Essential Science: How pythons regenerate their organs

Posted Jun 26, 2017 by Tim Sandle
Pythons are remarkable in many ways and this includes the ability to regenerate their organs. Unlocking the genetic secret of this could aid medics who seek to improve the way people, recover from injuries.
Burmese python (Python molurus bivittatus)
Burmese python (Python molurus bivittatus)
Karunakar Rayker
Snakes are fascinating in other ways, as well as being able to regenerate their organs, most snakes can produce venom. Researchers have carried out a comprehensive review of these abilities using genetic sequencing. This has been aided by advanced computing and big data crunching, to help analyze information collected about the genome. A genome is the genetic material of an organism. It consists of DNA, including both the genes (the coding regions), the noncoding DNA. Each genome contains all of the information needed to build and maintain that organism.
The structure of the DNA
The structure of the DNA
Zephyris / Wikipedia
By using supercomputers, and advanced DNA sequencing and analysis, scientists from University of Texas at Austin have identified a number of genes connected with organ growth in Burmese pythons. A similar comparison has been carried out in rattlesnake species. The Burmese python (Python bivittatus) is one of the five largest species of snakes in the world (about the third-largest as measured either by length or weight). It is native to a large area of tropical South and Southeast Asia.
File photo: Pythons have the ability to unhinge their jaws to swallow prey.
File photo: Pythons have the ability to unhinge their jaws to swallow prey.
Tim Vickers
Through this work the U.S. researchers have produced a toolkit designed to recognize those evolutionary changes, with the snakes, that have been caused through the Darwinian process of natural selection. Part of the research process was to determine the variants of genes that give rise to unique traits. The work is also interesting for the process, signaling that biologists need to work with computer programmers in order to make sense of the vast amount of genetic data relating to each species.
Burmese python (Python molurus bivittatus)
Burmese python (Python molurus bivittatus)
The research team was led by Professor Todd Castoe and he set the following research questions in relation to the snakes: and the genetic information he planned to unlock:
How did they develop venom?
How do they regenerate their organs?
How do evolutionarily-derived variations in genes lead to variations in how organisms look and function?
As the academic explains, in a research note: "Some of the most basic questions drive our research. Yet trying to understand the genetic explanations of such questions is surprisingly difficult considering most vertebrate genomes, including our own, are made up of literally billions of DNA bases that can determine how an organism looks and functions.”
He adds: "Understanding these links between differences in DNA and differences in form and function is central to understanding biology and disease, and investigating these critical links requires massive computing power."
Physics simulation of 5 megabases of DNA forming loops and domains.
Physics simulation of 5 megabases of DNA forming loops and domains.
Courtesy of Adrian Sanborn, Erez Lieberman Aiden
Central to the analysis of the snake genomes were the supercomputing and data analysis resources at the Texas Advanced Computing Center. This data driven approach revealed a number of areas of interest. First it was found that Burmese pythons down-regulate their metabolic and physiological functions during periods of fasting. As this happens the organs atrophy, which is a process designed to save energy. Once the snake begins feeding again, the size and function of their organs increase considerably to accommodate digestion. Such is the growth that within 48 hours of feeding, pythons undergo a 44-fold increase in metabolic rate. Here the mass of their major organs increases between 40 to 100 percent.
What interested the biologist was that very few sets of genes influenced the wholesale change of pythons' internal organ structure. It was found that certain proteins, produced and regulated by these important genes, activated a cascade of diverse, tissue-specific signals. These led to regenerative organ growth.
A young woma python. Notice the beautiful markings.
A young woma python. Notice the beautiful markings.
HLH Reptiles
This phenomenal rate of growth has been reported to the journal BMC Genomics, in a paper titled “Growth and stress response mechanisms underlying post-feeding regenerative organ growth in the Burmese python.”
Of longer term interest is with the signaling function. If this is conserved across species could it one day be used to improve human health?
A second area of research looked at two species of rattlesnake found on opposite sides of the Continental Divide in Mexico and the U.S. The research focus was to explore which forces generate and maintain distinct species, and particularly how shifts in the ranges of species impact upon species and speciation. This required an analysis of thousands of genes in the rattlesnakes' nuclear DNA. The study showed a relationship between the genetic traits that are most important in evolution during isolation as Well as those traits that are most important during secondary contact.
The follow up research has been published in the journal Ecology and Evolution. This paper is titled “GppFst genomic posterior predictive simulations of F ST and d XY for identifying outlier loci from population genomic da.”
Essential Science
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When it's young, a red dwarf star frequently erupts with strong ultraviolet flares as shown in this artist's conception. Some have argued that life would be impossible on any planet orbiting in the star's habitable zone as a result. However, the planet's atmosphere could protect the surface, and in fact such stresses could help life to evolve. And when the star ages and settles down, its planet would enjoy billions of years of quiet, steady radiance.
This article is part of Digital Journal's regular Essential Science columns. Each week Tim Sandle explores a topical and important scientific issue. Last week we looked at where life might occur in the universe, focusing on exoplanets around red dwarf stars. The week before we looked at how the microorganisms found in hospitals alter over time and the explored the routes by which patients might become infected.