Literature Review

1. M A R K E R : P L E A S E M A R K T H I S W O R K F O R C O N T E N T A N D I D E A S A N D N O T
F O R A C C U R A T E S P E L L I N G A N D P U N C T U A T I O N U N L E S S T H I S I S A
R E Q U I R E M E N T O F A S S E S S M E N T .
Bioscience & Chemistry Programme
Professional & Scientific Practice 3
From Dolly to Today: A Review of Cloning in Conservation
Strategies for Endangered Species and Genetic Diversity
Preservation
By Madihah Ismail
Submitted Date: 27/02/2024

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Table of Contents
Abstract................................................................................................................................. 3
1.0 Introduction................................................................................................................. 3
2.0 Cloning in Conservation Strategies for Endangered Species ...................................... 4
2.1 Historical Evolution of Cloning: Dolly the Sheep...................................................... 4
2.2 Cloning Technologies.............................................................................................. 5
2.3 Applications in Endangered Species Conservation ................................................. 6
2.4 Challenges and Ethical Considerations ................................................................... 8
3.0 Conclusion.................................................................................................................. 9
4.0 References ................................................................................................................11

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Abstract
This literature review, titled "From Dolly to Today: A Review of Cloning in Conservation
Strategies for Endangered Species and Genetic Diversity Preservation," offers a
comprehensive exploration of the evolution of cloning from livestock enhancement to its
potential in biodiversity conservation. It outlines the historical significance of animal cloning
and the subsequent ethical debates spurred by milestone achievements. This literature review
delves into genome editing's transformative impact on animal breeding, with a focus on bovine
embryos and a proposed innovative breeding scheme. The review extends to discuss the
application of cloning in endangered species conservation, presenting case studies and
evaluating its potential to revive extinct species. Ethical considerations are emphasized,
exemplified by a case study on the black-footed ferret. Furthermore, it underscores the
importance of responsible cloning applications and the need for further research. The literature
review successfully synthesizes historical context, scientific advancements, and ethical
considerations, contributing to a comprehensive understanding of cloning in conservation and
genetic diversity preservation.
1.0 Introduction
Animal cloning, particularly in domesticated animals, has significantly
contributed to targeted and accelerated livestock improvement. The primary objective
of animal breeding, aiming to select beneficial DNA variants, encounters inefficiencies
due to the limited genetic variation within individual animals. The emergence of genome
editing technology has provided a solution by allowing the direct introduction of
desirable DNA variants, overcoming the challenges of traditional breeding methods and
accelerating genetic progress. The historic milestone of Dolly the sheep's cloning in
1996 marked the initiation of widespread interest in animal cloning. This breakthrough
sparked global ethical debates regarding the implications of cloning technology.
Subsequent achievements, including Cumulina the Mouse (Yanagimachi et al., 1998),

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Noah the Gaur (Bird, 2001), Snuppy the Dog (Lee et al., 2005), and Macaque monkeys
(Cyranoski, 2018), have paved the way for exploring cloning in conservation efforts to
safeguard endangered species and maintain genetic diversity.
In the background, the term 'cloning' has undergone a historical evolution,
encompassing various meanings from natural reproduction in bacteria to modern
molecular technologies in vertebrates. This literature review from Swegen, Appeltant,
and Williams, 2023, critically evaluates cloning technologies beyond humans and
rodents, examining their readiness and applicability for conservation efforts in
endangered animal species (Swegen, Appeltant, and Williams, 2023).
2.0 Cloning in Conservation Strategies for Endangered Species
2.1 Historical Evolution of Cloning: Dolly the Sheep
Dolly the sheep was the first-ever cloned mammal, and scientists made her
using adult mammary gland cells in a pretty complicated way (Panno, 2014). However,
it didn't work so well at first. Out of 277 tries, they only got one successful clone. It was
like trying a lot but succeeding just a little. So, they changed their approach and started
using cells from baby animals instead of adults. This way worked better, and they could
make more baby animals that were clones. Even though cloning had some problems,
it was better than the old way of making special animals with specific genes. With
cloning, they could choose cells that had the genes they wanted, making the process
more straightforward. This was a big step forward in how scientists could change the
genes of animals, making it more efficient and precise (Pennisi, 1998). Looking at
Dolly's story in a bigger picture of animal research in Edinburgh, where she was born,
it becomes clear that she was not just a one-time thing (Wilmut, Campbell, and Tudge,
2001). Her birth was a crucial part of making animals that could help with medicine and
other important things. The way people did science and experiments also changed
during the 1970s and 1980s because of new ideas and the need to show that science

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could be useful. Dolly went from being just a tool to make animals better for farms to
becoming a symbol of a new era in cloning. This shows how science, society, and
culture all mix together and change over time (García-Sancho, 2015).
2.2 Cloning Technologies
The progress in genome editing technology has brought about a significant
transformation in animal breeding, effectively addressing the long-standing
inefficiencies associated with limited genetic variation. In the context of animal
breeding, the primary objective is to pick out beneficial DNA traits, a task made
challenging by the restricted genetic diversity found within individual animals (Stock
and Reents, 2013). This is like trying to find the best parts from a small collection.
Genome editing technology acts as a game-changer by allowing scientists to directly
add the desirable DNA traits, making the process of animal breeding more up-to-date.
The literature review from Mclean, Oback, and Laible, 2020, narrows down its focus to
genome editing in bovine embryos, offering a unique perspective. It suggests an
inventive breeding approach that aims to tackle the difficulties associated with
Homology-Directed Repair (HDR) editing efficiency. It's like finding a new and better
way to edit the genes in cows to make them healthier or more useful. This proposed
scheme holds the promise of enhancing the efficiency of genetic improvements in
livestock, representing a significant step forward in the way we make animals better for
various purposes (Mclean, Oback, and Laible, 2020).
The proposed breeding scheme intricately integrates embryo-based genomic
selection with precise multi-editing techniques. This approach seeks to address the
limitations posed by low HDR editing efficiency and the production of mosaic embryos.
By leveraging embryonic cloning with elite edited blastomeres or embryonic pluripotent
stem cells, the breeding strategy aims for accelerated genetic improvement in livestock.
This targeted and efficient approach holds the potential to revolutionize livestock

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improvement by allowing for the incorporation of beneficial variants and novel traits
from outside the breeding population within a single generation. Biodiversity
conservation is confronted with numerous challenges, including the endangerment and
extinction of many species. Somatic cell nuclear transfer (SCNT) emerges as a
promising tactic to counteract extinction threats, offering avenues for permanent gene
editing, genetic modification, and controlling invasive species. Despite its limitations,
SCNT presents opportunities for significant progress in biodiversity preservation and
species conservation through the integration of advanced genetic techniques (Iqbal et
al., 2021). In figure 1.0, the data illustrate the survivability rates of SCNT clones.
2.3 Applications in Endangered Species Conservation
The application of cloning in endangered species conservation holds significant
promise, as evidenced by various case studies and experiments showcased in this
literature. These endeavors highlight the potential of cloning technology to rescue
Figure 1.0: The survivability of SCNT clones is influence with reprogramming
efficiency. Most reconstructed embryos do not survive past the early stages, either
before implantation or just after it begins. Some clones make it to the point of birth,
while only a minute fraction progresses to adulthood (Lim, Lorthongpanich, and Solter,
2013). Retrieved from: (https://www.sciencedirect.com/topics/agricultural-and-
biological-sciences/cloning-animals)

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species on the brink of extinction. The literature from Kosch et al., 2022, extensively
reviews these cases, offering insights into the successes and challenges encountered
in the application of cloning for conservation purposes. One key area of exploration is
the feasibility of using cloning to revive extinct species. It delves into the possibilities,
discussing both successful attempts and challenges faced in this ambitious endeavor.
Genetic intervention, including artificial selection and synthetic biology, emerges as a
valuable tool in altering phenotypes for adaptation in threatened species. The
traditional approach of conservation breeding programs, while crucial, is not without
limitations. The focus shifts to Targeted Genetic Intervention (TGI), an alternative
approach drawing on proven methods from model organisms and agriculture. Synthetic
biology and artificial selection are proposed as effective means to restore species
facing intractable threats such as infectious diseases and climate change (Kosch et al.,
2022).
In the context of animal conservation, the discussion on cloning is centred on
producing genetically identical individuals to rescue endangered or extinct species.
Recent advancements, including induced pluripotent stem cells and embryo splitting,
expand the scope beyond traditional somatic cell nuclear transfer associated with
cloning. The literature emphasizes the necessity of a comprehensive evaluation, urging
scrutiny of both the biological and ethical implications of cloning in species conservation
(Cowl et al., 2024). Genetic rescue, a strategy involving the introduction of unique
genomes into a population's gene pool, may lead to scenarios where cloning, utilizing
cryopreserved materials, becomes a crucial tool. This process involves making copies
of certain genetic materials stored in a frozen state to save or enhance the genetic
diversity of a species. The literature stresses the need for a thorough ethical analysis
of cloning in conservation, particularly when applied to genetic rescue efforts. The
examination of ethical dimensions, using the black-footed ferret as a case study,

