Image of the Week: Zebrafish

We continue to take a closer look at some of the model organisms that have contributed to our knowledge of genetics and drug discovery. This week, the super symmetrical retina of a zebrafish.

This image, titled ‘Sunrise in the eye’, was taken using a microscope. Different cells are stained with different colours to show how the eye is developing in a three-day-old zebrafish (Dario rerio). The retina grows outward from the centre, creating a symmetrical kaleidoscope effect. The gold bullseye at the centre of the image is the lens, the red band is made of retinal stem cells that will eventually become nerve cells, and the purple band is cells that have already begun that process to connect the eye to the brain.

The zebrafish is a small, stripy freshwater fish native to northern India. As well as being common in home aquariums around the world, it is extremely popular in medical research. Being a vertebrate, it has many genes that are very similar to human genes. Plus, its eggs are transparent and grow outside the mother, which makes it relatively easy to see what is going on as the embryo develops.

Zebrafish have even been into space: Salyut 5, a Russian space station in orbit in the mid-70s, had a fishtank on board to see whether their biology changed in low gravity. Back on Earth, zebrafish are used to understand human genetics, development and disease, but they have tricks of their own that we would like to try and mimic – for example, while our bones can mend themselves, our hearts don’t, but zebrafish can regenerate their heart muscle. If we could learn how they do that, it might lead to new treatments for people after heart attacks.

You can read more about how this image was made on the Wellcome Image Awards website – it was a winner in 2011.

Image credit: Dr Kara Cerveny & Dr Steve Wilson, Wellcome Images

Wellcome Images is one of the world’s richest and most unusual collections, with themes ranging from medical and social history to contemporary healthcare and biomedical science. Over 100,000 high resolution images from our historical collections are now free to use under the Creative Commons-Attribution only (CC-BY) licence.