Gene Editing and Ethics Quiz

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Questions and Answers

What is the primary outcome of germinal genetic modification?

Temporary changes in somatic cells

No changes to the genome

Permanent changes in reproductive cells (correct)

Reversible modifications that can be cured

What major ethical concern was raised in the Jiankui case regarding the gene editing of embryos?

The research was conducted with full parental consent

It involved enhancing a genetic trait rather than treating a disease (correct)

The process was thoroughly peer-reviewed

The experiment had a clear therapeutic benefit

Which DNA repair mechanism is associated with random insertions or deletions that can lead to mutations?

Nonhomologous end-joining (correct)

Nucleotide excision repair

Homology-directed repair

Base excision repair

What was the significance of the 2018 event involving the twins Lulu and Nana?

They were the first humans born after germline modification Signup and view all the answers

What main risk is associated with gene editing that results in mosaicism?

Presence of varied alleles within the edited embryos Signup and view all the answers

Which gene was targeted in the Jiankui case for modification related to HIV protection?

CCR5 gene Signup and view all the answers

What is the main criticism regarding the benefit-risk balance of Jiankui's experiment?

The risks outweighed the potential benefits Signup and view all the answers

Which of the following statements about homology-directed repair (HDR) is accurate?

It is more efficient than nonhomologous end-joining Signup and view all the answers

What type of enzyme is an endonuclease?

An enzyme that cuts DNA Signup and view all the answers

What does CRISPR stand for?

Clustered Regularly Interspersed Short Palindromic Repeats Signup and view all the answers

Which gene editing tool is characterized as being more difficult and expensive than CRISPR?

TALENs Signup and view all the answers

Who were the key figures in elucidating the mechanism of CRISPR/Cas9 in 2012?

Jennifer Doudna and Emmanuelle Charpentier Signup and view all the answers

What are the three phases of the natural CRISPR system?

Acquisition, expression, and interference Signup and view all the answers

What is the purpose of the trial evaluating EDIT-101?

To assess safety, tolerability, and efficacy for an inherited form of blindness. Signup and view all the answers

What gene is associated with Leber congenital amaurosis 10 (LCA10)?

CEP290 Signup and view all the answers

Which experimental treatment showed promise for an inherited form of deafness?

Gene therapy related to otoferlin. Signup and view all the answers

What is the significance of the case of Aissam Dam?

He exemplifies successful gene therapy for hearing loss. Signup and view all the answers

What biotechnological concern was raised regarding CRISPR technology?

Its potential impact will begin with agricultural applications rather than medical ones. Signup and view all the answers

What was the outcome of the PRRS virus inoculation in genetically modified piglets?

Modified piglets remained healthy while regular pigs fell ill. Signup and view all the answers

What was the primary goal of the clinical trials mentioned in the context of gene therapy for deafness?

To evaluate efficiency in restoring hearing. Signup and view all the answers

Which statement about the first experimental programs in gene therapies is true?

The United States, Europe, and China are all involved. Signup and view all the answers

Which crop is made resistant to powdery mildew disease through gene editing?

Triticum aestivum Signup and view all the answers

Which gene is targeted to confer resistance to bacterial blight in rice?

OsSWEET11 and OsSWEET14 Signup and view all the answers

What type of changes does gene editing primarily introduce into crops?

Small alterations in existing genes Signup and view all the answers

In the context of regulations, gene-edited crops in the European Union are treated the same as which of the following?

Conventional genetically modified organisms Signup and view all the answers

Which disease is eliminated in Cucumis sativus L through targeted gene editing?

Ring spot and vein yellowing Signup and view all the answers

What distinguishes gene editing from traditional GMOs?

Gene editing enhances protein levels already present in organisms. Signup and view all the answers

Which disease is associated with Arabidopsis thaliana?

Turnip mosaic virus Signup and view all the answers

Which of the following crops is treated to develop resistance against the leaf thickening disease?

Nicotiana benthamiana Signup and view all the answers

What will occur if one parent carries two disease-causing alleles?

All children will inherit the disease-causing genotype. Signup and view all the answers

What is true about expectant mothers who carry two disease-causing alleles?

All offspring would inherit the disease-causing genotype. Signup and view all the answers

What is a characteristic of X-linked recessive diseases?

All male offspring will inherit the disease despite their mother's genotype. Signup and view all the answers

Which statement reflects the ethical concerns of somatic gene editing (GE)?

Somatic GE involves contentious ethical issues. Signup and view all the answers

What is a possible outcome if both parents carry two disease-causing alleles?

At least some children will inherit the disease. Signup and view all the answers

Why might research efforts be directed away from certain genetic disease studies?

Due to potential for controversial ethical implications. Signup and view all the answers

What determines whether male offspring are affected by X-linked recessive diseases?

The mother's ability to pass the disease allele. Signup and view all the answers

What does the summit recommend regarding germline gene editing at the current time?

A rigorous pathway should be defined before proceeding. Signup and view all the answers

What is the general stance of the scientific community on somatic gene editing?

It is a promising approach to treating genetic diseases. Signup and view all the answers

What kind of therapy did Layla Richards receive for her leukemia?

UCART19 cells via CAR-T cell therapy Signup and view all the answers

What was a notable outcome of the treatment received by Layla Richards?

The cancer cells completely disappeared. Signup and view all the answers

Which of the following statements about the current state of somatic genetic modification is true?