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provides a practical example guiding responsible decision-making in the broader realm
of cloning technology in biodiversity conservation (Sandler, Moses, and Wisely, 2021).
As cloning technology increasingly shapes conservation strategies for
endangered species and genetic diversity preservation, understanding and addressing
the ethical implications become imperative. These insights contribute positively to the
well-being of species and ecosystems, aligning with the broader goals of biodiversity
protection and enhancement. The literature underscores the importance of responsible
actions and ethical considerations as we explore innovative methods to safeguard and
elevate biodiversity on our planet.
2.4 Challenges and Ethical Considerations
The literature review identifies and analyzes future challenges in genetic
approaches to biodiversity conservation, shedding light on critical issues that need
consideration. Challenges include resolving taxonomy uncertainties, managing
fragmented wild populations, and implementing explicit management for captive
populations. The emergence of low-cost genome sequencing, while presenting
opportunities, introduces new challenges. The call for simple, inexpensive means to
globally monitor genetic diversity emphasizes the evolving landscape of genetic
conservation efforts (Frankham, 2010). In addition to these challenges, the ethical
considerations associated with genetic manipulation for conservation purposes. This
involves a profound analysis of the ethical implications of altering genetic material,
including potential consequences for individual health and viability, and the broader
impacts on ecosystems. Balancing scientific advancements with ethical responsibility
becomes paramount as we navigate the complexities of genetic interventions in
biodiversity conservation. Figure 2.0 shows the percentage of Americans for and
against animal cloning.

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3.0 Conclusion
In conclusion, this literature review highlights the historical evolution of cloning, from
Dolly the sheep to recent advancements in genetic editing technologies. Animal cloning,
instrumental in livestock improvement, is now being explored for its potential in biodiversity
conservation and genetic diversity preservation (Ahmad and Hamid, 2023). This review
emphasizes the challenges and opportunities in genetic approaches to biodiversity
conservation, ranging from taxonomy uncertainties to the application of genomic tools in
managing wild and captive populations. As the world faces an increasing number of
conservation-reliant species, responsible and ethical applications of cloning technology are
crucial for the preservation of endangered species and the promotion of genetic diversity
(John, 2023). Throughout the discussion, the call for further research echoes, urging scientists
to continue exploring the potential of cloning in the preservation of endangered species and in
Figure 2.0: It illustrates the percentages of Americans for and against animal cloning.
The bad things that happen to animals from cloning can be looked at in two ways.
Looking at it closely, the worst things are pain and suffering that animal go through
when they're cloned. When looking at it in a wider view, cloning can also harm other
animals or species that are in danger. (Sinha, N., Patil, S., Kesigan, U., Chaitanya, T.,
Panigrahy, S., & Tandon, G. 2019). Retrieved from: https://shorturl.at/cpDG6

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biomedical research projects for studying diseases. The evolving landscape of genetic
technologies opens new possibilities, and a responsible approach is essential to harness their
benefits for the greater good of biodiversity conservation. The literature review has
successfully synthesized historical context, scientific advancements, and ethical
considerations, providing a comprehensive understanding of cloning in the context of
conservation strategies and genetic diversity preservation.

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4.0 References
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Swegen, A., Walker, S. L., & Williams, S. A. (2024). Cloning for the Twenty-First
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Crozier, R. H. (1997). PRESERVING THE INFORMATION CONTENT OF SPECIES:Genetic
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Cyranoski, D. (2018). First monkeys cloned with technique that made Dolly the sheep. Nature
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Iqbal, A., Ping, J., Ali, S., Zhen, G., Kang, J. Z., Yi, P. Z., Huixian, L., & Zhihui, Z. (2021).
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