Housekeeping:
Participants are asked to turn off cell phones to avoid interruptions, but are welcome to leave them on to tweet questions using the hashtag globalhealth.

Speaker Introductions:
Jennifer Doudna, from the University of California, Berkeley, is a popular scientist known for her work on CRISPR technology. Craig Mello, a Nobel Prize winner, has done notable research in biology, including RNA interference, which is a method of silencing genes.

Genetics Overview:
Craig Mello suggested starting the discussion with a brief biology overview to provide context for the topic of gene rewriting.

Introduction to Gene Expression:
Gene expression involves a simple four-letter alphabet of nucleotides: G, C, A, and T. These nucleotides form three-letter words that specify different amino acids. Amino acids serve as building blocks for proteins, with 20 different types of amino acids available. DNA, the genetic material, consists of billions of nucleotides and serves as the template for protein synthesis.

DNA Structure and Replication:
DNA pairs up with itself in a double helical structure. G pairs with C, and A pairs with T during DNA replication. This base pairing mechanism allows for accurate replication of genetic information.

RNA and Protein Synthesis:
Genes are transcribed into RNA, another type of nucleic acid, during gene expression. RNA is further processed into messenger RNA (mRNA). mRNA is decoded by ribosomes, reading the sequence of nucleotides in groups of three. Each three-letter code specifies a different amino acid. Ribosomes assemble amino acids into proteins, following the instructions encoded in the mRNA sequence.

Proteins:
Proteins are linear chains of amino acids with various chemical properties. Proteins perform various functions within cells, including structural support, enzymatic reactions, and cellular communication.

Terminology Clarification:
Transcription: Copying DNA into RNA to create a template for protein synthesis. Expression: Building or activating a protein based on genetic instructions. Protein: A molecule composed of amino acids that performs various functions within cells.

RNA’s Significance:
RNA, a molecule traditionally considered less interesting than DNA and proteins, has recently gained recognition for its critical role in cells and human health. Scientists have discovered the tremendous diversity of RNA molecules and their functions, spanning from genetic regulation to immune responses.

RNA’s Role as an Intermediary:
RNA serves as an intermediary molecule between DNA and proteins. By manipulating RNA, it is possible to influence protein production and thereby affect various cellular processes.

Microbiome’s Importance:
Organisms, including humans, are not standalone entities but colonies of diverse microorganisms. The microbiome, consisting of bacteria and other microorganisms, plays a vital role in our survival and well-being.

Information Exchange:
Nucleic acid sequences, such as DNA and RNA, are constantly exchanged in the environment through bacteria and viruses. This exchange can be beneficial, providing resistance to infections, or harmful, causing illnesses.

Cellular Defense Mechanisms:
Cells possess defense mechanisms to combat foreign nucleic acids, such as viral infections. These mechanisms include proteins that act as search engines, using RNA queries to identify and neutralize invading nucleic acids.

Summary:
CRISPR is a groundbreaking technology that harnesses the cell’s natural gene editing machinery to precisely target and modify DNA sequences. The discovery of RNA interference (RNAi) in 1998 by Andrew Fire and Craig Mello paved the way for artificial gene regulation by introducing queries into the cell’s search engines for genetic information. RNAi involves blocking gene expression by interfering with the translation of messenger RNA into proteins. CRISPR technology utilizes a molecular scalpel-like approach, allowing precise identification and modification of specific DNA sequences in the genome. Unlike traditional gene manipulation techniques, CRISPR enables targeted changes to the DNA without affecting other regions, making it a powerful tool for correcting genetic defects and studying gene function.

CRISPR Mechanism:
CRISPR systems are derived from bacterial defense mechanisms against viruses. Bacteria acquire DNA sequences from invading viruses and use them to create RNA molecules that can search for matching viral sequences. When a match is found, proteins engage with the viral DNA, leading to its destruction. CRISPR-Cas systems, adapted from this natural mechanism, allow for precise targeting and editing of DNA in various organisms.

Applications of CRISPR:
CRISPR technology has revolutionized genetic research, enabling precise gene editing, gene regulation, and genetic disease modeling. CRISPR-based therapies hold promise for treating genetic disorders by correcting disease-causing mutations. CRISPR’s applications extend to agriculture, where it can be used to create crops with improved traits, such as resistance to pests and diseases. CRISPR has opened up new avenues for studying gene function and understanding the genetic basis of various diseases.

Challenges and Ethical Considerations:
CRISPR technology, while powerful, raises ethical concerns regarding its potential misuse and unintended consequences. Off-target effects and unintended genetic changes remain a challenge that requires careful consideration and further research. The ethical implications of CRISPR-based germline editing, which can introduce permanent changes that can be passed on to future generations, need to be carefully addressed. Responsible and transparent use of CRISPR technology is crucial to ensure its benefits are harnessed while minimizing potential risks.

