In situs

In situ hybridization (ISH) is a technique that allow you to visualize a gene’s location. The location is typically determined at the level of the cell or tissue region. However, chromosome painting is also a form of in situ and has a better resolution. In general, if a scientist is talking about ‘in situs’ or WISH, they are referring to the form that shows where a gene is being expressed.

In situ hybridization is like a Google search, where the probe is our search term.

At the most basic level, ISH simply attaches a labeled probe of DNA or RNA (nucleic acids) to other DNA or RNA. You can think of in situs as the Google search of biology. In Google, you can search a variety of media (websites, videos, or images) based off whatever you put in the search box. Using in situs we can search the various forms of nucleic acids based off the probe whose sequence is known.

Thus, many different techniques with a variety of goals fall under the broad category of ISH. This can lead to a lot of confusion even within the field of biology. At a conference dinner I was discussing my work on developing FISH for sticklebacks and at least one PhD at the table thought I was talking about chromosome painting for most of the conversation until what I was saying stopped making any sense. So if you find this confusing, you are in good company.

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Stickleback fish

A mostly blue fish with a bright red throat. Meet your typical stickleback dad. My research is based on understanding how genes contribute to his behavior.

You can tell this is a male ready to become a dad because of his blue color and the red-orange color under his throat. Its only during the summer breeding season that he will look like this. Not all males will color up this brightly as it depends on a number of factors including the amount of light and the surrounding environment (gravel color). This particular male has improvised a nest out of small pebbles in his tank that you can see to the right of the plant. Normally, stickleback fish use algae and sand to build nests, but he wasn’t given any.

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