When it comes to regrowing tails, neural stem cells are the key

Cut off a salamander's tail and, in a few weeks, a near-perfect replacement grows. Do the same to a lizard and a new tail will regrow, but it won't be the same as the original. By comparing tail regeneration between the two ...

A 3-D model of a human heart ventricle

Harvard University researchers have bioengineered a three-dimensional model of a human left heart ventricle that could be used to study diseases, test drugs and develop patient-specific treatments for heart conditions such ...

Why we make blood cells in our bones

In humans and other mammals, the stem cells that give rise to all blood cells are located in the bone. But in fish, blood stem cells are found in the kidney. Since the late 1970s, when biologists first realized that blood ...

A first look at the earliest decisions that shape a human embryo

The factors that shape the destiny of a cell, like that of a fully formed person, remain something of a mystery. Why, for example, does one stem cell in a human embryo become a neuron rather than a muscle cell? And why does ...

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