Nav: Home

Life in Antarctica's ice mirrors human disease

June 10, 2019

The cooling of the Southern Ocean surrounding Antarctica, which began approximately 35 million years ago and gave rise to its present icy state, has for decades been considered a classic example of climate change triggering rapid adaptation.

Using tens of thousands of genes mapped from across the genomes of a group of Antarctic fishes called notothenioids, a team of researchers is now challenging this paradigm, revealing that the massive amount of genetic change required for life in the Antarctic occurred long before the Antarctic cooled.

These genetic changes not only have major implications for understanding the evolution of Antarctica's unusual animals, but also highlight that some key adaptations used by fishes mirror the genetics of human bone diseases such as osteoporosis.

"Many species have evolved traits that are adaptive in their environment but are similar to disease states in humans," says Jake Daane, lead author of the study (Northeastern University). "We use this natural variation to better understand genetic mechanisms of disease."

The team found evidence of an increase in mutation rate during the evolution of Antarctic fishes prior to the onset of icy waters in the Southern Ocean that corresponded with a severe reduction of bone mineral density.

"Antarctic notothenioids don't have swim bladders to adjust their buoyancy in the water column. Rather, they use reductions in bone density to help them 'float' in the water column at low energetic cost," says co-author Bill Detrich (coauthor, Northeastern University). "What is a genetic disease state in us is a means of survival in these fishes."

"The genetic changes we found are severely pathological in humans, including some that have been considered not compatible with life," added Alex Dornburg (coauthor, North Carolina Museum of Natural Sciences). "Finding that notothenioids use the same genetic pathways to achieve buoyancy in water represents a tremendous opportunity for human health research."

To test the function of the genetic changes identified, the team further used advances in gene editing to engineer genetically modified zebrafish embryos with the same mutations as Antarctic notothenioids. As these zebrafish grew, they displayed the same loss of bone as observed in the Antarctic species.

"Our research is revealing Antarctic notothenioids to be important models for human disease. In addition to low bone density, Antarctic fishes also have evolved other apparently pathological conditions, including the loss of kidney glomeruli and red blood cells," says Matthew Harris (coauthor, Boston Children's Hospital and Harvard Medical School).

Harris added, "These biomedically-relevant processes can be studied to reveal the genetic mechanisms behind these 'disease' states and their accommodation in these fishes. The results should lead to deeper understanding of how we might treat comparable disorders in humans."

Rather than evolving these unusual adaptations in the face of major environmental upheaval, the team found that much of this genetic variation was already in place before the Antarctic cooled. This finding challenges how we consider adaptation versus standing genetic diversity to predict the response of modern populations to contemporary climate change.

Antarctic notothenioids were in the right place at the right time to capitalize on the transition to an icy Antarctic millions of years ago. However, their future is uncertain.

"Notothenioids are of high ecological, economic and medical importance, however, many species can't tolerate warming of more than a few degrees," says Thomas Near (coauthor, Yale University). "In an ironic twist of fate, forecasts of climate change now warn that this unique radiation of fishes could become decimated over the next century. It is up to us to prevent such a tragic loss."
-end-
The paper, "Historical contingency shapes adaptive radiation in Antarctic fishes," was posted as an Advance Online Publication on Nature Ecology & Evolution's website 10 June 2019, and appears here: https://www.nature.com/articles/s41559-019-0914-2.

North Carolina Museum of Natural Sciences

Related Climate Change Articles:

The black forest and climate change
Silver and Douglas firs could replace Norway spruce in the long run due to their greater resistance to droughts.
For some US counties, climate change will be particularly costly
A highly granular assessment of the impacts of climate change on the US economy suggests that each 1°Celsius increase in temperature will cost 1.2 percent of the country's gross domestic product, on average.
Climate change label leads to climate science acceptance
A new Cornell University study finds that labels matter when it comes to acceptance of climate science.
Was that climate change?
A new four-step 'framework' aims to test the contribution of climate change to record-setting extreme weather events.
It's more than just climate change
Accurately modeling climate change and interactive human factors -- including inequality, consumption, and population -- is essential for the effective science-based policies and measures needed to benefit and sustain current and future generations.
Climate change scientists should think more about sex
Climate change can have a different impact on male and female fish, shellfish and other marine animals, with widespread implications for the future of marine life and the production of seafood.
Climate change prompts Alaska fish to change breeding behavior
A new University of Washington study finds that one of Alaska's most abundant freshwater fish species is altering its breeding patterns in response to climate change, which could impact the ecology of northern lakes that already acutely feel the effects of a changing climate.
Uncertainties related to climate engineering limit its use in curbing climate change
Climate engineering refers to the systematic, large-scale modification of the environment using various climate intervention techniques.
Public holds polarized views about climate change and trust in climate scientists
There are gaping divisions in Americans' views across every dimension of the climate debate, including causes and cures for climate change and trust in climate scientists and their research, according to a new Pew Research Center survey.
The psychology behind climate change denial
In a new thesis in psychology, Kirsti Jylhä at Uppsala University has studied the psychology behind climate change denial.

Related Climate Change Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#SB2 2019 Science Birthday Minisode: Mary Golda Ross
Our second annual Science Birthday is here, and this year we celebrate the wonderful Mary Golda Ross, born 9 August 1908. She died in 2008 at age 99, but left a lasting mark on the science of rocketry and space exploration as an early woman in engineering, and one of the first Native Americans in engineering. Join Rachelle and Bethany for this very special birthday minisode celebrating Mary and her achievements. Thanks to our Patreons who make this show possible! Read more about Mary G. Ross: Interview with Mary Ross on Lash Publications International, by Laurel Sheppard Meet Mary Golda...