A Lesson From Some Mutant Worms

by Gabrielle DeMarco on April 30, 2009

Take a look at some beautiful images of some mutant worms. These are Caenorhabditis elegans to be exact from the laboratory of assistant professor of biology Fern Finger. Finger is studying the function of two very similar genes, asfl-1 and unc-85. These genes are both present in C. elegans, but they are also present in all animals, including humans. With a better understand of the role of each of these genes, Finger could provide important information on the role these genes play in our development.  The image also provides a nice opportunity for a very basic crash course in an often-used microscopy technique for any amateur scientists among you.

This image is from her most recent paper published in the journal Developmental Biology and shows where cell replication occurs in the sex organs of worms with varying gene mutations. The first photo is a normal worm ovary with no genetic mutations, called wild-type in the lab. Throw that term around the classroom or office and you are sure to sound like a professional. The second is missing asfl-1. The third is missing unc-85. The fourth is missing both asfl-1 and unc-85. This has obvious implications for Finger’s findings, but it also creates a very beautiful and classic biological image using a standard microscopy technique called florescent tagging.

To create the red and blue image, Finger injected a florescent nucleotide into the worms’ ovaries. Nucleotides are the building blocks of DNA. Where the fluorescent nucleotides are present, DNA is being created. Under the ultraviolet light of a fluorescent microscope the tag glows red, indicating where exactly DNA is being produced, if at all, in the each of the animals.

These glowing fluorescent tags are just like the fluorescent markings that students make in their textbooks – they point in the most important aspects of what you are studying. Without them, the image would just be a dark, jumbled blob. Other types of stains are drawn to different types of molecules and chosen by the scientist depending on what exactly they hope so see on the other end of the microscope. Depending on the stain used or the software to process the image, the stain could glow a variety of colors. There is many a biology student who spends hours playing with the colors of their molecules.

In this case, you will notice that one of these images in not like the others. Can you guess which one? The final image of a worm that is missing both the asfl-1 and unc-85 genes is surprisingly devoid of red. The lack of a rosy glow indicates that no DNA is being replicated in the sex organs of this animal. This is obviously a problem for this animal’s future shots at producing baby worms and proves that both of the genes play an important role in the normal reproductive health of an animal. Both genes obviously work together in some way during the course of normal development. It is an important finding for Finger and colleagues.

It is a cool image that provides even cooler insight into basic gene function.