HOME >> BIOLOGY >> NEWS
Scientists uncover new clues to limb formation (and loss) in some sea mammals

Researchers from the Northeastern Ohio Universities College of Medicine have revealed the genetic basis behind one of the best-documented examples of evolutionary change in the fossil record: how whales lost their hind limbs.

Writing in this week's Proceedings of the National Academy of Sciences (PNAS), Hans Thewissen and his colleagues report that ancient whales--four-footed land animals not unlike large modern dogs--evolved into graceful, streamlined swimmers through a series of small genetic changes during the whales' embryonic development.

"Their research has implications for how evolution acts to create dramatic changes in an organism's body," said Richard Lane, program director in the National Science Foundation (NSF)'s Division of Earth Sciences, which funded the research.

"The findings emphasize the synergistic role traditional paleontology and evolutionary and developmental biology play at the frontiers of the evolutionary sciences," said Lane.

Thewissen and his colleagues began by exploring the embryonic development of whales' cousins, the dolphins. These creatures are intriguing because for a brief time during development they do sprout hind limbs, which quickly vanish again as the embryos reach the second month in a gestation period that lasts about 12 months.

Why? In most mammals, explains Thewissen, "a series of genes is at work at different times, delicately interacting to form a limb with muscles, bones, and skin. The genes are similar to the runners in a complex relay race, where a new runner cannot start without receiving a sign from a previous runner."

In dolphins, however, at least one of the genes drops out early in the race, disrupting the genes that were about to follow it. That causes the entire relay to collapse, ultimately leading to the regression of the animals' hind limbs. By analyzing dolphin embryos, Thewissen showed that the dropout is a gene called "Sonic Hedgehog," which is important
'"/>

Contact: Cheryl Dybas
cdybas@nsf.gov
703-292-7734
National Science Foundation
22-May-2006


Page: 1 2

Related biology news :

1. Scientists show that mitochondrial DNA variants are linked to risk factors for type 2 diabetes
2. Scientists prove that disputed Korean stem cell line comes from an unfertilized egg and not cloning
3. Scientists move closer to bio-engineered bladders
4. Scientists find stem cell switch
5. Scientists discover new way to study nanostructures
6. Scientists a step closer to understanding how anaesthetics work in the brain
7. Scientists to make news at Computational Biology Conference
8. Accident-prone? Scientists link brain function to knee injuries
9. Scientists take next step in understanding potential target for ovarian cancer treatment
10. Scientists find brown fat master switch
11. Scientists identify 2 distinct Parkinsons networks

Post Your Comments:
*Name:
*Comment:
*Email:
TAG: Scientists uncover new clues limb formation and loss some sea mammals

(Date:10/17/2014)... Copenhagen have shown for the first time how bacteria ... patients, giving them the opportunity to get tremendous insights ... The study also discovered the bacterial growth in chronic ... or slowed down by the immune cells. The researchers ... helped "suffocate" the bacteria, forcing the bacteria to switch ...
(Date:10/16/2014)... human body. Battles are won, lost or sometimes ... stalemate—known as tumor dormancy—can last up to 25 ... is poorly understood. , A new computational ... a Professor of Chemistry at Princeton University, may ... the switch to a malignant state. Published today ...
(Date:10/16/2014)... Oregon and Washington land managers have a new synthesis ... eastside moist mixed-conifer (MMC) forests in the two states. ... Forests in Eastern Oregon and Washington: A Synthesis of ... Management, a general technical report published by the U.S. ... response to a request from managers for a synthesis ...
Breaking Biology News(10 mins):Scientists opens black box on bacterial growth in cystic fibrosis lung infection 2Modeling tumor dormancy 2New report synthesizes best available science on management of moist mixed-conifer forests 2
(Date:10/19/2014)... 2014 OCTOBER 20-22, 2014: ... ABIM will take place at the ... ABIM 2014 is now available at ... companies and organizations from all over the ... on the latest products and developments on ...
(Date:10/19/2014)... October 19, 2014 The Asia-Pacific Speech ... market in Asia-Pacific with analysis and forecast of revenue. ... in 2014 to $208 million by 2019, at a ... to 2019. , Browse through the TOC of the ... of the in-depth analysis provided. It also provides a ...
(Date:10/19/2014)... 19, 2014 According to market ... Points; WLAN Controllers; Wireless gateways)]- Global Advancements, Forecasts ... the global Outdoor Wi-Fi market with analysis and ... MarketsandMarkets also identifies the drivers and the restrains ... trends, opportunities and challenges. , Browse 65 market ...
(Date:10/18/2014)... The Asian arthroscopic devices report defines and ... forecast of revenue. The arthroscopic devices market in Asia ... at a CAGR of 6.5% from 2013 to 2018. ... devices market, to get an idea of the in-depth ... segmentation of arthroscopic devices market in the same region, ...
Breaking Biology Technology:The Asia-Pacific Speech Analytics market is estimated to reach $208 million by 2019 - New Report by MicroMarket Monitor 2The Asia-Pacific Speech Analytics market is estimated to reach $208 million by 2019 - New Report by MicroMarket Monitor 3The Asia-Pacific Speech Analytics market is estimated to reach $208 million by 2019 - New Report by MicroMarket Monitor 4Outdoor Wi-Fi Market (by Access Points, WLAN Controllers, Wireless gateways) Expected to Cross $37.2 Billion by 2018 - New Report by MarketsandMarkets 2Outdoor Wi-Fi Market (by Access Points, WLAN Controllers, Wireless gateways) Expected to Cross $37.2 Billion by 2018 - New Report by MarketsandMarkets 3Outdoor Wi-Fi Market (by Access Points, WLAN Controllers, Wireless gateways) Expected to Cross $37.2 Billion by 2018 - New Report by MarketsandMarkets 4The Asian arthroscopic devices market is estimated to grow to $712.3 million by 2018 - New Report by MicroMarket Monitor 2The Asian arthroscopic devices market is estimated to grow to $712.3 million by 2018 - New Report by MicroMarket Monitor 3The Asian arthroscopic devices market is estimated to grow to $712.3 million by 2018 - New Report by MicroMarket Monitor 4
Cached News: