Genetically engineered zebrafish that glow green under fluorescence help scientists track how pollutants affect the body. When exposed to chemicals like bisphenol A, different organs of the fish like the heart and eyes glow, illuminating what tissues are impacted. This helps researchers better understand how these endocrine disrupting chemicals mimic hormones and cause issues like changing fish gender and links to cancers in people. The fluorescent technology is currently limited to fish under 6 days old, but future work aims to breed fish without skin pigment to observe reactions in adult fish as well.

1. FISH GLOW GREEN AFTER
GENETIC ENGINEERING
(An Update on Genetic Engineering)
Ronnie Z. Valenciano Jr. BSE 4B

2. What problem does it addresses?
 It’s the endocrine disruptors. These are
substances that are found in:
a. industrial products
b. female contraceptives
 The chemicals mimic the actions of sexual
hormones, resulting in various reproductive
problems in both people and animals.

3. What does it do?
 Fluorescence helps track what pollutants
do to the body.
 A genetically engineered fish that glows
green from the inside out is helping
illuminate what pollutants do inside the
body.

4. What does previous research
tells about this chemical?
 This chemicals cause:
a. Fish to change gender
b. In people, this have been associated with
lower sperm counts and breast and
testicular cancers
This is spearheaded by Charles Tyler at the
U.K.'s University of Exeter.

5. How it is done?
 Put genetic elements within the zebrafish
[embryos].
 Exposed the zebrafish to varying levels of
chemicals known to affect the hormone
estrogen.
 Then used a microscope to see which of the
small fish's organs glowed—and thus
responded—to the chemicals.

6. What are the findings?
 The heart glows particularly in response to
bisphenol A.
 The chemicals light up other parts of the
fish's anatomy, including its eyes and
skeletal muscles.
 Its often been assumed that these chemicals
impact the liver or testes or ovaries, but in
these fish they’ve identified them in many
different tissues, including parts of the brain.

7. Limitation of fluorescent technology
 The fluorescent technology is limited
to fish younger than six days old,
because their skin has yet to develop
pigmentation that would interfere
with observing the fluorescence.

8. What’s the next development?
 The next phase is breeding these fish
with a strain that lacks pigment in the
skin, which would allow the team to
observe the fluorescent reactions in
adult fish as well.

9. Zebrafish glow green under the
microscope.
Reference: http://news.nationalgeographic.com/news/2012/04/120423-
fish-glowing-pollution-bpa-environment-science/#ng_comments