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Contributed by: Emily Walsh, 5/97
Target Group: Middle School

Name of Activity:  Fish and Genes

Objectives:  Discovery-based activity focused on watching fish embryos develop... Also, learn the concept of genes by looking at fish which are mutant in one gene (suggest no tail mutants).

Materials required:

• Fish embryos at various stages of development, both mutant and wild type.
• Egg water for embryos
• 10 Petri dishes--preferably deep dishes.
• Microscopes--with at least 60x magnification and light sources

Amount per student:  If petri dishes are donated and microscopes are available then the activity is free.

Possible Hazards:  

• Only to the microscopes themselves...
• Egg water could make a wet mess....

Student Organization:

• 8 Groups of 3 to a microscope/embryo set-up would be best.
• One each - materials, timekeeper, reporter

Adult Roles:

• Lead an introduction
• Each person works with 2 or 3 groups during activity
• Lead discussion of what was seen...Lead intro for activity sheet on genes

Organization of time/activity:

• 3 Minute intro--discuss need to be careful with microscopes, talk about what materials need to be picked up
• 5 Minutes to get materials
• Petri dishes per group:

1.  10 hours of development - wild type

2.  24 hours of development - wild type

3.  34 hours of development - wild type

4.  34 hours of development - mutants

Activity sheets:  Use one with places to draw what you see in each dish

• 35 Minutes to look at fish and draw what you see on activity sheet #1.
• 12 Minutes for a quick discussion of what was seen. Ask students for observations about the differences between the dishes of embryos. (I'm not sure if you want to tell them what they are looking at [i.e. what's young/old, wild type/mutant] or let them try to stage the 4 different dishes at this point. (Hand out a gene info sheet here...)
• 5 Minutes to go over the gene info sheet. Tell them the mutant has only one gene messed up - ask them what they think that gene might normally do in an embryo. Talk about the fact that there are master genes which turn legs into legs and eyes into eyes...

All about genes.....

• Every CELL in your body has a NUCLEUS.
• Every NUCLEUS contains DNA.
• DNA is a molecule made up of GENES.
• GENES are bits of DNA which if decoded make PROTEINS.
• PROTEINS are machines which do work for the CELL.
• The no tail mutant we looked at is MUTANT, or messed up, in only one of the many GENES in its DNA.
• That GENE is required for a fish to grow a TAIL
• Other GENES are required to make eyes and legs and arms and brains and hearts.

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