Arlington Citizen-Journal

UT Arlington researcher finishes genome sequencing of Burmese python

Todd’s baby is a Burmese python.

Technically the study of the snake’s genomes is his baby.

University of Texas at Arlington evolutionary biologist Todd Castoe studies snakes to see how they evolved from lizards into slithering strong-jawed reptiles.

He happened to lead author a recent scientific article — the first of its kind — on the Burmese python genome.

Castoe is now looking for answers on how the snakes have extensively evolved over such a relatively short period of time.

The Fort Worth Star-Telegram spoke with Castoe in June, for a different genome project he worked on with Matthew Fujita of UT Arlington. The two co-authored a paper in the journal Genome Biology about how a Western painted turtle’s genes allow them to tolerate frigid temperatures and oxygen deprivation.

The evolutionary biologist’s recent work on pythons was published by the Proceedings of the National Academy of Sciences in early December, and now he is working to answer questions like how the snake, which only eats a few times a year, is able to ramp up its metabolism to 40 times its normal rate within days after consumption.

The UT Arlington assistant biology professor explained that genomes are the sequence of all the genetic material from an organism.

Early in snake evolution, an overwhelming amount of functional changes in genes happened in a concentrated period of time, Castoe said. The paper points this fact out for the first time and asks the question of how it happened.

Castoe looks at what genes are turned on and off before and after a python eats. By doing so they can pinpoint the subset of genes that are at work when the heart is growing 50 percent in size.

“Snakes and humans have about 25,000 genes, and they are relatively similar,” Castoe said. “If we can understand what genes a python uses to grow its heart, we might be able to find out how to turn our versions of those same genes on to grow or repair hearts.”

Snakes are able to grow not only their hearts, but kidneys, livers and guts twice in size within 24-48 hours of eating.

Castoe also helped author a paper on the king cobra, and the two companion papers are the first snake genomes ever done.

“Identifying the link between the change in a gene and the change in a physical characteristic is a really fundamentally important and hot topic that has been around for a number of years,” he said.

Castoe started his work under the direction of evolutionary biologist David Pollock, the last author of the paper, while a postdoctoral student at the University of Colorado School of Medicine. He began studying the unique metabolic genes snakes have, ones that separate them from any other vertebrate.

When Castoe found out a group in the Netherlands was sequencing the king cobra’s genome, he decided to pair his research.

“We got in touch and it turns out we were able to cross-fertilize data,” Castoe said.

Now Castoe will continue his research with graduate students at UT Arlington to dig deep into what the genome sequencing can mean for humans.

He and his graduate students are sampling more physically primitive snakes, ones that diverged from the python very early, to understand what happened early in snake evolution. He’ll also study other species of snakes that do and do not experience dramatic remodeling of physiology like the python.