Understanding embryo development moves forward thanks to biology and maths
Research aimed at understanding the mechanisms underlying embryo development has taken a step forward thanks to collaborative work between biology and mathematics. A study of wing formation in the fruit fly (Drosophila melanogaster), led by the researchers Marco Milán and Javier Buceta, both in Barcelona, has led to the discovery of a new genetic function involved in this process, and furthers
our understanding of the internal laws which regulate it.
The development of a living being is based on general laws written into the genetic code of each cell and which enable the cell to develop a specialist function, modifying the way they divide, their form and their behaviour. These changes are coordinated through a series of instructions that must be correctly interpreted within the cell, and this means that the information must pass along a
pathway of signalling molecules. These pathways have been conserved across evolution, and therefore studies using models such as the fruit fly provide information about these same processes in humans and other animals.
The Developmental Biology of Drosophila Group from the IRB Barcelona, led by Marco Milán, studies the signals that guide wing development in Drosophila. The wings are generated from a set of cells grouped into different segments or compartments that never mix with one another, and which enable the symmetrical construction of the dorsal and
ventral parts starting from a given limit or border. This process of subdivision into compartments also takes place during the formation of the vertebrate central nervous system, and the genes and signalling pathways involved are conserved in both Drosophila and vertebrate species.
Although biologists already had an intuitive idea of how the limit or border between these compartments was generated, there had been no systematic study taking into account all the relevant elements. Therefore, and with the backing of a group led by Javier Buceta, they decided to use mathematical modelling to better understand the internal mechanisms which regulated this process. In this way
they identified certain interactions in the signalling pathways that brought to light a number of contradictions and showed that a key step was missing in their model. As Milán explains: “Thanks to this computer simulation we have found a new genetic function that ensures the stability of the system and has enabled us to test its robustness. This study shows that modelling is a highly useful tool
for describing in silico new properties of a biological system and being able to corroborate them subsequently in vivo”.
In this regard, Buceta, who leads the SiMBioSys group, dedicated to modelling biological processes, explains that “the advantage of these modelling techniques is that they can simulate genetic and cell interactions as a set of mathematical equations and, therefore, to determine the feasibility of a biological mechanism”. In order to study the
stability of the system they conducted around 45,000 different in silico experiments, introducing variations in twenty parameters. The results have enabled them to identify the most important system parameters and showed that the biological mechanism maintained its functionality in 91% of the cases analyzed. According to Milán and Buceta “this study confirms the hypothesis that if this gene
network has been maintained across evolution in both vertebrates and insects, it is precisely because it is highly stable and robust”.
This week, researchers from the University of Cambridge will be arriving at the Summer Science Exhibition of the Royal Society armed not with the latest in cutting-edge lab technology, but an assortment of simple toys.
But while many of these playthings may look like Christmas stocking-fillers purchased from the gift shop at a museum, their behaviour is helping scholars to understand the evolution of weather patterns and the magnetohydrodynamics of spinning stars and planets. They include spinning eggs that rise against gravity, objects that spontaneously reverse their sense of spin and discs that roll at an
accelerating rate before coming to a standstill. In each case, their behaviour has been baffling some of the sharpest scientific minds for years.
"Understanding the behaviour of spinning toys can teach us a lot about some of the fundamental principles of dynamics," Dr Tadashi Tokieda, College lecturer at Trinity Hall, Cambridge, explained. "The toys themselves are very simple, but the way in which they behave is so strange that they have intrigued anyone who has studied mechanics at graduate level. One of the things we hope to point out
is that some of the most important experiments can take place not in the lab, but in daily life. Good scientists take toys seriously."
One example of a toy that seems to defy the laws of physics is the "rattleback" - a small, symmetrical canoe-shaped object that spins smoothly in one direction, but when spun the other way rattles and reverses its motion. Its mysterious behaviour was this year explained in a paper by Professor Keith Moffatt FRS, also at Cambridge University, and Dr
Tokieda, as being a subtle effect of what is known as chirality – the result of the object's skewed mass distribution.
The behaviour of this toy could offer insight into a bigger problem. Every million years or so, the Earth's magnetic field reverses, causing the planet's magnetic north and magnetic south to interchange. Scientists are still at a loss as to what causes this, but the rattleback toy mimics certain fluid dynamical processes in the Earth's liquid core that are responsible for the excitation of its
"In the case of each toy that will be on display, mathematics, coupled with computation and high-speed photography, and above all simple, imaginative experiments that everyone can do, is helping us to explain their surprising and behaviour," Dr Tokieda added.
The Royal Society's Summer Science Exhibition is held annually at the Royal Society, the UK's national academy of science. The event is free and open to the public. This year, 23 interactive exhibits will be on show presenting the best in UK science, engineering and technology. During the four days, more than 4,000 people are expected to explore the exhibition. The event will run from Monday 2
to Thursday 5 July. Other maths on display at the exhibition include sound waves, extreme pressure and optical illusions.