Clinical trials in this field are few but have started. Signup and view all the answers

What is the primary function of the CAR-T cell therapy in treating cancer?

It modifies T lymphocytes to attack tumor cells. Signup and view all the answers

What was the initial condition of Layla Richards at 14 weeks of age?

She was diagnosed with aggressive leukemia. Signup and view all the answers

How does the summit describe the current understanding of the scientific and technical requirements for germline gene editing?

Too uncertain to permit clinical trials at this time. Signup and view all the answers

What is a key characteristic of UCART19 cells as described in the content?

They are an experimental treatment based on TALENs. Signup and view all the answers

Study Notes

Unit 4: Gene Editing. CRISPR

Gene editing modifies the genome, contexts (epigenetic marks), or results (transcripts) using endonucleases, enzymes that cut DNA.

Previous Technology: Recombinant DNA

Recombinant DNA technology involves inserting a gene of interest into a plasmid, placing the plasmid into a bacterium, and growing the bacterium in a culture to create copies of the gene.
The resulting protein can be harvested and used in research and certain applications (e.g., pest resistance crops, treating diseases).

Genetic Editing

Recombinant DNA is a previous technology compared to gene editing.
Gene editing, using newer techniques like CRISPR, has greater precision and lower costs than recombinant DNA techniques.
Inaccuracies, ineffectiveness, and applicability factors are potential problems in gene editing.

Gene Editing Tools

ZFNs (Zinc Finger Nucleases): High cost, complex operation, and operating problems.
TALENs (Transcription Activator-Like Effector Nucleases): More challenging and expensive compared to CRISPR.
CRISPR-Cas: Easier and more affordable technology that has revolutionized this field.

CRISPR-Cas

A natural defense system in bacteria and archaea against viruses.
CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats): Repeating DNA sequences separated by short segments of foreign DNA, important component of the system.
Cas (CRISPR-associated): Proteins that form a complex with crRNA and work together to cut foreign DNA at specific locations.

The Natural System (CRISPR-Cas)

A 3-step process for defending against viruses in prokaryotic cells:
- Acquisition: Foreign viral DNA is incorporated into CRISPR locus.
- Expression: CRISPR RNA (crRNA) is processed from the CRISPR locus and forms a complex with Cas proteins.
- Interference: The crRNA-Cas complex targets and degrades matching viral DNA, preventing infection.

CRISPR as a Gene Editing Tool

Timeline of significant milestones in CRISPR development, research, and application.
In 1987, CRISPR was first reported.
Between 2000 and 2014, discoveries about CRISPR-Cas systems and their applications in various fields emerged.
In 2012, Charpentier and Doudna revealed the mechanism of CRISPR/Cas9 and demonstrated its potential for gene editing.
The Nobel Prize in Chemistry 2020 was granted to Emmanuelle Charpentier and Jennifer A. Doudna for discovering this method.

DNA Repair Mechanisms

Non-homologous end joining (NHEJ): A fast repair mechanism, but prone to errors like insertions or deletions.
Homology-directed repair (HDR): A more precise repair pathway where a template is used to repair the DNA break.

###Applications of CRISPR

Gene therapy has promising potential
Applications in medicine, including drug development, animal models, gene surgery, diagnostics, and materials science, as well as biotechnology.
Uses in agriculture (e.g., crops resistant to diseases and environmental factors).
Germline genetic modification affects reproductive cells (sperm and egg) or early embryonic development and results in heritable changes to future generations.

Medical Applications

Somatic genetic modification targets non-reproductive cells (like stem cells) for treating diseases such as cancer and genetic disorders.
Germline modification targets reproductive cells and early embryos.

CRISPR Case Examples

Layla Richards received treatment for leukemia using CAR-T cell therapy which was based on a newer gene editing technology (TALENs).
A woman with sickle cell disease was cured using CRISPR gene editing to change a specific gene.

Risks and Ethical Considerations Associated with CRISPR

Off-target effects
Mosaicism
Risks associated with genome editing, including potential for unintended mutations and safety/ethical issues.
Ethical issues related to using CRISPR on human germline cells for modifications that will affect future generations of individuals.
Unfavorable benefit-risk balance, and falsified ethical documents.
Potential risks to the ecosystem, food chain, and appearance of new pests.
The possibility of the spread of mutated guide RNAs, and dual use technology of the method itself

CRISPR-Edited Plants

Specific examples of plant varieties or crops altered to be resistant to environmental stressors or diseases.

Crops Resistant to Diseases

Specific examples of crop varieties or rice that have been made resistant to disease using CRISPR/Cas9.
Some crops have been genetically modified to resist diseases (e.g., rice with enhanced disease resistance).

Transgenic Organisms vs. Gene Editing

Differentiate between using foreign genes (transgenic) vs. making small alterations in existing genes (gene editing).
How they apply to organisms.

EU Regulations

Restrictions on the use of CRISPR in plant gene editing.
Research in the EU regarding genome editing.

Safety and Additional Notes

Safety and ethical aspects of CRISPR.
Need for lengthy analysis of characteristics when testing and selecting gene-edited organisms.

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Description

Test your knowledge on the outcomes, risks, and ethical concerns surrounding germinal genetic modification, particularly in relation to the Jiankui case. This quiz covers key concepts in gene editing technologies, DNA repair mechanisms, and significant events in the field of genetics. Dive deep into the implications of these advancements and their ethical considerations.