Development

Human stem cells are specialized cells that can be harvested from the body and engineered to turn into various tissues and organs. Perhaps the greatest potential use of stem cells is the generation of new tissues for organ transplants. Unfortunately,…

In a clutch of eggs, some zebrafish are the runts of the litter and may appear younger because of their diminutive size. This is the case for the two zebrafish above. The two are in fact 5-day old siblings. At this stage of development, the zebrafish…

If you look closely at this zebrafish embryo, you will notice bright spots that look like stars covering the entire body. The nuclei of each cell in this embryo has been labeled with a fluorescent protein so when you look at the nuclei under a…

There are a multitude of signals that elegantly orchestrate the proper development of the heart. In this image of a 3-day-old zebrafish heart, the signal that is localized to the developing atrio-ventricular valve and smooth muscle is labeled in green…

Here is the developing zebrafish heart at 3 days post-fertilization. Unlike mammals, which have four chambers, the zebrafish heart consists of only two: a single ventricle (left) and a single atrium (right). Despite the difference in the number of…

The image above shows a developing zebrafish eye 3 days after fertilization. From this perspective, we are staring directly into the eye of the zebrafish and can appreciate both its beauty and its complexity. At this stage, the cells that comprise and…

The image above shows a developing zebrafish eye 3 days after fertilization. From this perspective, we are staring directly into the eye of the zebrafish and can appreciate both its beauty and its complexity. At this stage, the cells that comprise and…

These images show cross sections of the different compartments of the developing gut in a chick embryo: esophagus (top), small intestine (middle), and large intestine (bottom), at days 6, 8, 10, and 14 (left to right). As the chick develops, the shape of…

Ant feeding on honey [Image: Fir0002/Flagstaffotos under CC-BY license] Traits that exist along a continuum, such as height, size, and behavior, vary significantly from person to person. The genetic and environmental interactions that cause these…

The natural world displays an incredible amount of innate beauty, from snow-covered mountain peaks to exotic tropical reefs. For scientists and non-scientists alike, one of its most mesmerizing features is the pigmentation and coloration of living…