The geometry that gives rise to rainbows may help scientists to find out whether other planets contain water, which is necessary to sustain life. Rainbows are formed because light rays are bent, or refracted, and scattered as they enter droplets of liquid that hang in the atmosphere. The refraction occurs because light waves are slowed as they enter the droplet — think of a shopping trolley
slowing down as you push it onto a lawn at an angle, and changing its direction as a result. The amount by which the light rays are slowed, and hence bent, depends on the liquid's consistency and is measured by its refractive index. Thus, different liquids give rise to rainbows at different angles, a fact that enabled researchers to determine that the clouds of Venus are droplets of
concentrated sulfuric acid. Researchers now suggest that the same approach could be used to detect clouds made of liquid water in a planet's atmosphere.
Plasma astrophysicists at the University of Warwick have found that key information about the Sun's "storm season" is being broadcast across the solar system in a fractal snapshot imprinted in the solar wind. This research opens up new ways of looking at both space weather and the unstable behaviour that affects the operation of fusion powered power plants.
Solar wind consists of a stream of plasma, mainly protons and electrons, that are ejected by the Sun's corona. On its way out the wind interacts with the Sun's magnetic field, broadcasting it across the universe. The researchers, led by Sandra Chapman, measured the strength of the magnetic field in the solar wind. They found that when the Sun is at the peak of its 11-year cycle, the graph they
were plotting turned into a fractal. At this point the solar corona was at its most active, stormy and complex, due to sunspot activity, solar flares, etc. When the corona was quieter no fractal patterns were found in the solar wind.
This new information will help astrophysicists understand how the solar corona heats the solar wind and the nature of the turbulence of the solar wind with its implications for cosmic ray flux and space weather.
The techniques used to find and understand the fractal patterns in the solar wind are also being used to assist the quest for fusion power. Researchers in the University of Warwick's Centre for Fusion, Space and Astrophysics (CFSA) are collaborating with scientists from the EURATOM/UKAEA fusion research programme to measure and understand fluctuations in the world leading fusion experiment
MAST (the Mega Amp Spherical Tokamak) at Culham. Controlling plasma fluctuations in tokamaks is important for getting the best performance out of future fusion power plants.
Live maths - tangled DNA, the Big Bang and musical superstrings
Twisting, Coiling, Knotting: Maths and DNA Replication
The proportions of a DNA molecule in a human cell are equivalent to a 2000-mile-long rope packed inside the Millennium Dome. When DNA replicates, it spins at an astonishing 10 turns per second. Therefore, it is hardly surprising that DNA can become highly twisted, super-coiled and even knotted! To understand this phenomenon, the molecular biologist must grapple with the mathematical concepts
of twisting, writhing and knotting. In this highly-illustrated talk Professor Michael Thompson FRS will experiment with strings and rubber bands (bring your own!) to explore the geometrical rules which underlie the transmission our genetic code.
In honour of the Large Hadron Collider, the Dana Centre is holding an evening dinner and discussion attended by the expert James Gillies from CERN. There'll be slide shows and photographs and a two-course meal inspired by particle physics.
When: 15th of May 2007, 6.30pm - 8.30pm
Where: Dana Centre, 165 Queen's Gate, London SW7 5HE
Tickets: £15 per person, including a two-course meal and a drink. Tickets have to be booked by calling 0207942 4040 or e-mailing firstname.lastname@example.org.
Age range: this event is open only to those over 18 years of age.
More information: Visit the Dana Centre site.
Also the Science Museum in London has put on an exhibition in honour of the Large Hadron Collider. The exhibition is free and will run until the 7th of October 2007.
Superstrings - a Musical Journey through Time and Space
You probably knew that Einstein was a great scientist, but did you also know that he played the violin? In this unique double act a virtuoso violinist and the head of the department of particle physics at Oxford University combine the electricity of a live musical performance with an insight into the deepest corners of the Universe. The lecture explores Einstein's life, both in science and in
music, from his theories that shaped space and time, to modern ideas in particle physics.
When: 18th of May 2007 5pm-7pm
Where: Science Oxford, 1-5 London Place, Oxford, OX4 1BD
Tickets: £6.50, £4.50 concession, available from The Oxford Playhouse on 01865 305305.
More information: The Oxford Trust
Scientists are currently building the largest machine in the world in order to understand the smallest fragments of our universe. Their insights will throw light on some of the biggest questions there are - how did the universe start, what is it made of, and how will it end? The machine is the Large Hadron Collider (LHC) and it is buried up to 175m below ground in a huge circular tunnel close
to Geneva. To prepare for its inauguration at the end of this year, the Science Museum has put on a special exhibition entitled "Big Bang". The accompanying website tells you all you need to know about the collider and the science behind it. It's accessible for everyone from school age onwards, no previous knowledge required.