Reviews & Analysis

Growth factors regulate cell behaviour, and are kept in check by inhibitors. The structure of a complex of two such proteins shows that they form back-to-back butterflies, with the inhibitor's wings stretching to embrace its partner.

Triple points describe states of matter in which three phases exist at the same time — such as solid, liquid and gas. The same phenomenon has now been found to occur between three different shapes of atomic nuclei.

Our understanding of insect flight is hampered by the difficulty of obtaining data when the insects are flying freely. But such experiments can be carried out and show butterflies to be masters of flight control.

A small fraction of Kuiper-belt objects are known to be accompanied by large moons. These double worlds may have formed in the earliest days of the Solar System through comparatively gentle gravitational encounters.

Huge amounts of methane are locked up in deposits that lie deep beneath the sea floor. New seismic images reveal that these deposits possess unexpected features that might affect their stability.

The fat-derived hormone leptin is best known for its effects on weight. But it also influences bone density, and new work reveals a role for the sympathetic nervous system in mediating this effect.

The house mouse, Mus musculus, has been inextricably linked with humans since the beginning of civilization — wherever farmed food was stored, mice would be found. Many of the advances in twentieth-century biology owe a huge debt to the mouse, which has become the favoured model animal in most spheres of research. With the completion of the draft sequence of its genome published in this issue, the mouse promises to continue to provide us with an essential resource for all aspects of biology. In this timeline, we chart the key events in the history of the mouse that led to this landmark achievement.

The aim of aerodynamic design is to reduce the drag experienced by a body, such as a car, in a flowing medium, such as air. But what happens if the body is flexible and bends in response to the flow?

The laboratory mouse has become an indispensable tool for investigators in many areas of biomedical research. The availability of the full mouse genome sequence will immeasurably advance both the character and the pace of discovery.

Many traits, including susceptibilities to some diseases, are under complex genetic control. A new way of analysing the mouse genome will be a great help in understanding the interactions involved.

One benefit of studying mice is that most of their genes have counterparts in humans. Two groups have used this similarity to study when and where the genes found on human chromosome 21 are switched on.

The free-electron laser will be a source of intense, short-wavelength radiation for a range of applications, including biological imaging. The first results from a prototype have already thrown up a surprise.

Immune cells must be taught to distinguish between invading microbes and the body's own proteins. A new study re-emphasizes the importance of a thorough education in the thymus, and identifies an essential instructor.

Genetic analysis has revealed how a small and isolated population of grey wolves found salvation in the form of the genetic variation offered by a single, immigrant male.

Ultrashort laser pulses are a valuable tool, but at these timescales a factor called the 'carrier–envelope phase' becomes important. A new technique to measure the evolution of this phase could advance laser spectroscopy.

Certain retinal neurons fire specifically in response to stimuli moving in one direction. This apparently occurs when branches of an upstream nerve cell respond asymmetrically, and link asymmetrically to the firing retinal neuron.

Old fathers are the source of more genetic mutations in their offspring than either young fathers or mothers of any age. But the apparently most plausible explanation for this effect might not hold.