Corporate Banner
Satellite Banner
Scientific Communities
Become a Member | Sign in
Home>News>This Article

Two Mutations Triggered an Evolutionary Leap 500 Million Years Ago

Published: Wednesday, June 26, 2013
Last Updated: Wednesday, June 26, 2013
Bookmark and Share
Researchers discover just two mutations set the stage for the evolution of modern hormone signaling.

A research team led by a University of Chicago scientist has discovered two key mutations that sparked a hormonal revolution 500 million years ago.

In a feat of "molecular time travel," the researchers resurrected and analyzed the functions of the ancestors of genes that play key roles in modern human reproduction, development, immunity and cancer. By re-creating the same DNA changes that occurred during those genes' ancient history, the team showed that two mutations set the stage for hormones like estrogen, testosterone and cortisol to take on their crucial present-day roles.

"Changes in just two letters of the genetic code in our deep evolutionary past caused a massive shift in the function of one protein and set in motion the evolution of our present-day hormonal and reproductive systems," said Joe Thornton, PhD, professor of human genetics and ecology & evolution at the University of Chicago, who led the study.

"If those two mutations had not happened, our bodies today would have to use different mechanisms to regulate pregnancy, libido, the response to stress, kidney function, inflammation, and the development of male and female characteristics at puberty," Thornton said.

The findings were published online June 24 in the Proceedings of the National Academy of Sciences.

Understanding how the genetic code of a protein determines its functions would allow biochemists to better design drugs and predict the effects of mutations on disease. Thornton said the discovery shows how evolutionary analysis of proteins' histories can advance this goal. Before the group's work, it was not previously known how the various steroid receptors in modern species distinguish estrogens from other hormones.

The team, which included researchers from the University of Oregon, Emory University and the Scripps Research Institute, studied the evolution of a family of proteins called steroid hormone receptors, which mediate the effects of hormones on reproduction, development and physiology. Without receptor proteins, these hormones cannot affect the body's cells.

Thornton's group traced how the ancestor of the entire receptor family -- which recognized only estrogens -- evolved into descendant proteins capable of recognizing other steroid hormones, such as testosterone, progesterone and the stress hormone cortisol.

Molecular Resurrection

To do so, the group used a gene "resurrection" strategy. They first inferred the genetic sequences of ancient receptor proteins, using computational methods to work their way back up the tree of life from a database of hundreds of present-day receptor sequences. They then biochemically synthesized these ancient DNA sequences and used molecular assays to determine the receptors' sensitivity to various hormones.

Thornton's team narrowed down the time range during which the capacity to recognize non-estrogen steroids evolved, to a period about 500 million years ago, before the dawn of vertebrate animals on Earth. They then identified the most important mutations that occurred during that interval by introducing them into the reconstructed ancestral proteins. By measuring how the mutations affected the receptor's structure and function, the team could re-create ancient molecular evolution in the laboratory.

They found that just two changes in the ancient receptor's gene sequence caused a 70,000-fold shift in preference away from estrogens toward other steroid hormones. The researchers also used biophysical techniques to identify the precise atomic-level mechanisms by which the mutations affected the protein's functions. Although only a few atoms in the protein were changed, this radically rewired the network of interactions between the receptor and the hormone, leading to a massive change in function.

"Our findings show that new molecular functions can evolve by sudden large leaps due to a few tiny changes in the genetic code," Thornton said. He pointed out that, along with the two key changes in the receptor, additional mutations, the precise effects of which are not yet known, were necessary for the full effects of hormone signaling on the body to evolve.

Further Information
Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 2,600+ scientific posters on ePosters
  • More Than 3,800+ scientific videos on LabTube
  • 35 community eNewsletters

Sign In

Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Related Content

Long Telomeres Associated with Increased Lung Cancer Risk
Genetic predisposition for long telomeres predicts increased lung adenocarcinoma risk.
Friday, July 31, 2015
University of Chicago to Establish Genomic Data Commons
First-of-its-kind facility expands access to large-scale cancer genomic data.
Wednesday, December 03, 2014
Childhood Asthma Tied to Combination of Genes and Wheezing Illness
Interaction between gene and environment predicts disease onset.
Thursday, March 28, 2013
New Technique Reveals Unseen Information in DNA Code
Scientists have developed and tested a technique to distinguish between two modified forms of cytosine.
Friday, May 18, 2012
Scientific News
Fixing Holes in the Heart Without Invasive Surgery
UV-light enabled catheter is a medical device which represents a major shift in how cardiac defects are repaired.
Chromosomal Chaos
Penn study forms basis for future precision medicine approaches for Sezary syndrome
Enzyme Malfunction May be Why Binge Drinking Can Lead to Alcoholism
A new study in mice shows that restoring the synthesis of a key brain chemical tied to inhibiting addictive behavior may help prevent alcohol cravings following binge drinking.
Key to Natural Detoxifier’s Reactivity Discovered
Results have implications for health, drug design and chemical synthesis.
New Treatment for Obesity Developed
Researchers at the University of Liverpool, working with a global healthcare company, have helped develop a new treatment for obesity.
New Protein Found in Immune Cells
Immunobiologists from the University of Freiburg discover Kidins220/ARMS in B cells and demonstrate its functions.
Will Brain Palpation Soon Be Possible?
Researchers have developed non-invasive brain imaging technique which provides the same information as physical palpation.
Shaking Up the Foundations of Epigenetics
Researchers at the Centre for Genomic Regulation (CRG) and the University of Barcelona (UB) published a study that challenges some of the current beliefs about epigenetics.
Groundbreaking Computer Program Diagnoses Cancer in Two Days
Researchers have combined genetics with computer science and created a new diagnostic technology can with 85 per cent certainty identify the source of the disease and thus target treatment and, ultimately, improve the prognosis for the patient.
Michigan Researchers Use Raman Spectroscopy
inVia confocal Raman microscope used in the study of various childhood diseases.
Scroll Up
Scroll Down
Skyscraper Banner

Skyscraper Banner
Go to LabTube
Go to eposters
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
2,600+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
3,800+ scientific videos