Session B1
6163
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APPLICATION OF CRISPR–ENABLED GENE DRIVE APPROACH TO
ERADICATING MALARIA
Fathima Shabnam, fas32@pitt.edu, Mahboobin 16:00, Zhewen Fu, zhf14@pitt.edu, Sanchez, 10:00
Since the unveiling of the DNA structure, scientists have
endeavored to manipulate genes for the well being of
mankind. With rapid developments in genetic engineering,
researchers have turned their attention to malaria, a disease
that caused around 438,000 deaths worldwide in 2015,
demanding immediate attention from the scientific
community [1].
A popular technique, introduced by Dr. Austin Burt at
the Imperial College London in 2003, is the application of
gene drives, an approach to altering the genetic structure of a
population by spreading desired genetic traits through
certain individuals. Two proposals of gene drive application
to eradicate malaria include sterilizing female vector
mosquitoes and modifying the DNA of individual malaria
vector mosquitoes in the population. The primary advantage
of the second approach is that it raises the odds of
inheritance to almost 99 percent [2].
The gene drive system has become possible due to the
CRISPR/Cas9 technology, introduced by Dr. Jennifer
Doudna at the University of California, Berkeley. In 2012,
while studying the acquired immune system of bacteria,
Doudna’s team discovered clusters of regularly interspaced
short palindromic repeats (CRISPR) in bacterial DNA.
During incursion of viral DNA, the guide RNA (a sequence
of bacterial RNA that matches a specific region of the viral
DNA) attaches to the nuclease Cas9 (a CRISPR–associated
enzyme), which disables the function of the virus by
cleaving onto the viral DNA. Inspired by this mechanism,
Doudna’s team developed the CRISPR method to edit the
DNA of organisms, by injecting the guide RNA, Cas9 and
an additional desired DNA sequence into the cell. The
desired DNA replaces the target DNA sequence, resulting in
the possible change in any part of genomic data of an
organism [3]. Compared to former genome editing
techniques such as zinc finger nuclease (ZFN) and
transcription activator-like effector nuclease (TALEN), the
CRISPR/Cas9 technology is much more efficient in terms of
time, cost and flexibility [4].
While this raises the standard for genome editing, ethical
issues demand the attention of researchers. Some scientists
have over-stepped ethical boundaries to engineer human
embryos [5]. Further ethical dilemmas emerge when this
University of Pittsburgh Swanson School of Engineering
2016/01/29
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knowledge is applied to gene drives as the risk of ecosystem
disruption and off-target alterations increases [6].
This paper focuses on the application of CRISPR–
enabled gene drives in eradicating malaria through
genetically engineering mosquitos and will follow the
chronology of this proposal, beginning with the history, and
transitioning into the technology of gene drives, CRISPR
and the ethical implications of both techniques combined.
Since research is limited on this relatively new application of
CRISPR, we cannot further narrow our topic sentence.
Research for this paper will be conducted through reading
journals (Nature, Science), published papers, watching
Doudna’s explanatory videos, and interviewing Professor
Deiter who is doing research on CRISPR.
REFERENCES
[1] “10 facts on malaria,” World Health Organization.
(2015). (Online report).
http://www.who.int/features/factfiles/malaria/en/
[2] “Gene drive overdrive,” Nature Biotechnology. (2015).
(Online journal). pp. 1019–1021.
[3] “Jennifer Doudna (UC Berkeley / HHMI): Genome
Engineering with CRISPR-Cas9.” iBioMagazine. (2015).
(Video).
https://www.youtube.com/watch?v=SuAxDVBt7kQ
[4] T. Gaj, C. A. Gersbach, C. F. Barbas. (2013). “ZFN,
TALEN, and CRISPR/Cas-based methods for genome
engineering,” Trends in Biotechnology. (Online paper) pp.
397–405.
[5] “CRISPR crisis: Is UK researcher's human embryo gene
editing research cause for worry? | Genetic Literacy
Project,” Genetic Literacy Project, 2015. (Online article).
https://www.geneticliteracyproject.org/2015/10/26/crisprcrisis-is-uk-researchers-human-embryo-gene-editingresearch-cause-for-worry/
[6] “Should you be concerned about gene drives?,” Risk
Bites.
2015.
(Video).
http://www.youtube.com/watch?v=kgvhupiddq8
SOURCES CONSULTED
Fathima Shabnam
Zhewen Fu
A. Hammond, R. Galizi, K. Kyrou, et al. (2015). “A
CRISPR-Cas9 gene drive system targeting female
reproduction in the malaria mosquito vector Anopheles
gambiae,” Nature Biotechnology. (Online paper) pp. 78–83.
“CRISPR gene-drive mosquitoes could eradicate malaria |
Front Line Genomics,”
Front Line Genomics.
http://www.frontlinegenomics.com/2836/crispr-gene-drivemosquitoes-could-eradicate-malaria/
“Video for instructions on use of Library”. Swanson School
of Engineering. (Video).
http://www.library.pitt.edu/other/files/il/fresheng/index.html
“Jennifer Doudna (UC Berkeley / HHMI): Genome
Engineering with CRISPR-Cas9.” (2015). iBioMagazine.
