HOME >> BIOLOGY >> NEWS
How ancient whales lost their legs, got sleek and conquered the oceans

When ancient whales finally parted company with the last remnants of their legs about 35 million years ago, a relatively sudden genetic event may have crowned an eons-long shrinking process.

An international group of scientists led by Hans Thewissen, Ph.D., a professor of anatomy at Northeastern Ohio Universities College of Medicine, has used developmental data from contemporary spotted dolphins and fossils of ancient whales to try to pinpoint the genetic changes that could have caused whales, dolphins and porpoises to lose their hind limbs.

More than 50 million years ago the ancestors of whales and dolphins were four-footed land animals, not unlike large dogs. They became the sleek swimmers we recognize today during the next 15 million years, losing their hind limbs in a dramatic example of evolutionary change.

"We can see from fossils that whales clearly lived on land - they actually share a common ancestor with hippos, camels and deer," said team member Martin Cohn, Ph.D., a developmental biologist and associate professor with the UF departments of zoology and anatomy and cell biology and a member of the UF Genetics Institute. "Their transition to an aquatic lifestyle occurred long before they eliminated their hind limbs. During the transition, their limbs became smaller, but they kept the same number and arrangement of hind limb bones as their terrestrial ancestors."

In findings to be published this week in the Proceedings of the National Academy of Sciences, scientists say the gradual shrinkage of the whales' hind limbs over 15 million years was the result of slowly accumulated genetic changes that influenced the size of the limbs and that these changes happened sometime late in development, during the fetal period.

However, the actual loss of the hind limb occurred much further along in the evolutionary process, when a drastic change occurred to inactivate a gene essential for limb development. This gene - called Sonic h
'"/>

Contact: John D. Pastor
jpastor@vpha.health.ufl.edu
352-273-5815
University of Florida
22-May-2006


Page: 1 2 3

Related biology news :

1. Immunity in social amoeba suggests ancient beginnings
2. Greenlands ancient forests shed light on stability of ice sheet
3. Modern brains have an ancient core
4. Caribbean frog populations started with single, ancient voyage on South American raft
5. Caribbean frogs started with a single, ancient voyage on a raft from South America
6. An ancient bathtub ring of mammoth fossils
7. Volcanic eruptions, ancient global warming linked
8. Fossil discovery marks earliest record of limbloss in ancient lizard
9. Smithsonian scientists report ancient chili pepper history
10. Global warming of the future is projected by ancient carbon emissions
11. UCSD scientists establish connection between life today and ancient changes in ocean chemistry

Post Your Comments:
*Name:
*Comment:
*Email:


(Date:3/3/2020)... ... March 03, 2020 , ... Amplify Surgical, Inc., today announces that ... Interbody Fusion System. , The landmark case was performed by Dr. Ali ... Dr. Najafi noted, “dualX has completely changed the game for expandable interbodies. The ...
(Date:3/2/2020)... ... ... Toronto-based clinical research organization (CRO) and regulatory consulting firm, dicentra , has announced ... Clarksburg on a farm on Beaver Valley Road. , The owners currently operate an ... it would be a great new option for employees to relocate to. , “Part ...
(Date:3/2/2020)... ... March 02, 2020 , ... Nominations are now being accepted ... the Security Industry Association (SIA) and SecureIDNews and co-presented with ... Security Forum . The recipients of this year’s Women in Biometrics Awards will be ...
Breaking Biology News(10 mins):
(Date:3/27/2020)... ... ... iFirst Medical Technologies, Inc., a leader in handheld diagnostic devices, announced today that it ... danger to public health here in the U.S. and around the globe," said Luke ... on-the-spot results promise to slow the spread and save human lives." , iFirst has ...
(Date:3/10/2020)... ... ... Ortho Clinical Diagnostics, a global leader of in vitro diagnostics dedicated to improving ... of extended antigen in a gel testing format used for blood phenotyping for patients ... Max in the United States and Canada. The clearances allow testing for more than ...
(Date:3/3/2020)... ... 03, 2020 , ... Frictionless Solutions, a specialized event services ... recognized by INC. 5,000 on an annual list of America’s fastest growing private ... impacting their spheres of influence and experiencing considerable development. INC. 5,000’s specific list ...
(Date:2/21/2020)... ... 20, 2020 , ... In a free session on Tuesday, March ... including Lisa Dilworth, BS, MS, Vice President Rare, Orphan and Pediatric Diseases, and Rachael ... solutions to support patients, sites and sponsors. , When planning a rare disease clinical ...
Breaking Biology Technology:
Cached News: