Pigs to the Rescue ■ 171controlling gene expression. Some of it has architectural functions,
such as giving structure to chromosomes or positioning them at
precise locations within the nucleus. Given that these sections
of DNA are noncoding, does it matter if they contain replication
errors? Explain your reasoning.
Leveling Up
(^15) What do you think? In another line of research directed at
solving the shortage of organs available for transplantation,
scientists have been working feverishly on generating human
tissues and organs using human induced pluripotent stem cells
(iPSCs). These cells, which have the ability to transform into
many different cell types, start as a patient’s own skin cells
and are treated to attain an undifferentiated, or embryonic-like,
state. Scientists then direct them with growth factors to become
kidney cells, liver cells, or any other cell type needed. For more
information, see https://www.cirm.ca.gov/patients/creating-new-
types-stem-cells.
Read the article “Eight Tiny Organs Grown by Scientists,”
about the potential of iPSCs to fill the transplantable organ void
(http://www.insight.mrc.ac.uk/2015/07/20/eight-tiny-organs-
grown-by-scientists). Using the information in this article, make a
list of pros and cons for both pig organs and iPSC organs. Reflect
on which option you think is the better course of action.
(^16) Write Now biology: next-generation GMO Read the article
“CRISPR Brings an Early Harvest” (http://www.genengnews.com/
gen-news-highlights/crispr-brings-an-early-harvest/81253507),
which describes a new way to produce GMO tomatoes without
using standard gene transfer techniques. Write a letter to your
state or federal legislator expressing your opinion either for or
against this new technology for creating GMO foods. Cover the
following points in your letter.
a. Explain how CRISPR-Cas9 technology works, comp aring and
contrasting it to traditional GMO technology.
b. Describe how the CRISPR system was applied to the plants in
the article.
c. In your final paragraph, try to persuade your government
representative to either endorse or condemn this technology for
improving crop yield and quality, using specific examples.
For more, visit digital.wwnorton.com/bionow2 for access to:
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