Danio rerio in K-12 classrooms: sparking interest in the new generation of scientists

Abstract

Zebrafish are ideal for experimental studies in the classroom because, in contrast to chicks or mammals, fish embryos are relatively easy and inexpensive to maintain, and embryonic development can be observed with common classroom equipment. The eight student-developed laboratory exercises described here have been used by students in Neuroscience Research at Sidwell Friends School. This course uses zebrafish as a vertebrate model to study genetics, development, behavior, neurobiology, regeneration, learning, and memory. The students develop protocols through collaboration with the teacher and scientists in specific fields. Through individual research, students develop and perform their own experiments, formulate and test hypotheses, learn basic laboratory and microscopy techniques, collect and analyze data, read original scientific literature, and collaborate with prominent zebrafish researchers.

FIG. 1.

This is an embryo at about 24 hours postfertilization still in its chorion. The anterior of the embryo is to the right, and the dorsal is to the bottom.

FIG. 2.

This is a breeding tank with an insert with a slit bottom that allows eggs to fall to the bottom. This prevents the adults from eating the newly fertilized eggs.

FIG. 3.

The plunger is a pipetter attached to tubing with a glass capillary inserted into the tubing. The glass capillary is inserted into the male fish to collect the sperm.

FIG. 4.

This figure shows photos of embryos developing at different rates because of their differing incubation temperatures. (A) An embryo on day 2 of development at 22°C. The anterior of the embryo is to the right, and dorsal is to the bottom. (B) An embryo after 3 days of development at 22°C, lagging behind development, still in the chorion. Anterior of the embryo is oriented upward, while the dorsal is to the left. (C) Embryo developing at 28°C after 2 days. Anterior of the embryo is to the right, and dorsal is to the bottom. (D) Embryo developing at 28°C, out of the chorion after 3 days. Anterior of the embryo is to the right, and dorsal is to the bottom. (E) Embryo developing at 33°C, out of the chorion on day 2. Anterior of the embryo is to the left, and dorsal is to the top. (F) Embryo after 3 days if development at 33°C, very far developed. Anterior of the embryo is to the left, and dorsal is to the top.

FIG. 5.

This figure documents the progression of the students' results. The columns represent melanophores of the fish in the control tank, black experimental tank, and white experimental tank, respectively. The rows represent the different days: days 3, 5, and 7, respectively. Notice how dark the fish in (B) is compared to that in (A), and how light the fish in (C) are to that in (A) only after 7 days.

FIG. 6.

This figure depicts the formation of the regenerating appendages. (A) and (B) show the blastema, or group of undifferentiated cells, forming during day 4, while (C), at a higher magnification, shows the blood vessels and melanocytes, or pigment cells within the blastema. (D), taken during day 7, shows the further growth of the fin along with the organization of the new blood vessels and appearance of pigment in this regenerated area. The fish is oriented posterior to anterior.