(video).
https://www.youtube.com/watch?v=SuAxDVBt7kQ
This is an explanatory video on YouTube posted by
iBioMagazine in which Dr. Jennifer Doudna, the researcher
who came up with the idea of the CRISPR/Cas9 system,
explains the technology in detail. The information from this
will aid us to give a detailed explanation of the
CRISPR/Cas9 technology and inform the readers about the
importance of it.
ANNOTATED BIBLIOGRAPHY
K. M. Esvelt, A. L. Smidler, F. Catteruccia, and G. M.
Church. (2014). “Concerning RNA-guided gene drives for
the alteration of wild populations.” eLife. DOI:
10.1101/007203 vol. 3
This peer-reviewed article in eLife, an online scientific
journal, engages in a comprehensive introduction of the
application of CRISPR-Cas9 in promoting genetic
modifications among wild populations. In a systematic
approach, the article also serves to generate discussions
around the implications of CRISPR-enabled gene drives,
while offering potential failsafe solutions to the
consequences. This information serves as a foundation to the
ethics section of our paper as we will discuss the drawbacks
of this technology.
A. Hammond, R. Galizi, K. Kyrou, et al. (2015). “A
CRISPR-Cas9 gene drive system targeting female
reproduction in the malaria mosquito vector Anopheles
gambiae.” Nature Biotechnology. (online article). DOI:
10.1038/nbt.3439 Vol. 34, no. 1, pp. 78–83.
This research paper, published in Nature Biotechnology,
introduces the gene drive approach to eradicate malaria,
using CRISPR-Cas9 by targeting reproduction of female
vector mosquitos. Of the two techniques of gene drives, this
idea of sterilizing female mosquitoes to reduce the spread of
disease raises a plethora of ethical discussions. Since our
paper discusses the gene drive approach to eradicate malaria,
this research article serves as a crucial tool for understanding
this application of CRISPR.
T. Gaj, C. A. Gersbach and C. F. Barbas. (2013). “ZFN,
TALEN, and CRISPR/Cas-based methods for genome
engineering,” Trends in Biotechnology. (online article). DOI:
10.1016/j.tibtech.2013.04.004 Pp. 397–405.
This peer-reviewed paper published in Trends in
Biotechnology, provides information and limitations of preexisting genome editing tools such as ZFN and TALEN and
highlights crucial differences between them and the CRISPR
tool. This is useful, as we will discuss the purpose,
significance, and the reason why CRISPR has revolutionized
genome editing along with what improvements have to be
made with the CRISPR technology.
E. Pennisi. (2015). “Gene drive workshop shows
technology’s promise, or peril, remains far off.” Science.
(online article)
http://www.sciencemag.org/news/2015/10/gene-driveworkshop-shows-technology-s-promise-or-peril-remains-far
This news article published in the journal Science
focuses on the drawbacks of using a gene drive to eradicate
malaria. The points discussed in the article are from National
Academies of Sciences, Engineering, and Medicine (NAS)
workshop in Washington. This information will be used to
outline the primary prospective of CRISPR technology,
including its advantages and its disastrous consequences.
V. M. Gantz, N. Jasinskiene, O. Tatarenkova, et al. (2015).
“Highly efficient Cas9-mediated gene drive for population
modification of the malaria vector mosquito Anopheles
stephensi.” Proceedings of the National Academy of
Sciences of the United States of America. (online article).
DOI: 10.1073/pnas.1521077112 Vol. 112, no. 49.
This is a peer-reviewed article in the scientific journal,
PNAS. This article focuses on the more advisable approach
to using CRISPR-Cas9 gene drives to extinguish
mosquitoes’ abilities to carry plasmodium falcipurum, which
is the most common malaria parasite rather than annihilating
the entire malaria vector species. Since this is the second
techniques of gene drives, it serves as an important tool for
understanding the application and implications of this
approach.
H. Ledford . (2014). “CRISPR, the disruptor.” Nature.
(online article)
http://www.nature.com/news/crispr-the-disruptor-1.17673
This news-featured article, published in Nature,
emphasizes on the concerning ethical issues. With its ability
to engineer entire ecosystems, CRISPR-enabled gene drive
arouses consternation among researchers as to whether it is
an indispensable tool to improve life or whether it is an
unethical disruption to nature. This is going to be used for a
general overview of the technology and also for the
possibilities it holds.
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Fathima Shabnam
Zhewen Fu
Y. Fu, J. A. Foden, C. Khayter, et al. (2013). “Highfrequency off-target mutagenesis induced by CRISPR-Cas
nucleases in human cells.” Nature Biotechnology. (online
article). DOI: 10.1038/nbt.2623 Vol. 31, no. 9, pp. 822–826.
This peer-reviewed paper, published in Nature, discusses
the chances of off-target mutations from the CRISPR-Cas9
system. It was found that CRISPR RNA-guided
endonucleases are active even with imperfectly matched
RNA-DNA interfaces in human cells, producing unreliable
data in research and therapeutic applications. This
information will be used in this paper to discuss the
reliability of the CRISPR technology.
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