Subscribe free to our newsletters via your
. Earth Science News .


Subscribe free to our newsletters via your




















FLORA AND FAUNA
What twisting snails can tell us about animals' intriguing asymmetries
by Staff Writers
Washington DC (SPX) Feb 29, 2016


This is a photograph of the grove snail (Cepaea nemoralis) twisting around a plant stem. Image courtesy Lauren Holden. For a larger version of this image please go here.

While people and many animals might look pretty symmetrical on the outside, inside our bodies we are all fundamentally asymmetric. For example, the human heart is found to the left of center. Snails are similarly asymmetric in their appearance, and more obviously so: the shells and bodies of some snails twist around to the right, whereas others twist to the left.

Now researchers reporting in the Cell Press journal Current Biology on February 25 have an idea how it works. And, surprisingly enough, it turns out that the gene responsible for the variably asymmetrical bodies of some snail species also plays a role in defining the internal asymmetries in frogs.

The findings reveal that asymmetry is an evolutionarily ancient characteristic of animal body plans, the researchers say.

"Animals tend to be outwardly symmetric in appearance but are almost all asymmetrical inside," says Angus Davison of The University of Nottingham. "It hasn't been clear if asymmetry is an ancient feature or something that has evolved several times. By identifying an evolutionarily conserved protein that controls asymmetry in both snails and frogs, we have shown that body asymmetry in most animals, including humans, likely arises from a highly conserved, intrinsic asymmetry of the cells in the early embryo."

Davison says he first got intrigued with snail shell coiling when he was living in Japan in 2001 and he noticed that the snails around him were twisting in what he considered to be the "wrong" direction. Ever since then, he has wanted to find the gene responsible for this switch.

In the new study, he and his colleagues sequenced the genome of a pond snail species that shows variation in the coiling direction of its shells. They then used genetic mapping techniques to narrow the list of potential gene candidates down to six.

They knew they'd found what they were looking for when they landed a mutation in one gene that rendered it inactive in the anti-clockwise coiling form of the snail. That mutation appeared in a gene called formin.

The researchers went on to show that this gene is active in just the right place in early embryos. They also found that an anti-formin drug treatment delivered to developing snails could partially convert clockwise twisting snails to mirror-image snails that twist the other way. Ultimately, those snails didn't survive, but the findings showed that formin worked in the way they suspected.

"We were surprised to find that asymmetry is present in the very early embryo, from the two-cell stage onwards," says Dan Jackson of the University of Gottingen, Germany.

Those findings in snails led them to wonder whether the same gene has a similar function in specifying left-right asymmetry in developing frog embryos. And, it turns out, it does.

The new evidence leads the researchers to suggest that formin is among the earliest "symmetry-breaking" molecular components across all animals with bilateral symmetry, meaning animals with bodies that have an obvious left and right side. (Bilateral symmetry is in contrast to radial symmetry, found in jellyfish and sponges, for example.)

"This work supports a unified evolutionary view by showing that even vertebrates initiate asymmetry very early in development using the same intracellular toolkit as invertebrates," Davison says.

He says they now hope to further explore the intricacies of the symmetry-breaking switch in pond snails. They'll also examine other snails that exist in mirror-image forms in nature in search of more asymmetry genes.

Current Biology, Davison et al.: "Formin Is Associated with Left-Right Asymmetry in the Pond Snail and the Frog"

.


Related Links
Cell Press
Darwin Today At TerraDaily.com






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
FLORA AND FAUNA
Humans speeding up evolution by causing extinction of 'younger' species
Vancouver, Canada (SPX) Feb 25, 2016
Just three years after crayfish were introduced to a B.C. lake, two species of fish that had existed in the lake for thousands of years were suddenly extinct. But it's what took their place that has scientists fascinated. New research from UBC shows that when humans speed up the usually slow process of evolution by introducing new species, it can result in a lasting impact on the ecosystem ... read more


FLORA AND FAUNA
Brazil police charge seven in Samarco mine deaths: reports

MH370 lawsuits gain pace as two-year deadline nears

Aid finally getting to Fiji cyclone victims

Nuclear water: Fukushima still faces contamination crisis

FLORA AND FAUNA
New research introduces 'pause button' for boiling

Real or virtual - can we tell the difference

Breakthrough in dynamically variable negative stiffness structures

Eco-friendly food packaging material doubles shelf-life of food products

FLORA AND FAUNA
Sea-level rise past and future: Robust estimates for coastal planners

Climate change speeds up gully erosion

Researchers sequence seagrass genome, unlocking valuable resource

Herring fishery's strength is in the sum of its parts, study finds

FLORA AND FAUNA
OGC requests information to guide Arctic Spatial Data Pilot

Australian icebreaker runs aground in Antarctica

Study of tundra soil demonstrates vulnerability of ecosystem to climate warming

Ice age blob of warm ocean water discovered south of Greenland

FLORA AND FAUNA
New wheat genetic advancements aimed at yield enhancement

China's Jack Ma buys French vineyard

PM tells drought-stricken Thailand to cut rice production

Scientists draw first European earthworm map

FLORA AND FAUNA
Fiji eyes more cyclone aid as toll hits 44

Fiji cyclone death toll rises to 42: official

Cyclone death toll hits 29 as Fiji eyes long clean-up

Christchurch commemorates devastating quake

FLORA AND FAUNA
Voice of China: Beijing seeks African friends and influence

Kenya army says it killed Shebab intelligence chief

Three soldiers get life for I.Coast military chief's murder

Saving the wildlife 'miracle' of Congo's Garamba park

FLORA AND FAUNA
Easter Island not destroyed by war, analysis of 'spear points' shows

Neanderthals and modern H. sapiens crossbred over 100,000 years ago

Neanderthals mated with modern humans much earlier than previously thought

Modern 'Indiana Jones' on mission to save antiquities




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News








The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.