Animals have an astonishing ability to develop reliably, in spite of variable conditions during embryogenesis. New research published this week addresses how living things can develop into precise, adult forms when there is so much variation present during their development stages. A team led by John Reinitz at Stony Brook University, and funded by the National Institutes of Health, shows how fruit fly embryos can "forget" initial incorrect versions of their body plan and develop into recognizable adult flies.
Canalization, a principle of developmental biology described more than 60 years ago by C.H. Waddington, is the property of embryonic development whereby genetic interactions can adjust biochemical reactions to bring about reliable developmental outcomes, despite variable conditions.
A great deal of progress has been made in understanding the buffering of genotypic and environmental variation, and individual mutations that reveal variation have been identified. However, the mechanisms by which genetic interactions produce canalization are not yet well understood, because this requires molecular data on multiple developmental determinants and models that correctly predict complex interactions.
"We make use of gene expression data at both high spatial and temporal resolution for the gap genes involved in the segmentation of the fruit fly Drosophila embryo," said Reinitz. "We also apply a mathematical model to show that cross regulation among the gap genes is responsible for canalization in this system."
The model predicted specific interactions that cause canalization, and the prediction was validated in experiments.
"With canalization, if there is too much of one protein in the embryo, a network of genes could theoretically change the amount of that protein present, so that the outcome for the embryo was normal," said Reinitz. "Since this principle was suggested, a great deal of progress has been made in understanding the buffering of variation, but the specific mechanisms by which genetic interactions contribute to canalization have remained unclear – until now."
The authors started by measuring the concentrations of certain proteins in normal and mutant Drosophila embryos, at an early stage of development when the embryo looks like a hollow rugby ball. Each protein is synthesized from a gene, and each of the proteins measured has a regulatory role; they can turn their own gene - and others - on and off. The authors created a series of equations that could describe the diffusion of proteins and their action on their own gene and on other genes in the network. These equations show that a wide range of initial conditions (in terms of protein concentrations) lead to several possible final conditions.
These final conditions, called fixed points, govern or describe the final state of the segmentation process for the fruit fly embryo. They do not allow for variability in the embryo, and they 'forget' the initial information. This mathematical property combined with their accuracy in describing the biological processes can be used towards the theoretical explanation for Waddington's canalization model.
"This study is an example of how biology is becoming a precise and quantitative field, like physics," says Reinitz.
Citation: Manu, Surkova S, Spirov AV, Gursky V V, Janssens H, et al. (2009) Canalization of gene expression in the Drosophila blastoderm by gap gene cross regulation. PLoS Biol 7(3): e1000049. doi:10.1371/journal.pbio.1000049
Citation: Manu, Surkova S, Spirov AV, Gursky VV, Janssens H, et al. (2009) Canalization of Gene Expression and Domain Shifts in the Drosophila Blastoderm by Dynamical Attractors. PLoS Comput Biol 5(3): e1000303. doi:10.1371/journal.pcbi.1000303
- PHYSICAL SCIENCES
- EARTH SCIENCES
- LIFE SCIENCES
- SOCIAL SCIENCES
Subscribe to the newsletter
Stay in touch with the scientific world!
Know Science And Want To Write?
- Wait, Let's Not Be In Such A Rush To Go Multiplanetary Or Interstellar - A Comment On Elon Musk's Vision
- Petition To Youtube To Halt Ads On Doomsday Videos - They Make The Vulnerable Suicidal
- Paleo: In A Clinical Trial, Bread Made With Ancient Grains Could Benefit Heart Health
- Hubble Spots Europa Geysers Again - How They Did It - And What Next? Flyby? Lander?
- Why Psychology Lost Its Soul - Science Replaced It
- Chatelperronian Hominins: Disputed Neanderthal Region Confirmed In France
- No Go Area! What? What is that?
- "I don't think that much of the Kardashev scale. Especially L2,3 star vs galaxy. How would it be..."
- "When Descartes claimed ... the soul ... is eternal and indivisible... it's obvious he starts with..."
- "Oh, sorry to hear that, I hear this so often. Basically it's like propoganda I think. Propoganda..."
- "Hi mr walker... lately i havent been able to eat or drink.. and if i do sleep its during the whole..."
- "Right, California did, but prior to that there were schools in Marin with only 25% vaccination..."
- Is Parenting Kids of Human and Canine Persuasion the Same? Yes!
- Diabetes: MiniMed 670G Hybrid Closed-Loop Insulin System Is A Waypoint To An Artificial Pancreas
- Celebrate Oktoberfest with Beer Chemistry
- Littlest Consumers Doing Well, Nutrition-wise
- Herpes Vaccine Update: Exciting News, But Don't Throw Away Condoms Just Yet
- Ben & Jerry’s Asks Us to Take Big Lick of Fear & Hype
- Antipsychotic medications linked to increased risk of pneumonia in persons with Alzheimer's disease
- Multiple sclerosis misdiagnosis shows need for improved education of clinicians
- Brown adipose tissue can secrete factors that activate fat and carbohydrate metabolism
- Therapeutic Gene Delivery for Inherited Retinal Degeneration in Children
- Molecular atlas of the pancreas