Navigation Links
Many a mickle makes a muckle: How changes in animals' size and shape arise
Date:6/30/2011

The transcription of genes is tightly controlled, with a bewildering array of regulatory DNA sequences interacting with a similarly large number of proteins and other factors to determine which genes are active when and where. Understanding how it all works has challenged countless molecular biologists over the past decades but we are now starting to make significant progress. Even so, we have scarcely begun to understand how the entire complexity evolves to give differences in the size and shape of organisms. Exciting new findings are now reported by the group of David Stern at Princeton University, in collaboration with Alistair McGregor of the University of Veterinary Medicine, Vienna and with Franois Payre of the Universit de Toulouse.

Stern's group is investigating the evolution of morphology in fruit flies. The larvae of two closely related flies, the widespread Drosophila melanogaster (which appear as if by magic around our fruit bowls in summer) and the more local Drosophila sechellia (which is found only on the Seychelles), differ in their patterns of hairs or "trichomes". The difference stems from changes in the expression of the wonderfully named "shaven baby" (svb) gene: svb is not expressed in certain types of cells in Drosophila sechellia and as a result their larvae lack lawns of hairs on the tops and sides of their backs.

Previous work in Stern's group had determined that differences in the DNA sequence of the svb regulatory region caused the difference between the hairy and naked species. McGregor found that particular regions of the so-called enhancer E were responsible for controlling expression of the svb gene on the top and sides of fly larvae. The sequence of E6, the part of the enhancer that activates the gene, is subtly different in Drosophila sechellia compared with other related species and two post-docs in Stern's lab, Nicols Frankel and Deniz F. Erezyilmaz, have now systematically examined the effects of each of the changes in isolation and together.

The results provide an elegant demonstration of evolution in action. At least five changes were found to contribute to the altered functional properties of the enhancer. Interestingly, none of the changes on its own has a particularly dramatic effect and the effect of all the changes together is far greater than the sums of all the individual effects. In other words, the effect of any particular change depends on what changes may already be present.

As McGregor notes, the experiments reported in the current issue of Nature represent "one of the first functional dissections of the contribution of individual nucleotide changes in an enhancer responsible for morphological evolution." The results provide a possible explanation for how individual mutations, each with relatively minor consequences, can be "fixed" in a population as a result of subsequent events, leading ultimately to the evolution of distinct morphologies.

McGregor has now left Vienna for Oxford Brookes University (UK), where he is continuing his study of the evolution of animal development and morphology.


'/>"/>

Contact: Dr. Alastair McGregor
amcgregor@brookes.ac.uk
44-784-037-2939
University of Veterinary Medicine -- Vienna
Source:Eurekalert

Related medicine news :

1. Heightened immunity to colds makes asthma flare-ups worse, U-M research shows
2. Note to dads: Good parenting makes a difference
3. Cancer Drug Avastin Makes Inroads Against Ovarian Tumors
4. U.S. Makes It Easier to Get Insurance With Pre-Existing Conditions
5. MIT research: What makes an image memorable?
6. Leopoldina makes recommendations to the G8 heads of state and government
7. ESC Policy Conference makes recommendations for new EU medical device legislation
8. Mayo Clinic studies how much practice makes perfect when performing colonoscopies
9. What Makes a Face Appealing to the Opposite Sex?
10. Why Someone Elses Gaffe Makes You Cringe
11. Cost of heart drugs makes patients skip pills, putting themselves at risk
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:10/13/2017)... ... 13, 2017 , ... The Visiting Nurse Association (VNA) of Somerset Hills is ... vendors and unique items from across the nation, this holiday-themed event will raise funds ... by the VNA. The boutique will be open Saturday, November 4 (10:00 a.m. ...
(Date:10/13/2017)... ... 2017 , ... Global Healthcare Management’s 4th Annual Kids Fun Run brought out ... free event, sponsored by Global Healthcare Management’s CEO, Jon Letko, is aimed at getting ... children of all ages; it is a non-competitive, non-timed event, which is all about ...
(Date:10/13/2017)... ... October 13, 2017 , ... ... viewers the lowdown on sciatica in a new episode of "Success Files," which ... current events and innovation and investigates each subject in-depth with passion and integrity. ...
(Date:10/13/2017)... ... ... Journey: From the Mountains to the Mission Field”: the story of a missionary couple ... From the Mountains to the Mission Field” is the creation of published author, Carole ... and currently teaches a class of ladies at her church, which she has taught ...
(Date:10/12/2017)... ... October 12, 2017 , ... First Healthcare Compliance ... management, will showcase a range of technology and learning solutions at the 68th ... and Expo to be held October 14–18, 2017 at the Mandalay Bay Resort ...
Breaking Medicine News(10 mins):
(Date:9/27/2017)...  Commended for their devotion to personalized service, SMP Pharmacy ... one in the South Florida Business Journal,s 50 Fastest-Growing Companies, ... list, the national specialty pharmacy has found its niche.  To ... soon be honored by SFBJ as the 2017 Power Leader ... to receive his award in October, Bardisa said of the ...
(Date:9/23/2017)... Pa. , Sept. 22, 2017 Janssen ... a complete response letter from the U.S. Food and ... seeking approval of sirukumab for the treatment of moderately ... letter indicates additional clinical data are needed to further ... moderately to severely active RA. ...
(Date:9/19/2017)... 19, 2017   ZirMed Inc ., a recognized leader ... that it has been ranked #1 by its users for ... Rankings 2017 User Survey. ZirMed was recognized as the top-ranked ... and medical centers over 200 beds and holds one of ... user survey history. ...
Breaking Medicine Technology: