which they say is among the last vertebrates to have its DNA sequenced.  Researchers hope the work will shed light on the effects of chemicals called endocrine disruptors on humans and help preserve endangered frog species.  

Xenopus tropicalis, often called the Western clawed frog, is one of 20 frog species native to sub-Saharan Africa.  Its cousin, X. laevis, is now commonly used in laboratories where studies of its large eggs have helped scientists understand the development of fertilized eggs into embryos.

With its genetic sequence now in hand, the smaller tropicalis should help researchers link genetic changes to the developmental milestones in both species as well as in human embryos, which scientists say are more difficult to study.

Uffe Hellsten, with the Department of Energy Joint Genome Institute in Walnut Creek, California, is one of almost 50 scientists worldwide who helped to create the new catalog of the frog's DNA.

Hellsten says the genetic blueprint opens up several other avenues of research by comparing the tropicalis' genes to those of other vertebrates, including humans. "To mention an example, we have found that about 80 percent of all genes that are known to be associated with human disease have a counterpart in frog.  Obviously this opens up the possibility of enhancing our understanding of many of those diseases by studying disease models in frog," he said.

Scientists say tropicalis and humans share 1,700 disease-related genes. They say the frog gives scientists a living laboratory in which to learn how those genes cause illness in people.

Hellsten notes that a  comparison of regions around specific genes in the frog, chicken and human shows that all three genomes are remarkably similar. He says scientists are looking at fragments of an ancient chromosome that belonged to the common ancestor of all mammals, birds and amphibians before they diverged 360 million years ago.

Hellsten says tropicalis has about 20,000 genes compared to 23,000 genes in human.  The frog shares many biological features with humans, including development of nervous, skeletal and immune systems.

In general, frogs are popular research subjects because they take up less room in the lab and have a shorter lifecycle, as little as 4 months, and their eggs are relatively easy to manipulate.

Frogs rose to prominence as prized experimental animals in the 1940's when scientists discovered they could inject the urine of pregnant woman into a frog and it would produce eggs.

Since then, there's been interest in frogs as models for the study of endocrine disruptors. These artificial chemicals - found in industrial products such as agricultural insecticides - often pollute the lakes and streams in which the frogs live.

The endocrine disruptors mimic the frogs' reproductive hormones, causing bizarre deformities in developing amphibians, including the growth of female sex organs in male frogs.  The chemicals are also blamed for causing a major decline in frog populations over the past several decades.

As a result, says Hellsten, scientists are eager to figure out exactly how these chemicals do their damage. "We can hope to actually study the effect of such disruptors at a molecular level and understand better how they interact.  And research like this could hopefully in time not only help humans, because humans are also sensitive to such chemicals, but also help preserve the frog diversity," he said.

The complete genetic road map of the African frog Xenopus tropicalis is published this week in the journal Science.

You May Like

US Storm Falls Short of Severe Predictions, Yet Affects Millions

NYC mayor says, 'This is nothing like we feared it would be,' yet blizzard warnings, travel bans remain for several East Coast states More

Millions of Displaced Nigerians Struggle with Daily Existence

Government acknowledges over a million people were displaced in 2014 due to fight against Boko Haram insurgency More

Facebook: Internal Error to Blame for Outages

Temporary outage appeared to spill over and temporarily slow or block traffic to other major Internet sites More

This forum has been closed.
Comments
     
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Obama Urges Closer Economic Ties During Historic India Visiti
X
Aru Pande
January 26, 2015 9:33 PM
U.S. President Barack Obama says the United States and India must do better to capitalize on untapped potential in their economic relationship - by removing some of the roadblocks to greater trade and investment. As VOA correspondent Aru Pande reports from New Delhi, Obama spoke after participating in India’s Republic Day celebration.
Video

Video Obama Urges Closer Economic Ties During Historic India Visit

U.S. President Barack Obama says the United States and India must do better to capitalize on untapped potential in their economic relationship - by removing some of the roadblocks to greater trade and investment. As VOA correspondent Aru Pande reports from New Delhi, Obama spoke after participating in India’s Republic Day celebration.
Video

Video US, EU Threaten New Russia Sanctions Over Ukraine

U.S. President Barack Obama has blamed Russia for an attack by Ukrainian separatists that left dozens dead in the port of Mariupol and cast further doubt on the viability of last year’s cease-fire with the Kyiv government. VOA’s Michael Bowman reports from Washington.
Video

Video White House Grapples With Yemen Counterterrorism Strategy

Reports say the U.S. has carried out a drone strike on suspected militants in Yemen, the first after President Barack Obama offered reassurances the U.S. is continuing its counterterrorism operations in the country. The future of those operations has been in question following the collapse last week of Yemen’s government. VOA White House correspondent Luis Ramirez reports.
Video

Video Kerry Warns Against Violence in Nigeria Election

US Secretary of State John Kerry visited Nigeria Sunday in a show of the level of concern within the U.S. and the international community over next month’s presidential election. Chris Stein reports.
Video

Video Zoo Animals Show Their Artistic Sides

The pursuit of happiness is so important, America's founding fathers put it in the Declaration of Independence. Any zookeeper will tell you animals need enrichment, just like humans do. So painting, and even music, are part of the Smithsonian National Zoo's program to keep the animals happy. VOA’s June Soh met some animal artists at the zoo in Washington. Faith Lapidus narrates.
Video

Video Worldwide Photo Workshops Empower Youth

Last September, 20 young adults from South Sudan took part in a National Geographic Photo Camp. They are among hundreds of students from around the world who have learned how to use a camera to tell the stories of the people in their communities through the powerful medium of photography. Three camp participants talked about their experiences recently on a visit to Washington. VOA’s Julie Taboh reports.
Video

Video Saudi, Yemen Developments Are Sudden Complications for Obama

The death of Saudi Arabia's King Abdullah and the collapse of Yemen’s government have cast further uncertainty on U.S. efforts to fight militants in the Middle East and also contain Iran’s influence in the region. VOA White House correspondent Luis Ramirez reports on the new complications facing the Obama administration and its Middle East policy.
Video

Video Progress, Some Areas of Disagreement in Cuba Talks

U.S. and Cuban officials are reporting progress from initial talks in Havana on re-establishing diplomatic ties. U.S. Assistant Secretary of State (for Western Hemisphere Affairs) Roberta Jacobson said while there was agreement on a broad range of issues, there also are some “profound disagreements” between Washington and Havana. VOA State Department correspondent Pam Dockins has the story.
Video

Video US, Japan Offer Lessons as Eurozone Launches Huge Stimulus

The Euro currency has fallen sharply after the European Central Bank announced a bigger-than-expected $67 billion-a-month quantitative easing program Thursday - commonly seen as a form of printing new money. Henry Ridgwell reports for VOA from London on whether the move might rescue the eurozone economy -- and what lessons have been learned from similar programs around the world.
Video

Video Nigerian Elections Pose Concern of Potential Conflict in 'Middle Belt'

Nigeria’s north-central state of Kaduna has long been the site of fighting between Muslims and Christians as well as between people of different ethnic groups. As the February elections approach, community and religious leaders are making plans they hope will keep the streets calm after results are announced. Chris Stein reports from the state capital, Kaduna.
Video

Video As Viewership Drops, Obama Puts His Message on YouTube

Ratings reports show President Obama’s State of the Union address this week drew the lowest number of viewers for this annual speech in 15 years. White House officials anticipated this, and the president has decided to take a non-traditional approach to getting his message out. VOA White House correspondent Luis Ramirez reports.
Video

Video S. Korean Businesses Want to End Trade Restrictions With North

Business leaders in South Korea are calling for President Park Geun-hye to ease trade restrictions with North Korea that were put in place in 2010 after the sinking of a South Korean warship.Pro-business groups argue that expanding trade and investment is not only good for business, it is also good for long-term regional peace and security. VOA’s Brian Padden reports.

Circumventing Censorship

An Internet Primer for Healthy Web Habits

As surveillance and censoring technologies advance, so, too, do new tools for your computer or mobile device that help protect your privacy and break through Internet censorship.
More

All About America

AppleAndroid