What Happened to the Fish?
Dr. Tanguay makes observations of the fish experiment. After about
five days, he notices that the zebrafish embryos in the experimental
treatment are deformed. The experimental treatment adult zebrafish
are unaffected as are fish and embryos in the two control tanks.
The deformed embryos do not survive to become adults. When too
many embryos are deformed and die, the fish population decreases.
Luckily, Dr. Tanguay and his research team specialize in the field
of developmental toxicology.
What is Developmental Toxicology?
Toxicology is the study of harmful substances. Developmental
toxicology is the study of how those substances affect
organisms during early stages of growth.
In all animals, the development stage begins when an egg is fertilized
and lasts until the egg hatches (in the case of zebrafish) or until
birth (in the case of mammals like humans and mice.)
If an embryo is exposed to a developmental toxin —a
chemical that harms a developing organism—it can suffer physical
changes (also called morphological changes; “morph“-means
shape or form) and become deformed. These developmental toxins
change the body’s normal gene expression,
or the way the body reads its instructions from genes in
DNA.
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