Introduction:
The CRISPR-Cas9 system is a powerful gene editing tool that has revolutionized the field of biology. This system allows scientists to make precise changes to the DNA of living organisms, offering potential treatments for various diseases and genetic disorders.

Mechanism of Action:
CRISPR-Cas9 works by searching for specific DNA sequences and making precise cuts at those locations. The enzyme Cas9 is guided to the target DNA sequence by a short RNA molecule called guide RNA. Once Cas9 binds to the target DNA, it unwinds the DNA and cuts both strands.

Programmable Nature:
The CRISPR-Cas9 system is programmable, meaning scientists can design guide RNAs to target specific DNA sequences. This allows for precise and targeted gene editing.

Applications in Human Health:
CRISPR-Cas9 has potential applications in treating various human diseases, including genetic disorders, cancer, and infectious diseases. By targeting and correcting defective genes, CRISPR-Cas9 can potentially cure or mitigate these diseases.

Simplicity and Accessibility:
CRISPR-Cas9 is relatively easy to use, requiring only basic knowledge of molecular biology. This makes it accessible to a wide range of researchers and scientists.

Analogy for Understanding:
The CRISPR-Cas9 system can be compared to a word processor, where the DNA is the book, the guide RNA is the search function, and Cas9 is the cut and paste function. This analogy helps illustrate the simplicity and programmability of the CRISPR-Cas9 system.

Potential for Treating Diseases:
CRISPR-Cas9 offers great potential for treating a wide range of diseases, including genetic disorders, cancer, and infectious diseases, by precisely targeting and correcting defective genes.

Overview:
The discussion focuses on the challenges and gaps in knowledge in applying genetic tools, such as RNA interference, to therapeutics. The discovery of new knowledge often leads to more questions, creating new gaps in understanding.

Genome Sequencing and Gaps in Knowledge:
Sequencing genomes, like the human genome, generates new knowledge but also raises new questions. Understanding genetic lesions or polymorphisms linked to diseases does not directly translate to therapies.

Personal Gaps in Knowledge and Genetic Testing:
Individuals may have genetic information about diseases but lack therapies to address them. Health checkups and cancer diagnoses often reveal new genetic information, adding to personal burdens. Lack of genetic tests for certain diseases, such as prostate cancer, further complicates understanding genetic predispositions.

Conclusion:
The gaps in knowledge and challenges in applying genetic tools to therapeutics require further research and advancements to translate genetic information into effective treatments.

CRISPR and Human Genetics:
CRISPR technology enables researchers to study human genetic disorders in model organisms, allowing for more effective and precise investigations. By incorporating disease-causing genetic lesions into animal models, scientists can gain insights into the mechanisms of the disease and test potential therapeutic approaches.

Reverse Flow of Information:
Traditionally, research involved modeling biology in model organisms and extrapolating information to humans. With CRISPR, scientists can now take genetic information from humans and model it in organisms, leading to a more targeted and accurate understanding of human biology.

Gene Therapy and CRISPR:
Earlier attempts at gene therapy faced challenges in delivering and controlling the expression of normal gene copies. CRISPR provides a precise tool that allows scientists to target specific genetic mutations and replace them with normal gene sequences, potentially correcting genetic disorders.

Therapeutic Potential of CRISPR:
CRISPR has great therapeutic potential for diseases involving cells that can be manipulated in the laboratory. Stem cells from patients with genetic disorders can be repaired and reintroduced to provide the necessary function. Challenges arise in delivering CRISPR-based therapies to specific tissues or throughout the entire body, particularly in complex disorders like muscular dystrophy or Down syndrome.

Germline Editing:
CRISPR technology raises ethical concerns due to its ability to edit the human germline, affecting future generations. Editing the germline allows for the manipulation of genetic traits in animals, including humans, which has implications for breeding and genetic engineering.

Ethical Implications of Germline Modification:
CRISPR enables rapid genetic changes in organisms, including their germline, raising ethical concerns. Modifications to sperm or eggs could have unintended consequences due to limited understanding of genomic information. The potential for unintended effects and the difficulty in predicting long-term outcomes pose challenges.

Drawing the Line:
Questions arise about where to draw the line in terms of acceptable germline modifications. Correcting mutations causing genetic diseases is generally considered acceptable, but enhancements for traits like eye color raise ethical concerns.

Need for Education and Conversation:
Jennifer Doudna emphasizes the need for educating the public about CRISPR technology and fostering conversations about the bioethical implications. UC Berkeley and UC San Francisco’s Innovative Genomics Initiative aims to educate people and promote discussions on bioethics surrounding CRISPR.

Curing Cancer with Genetic Engineering:
Craig Mello acknowledges the existence of successful cancer therapies, but cautions against overpromising cures. Scientists are continually exploring genetic engineering approaches to cancer treatment, but progress is ongoing.

Immune System and Cancer:
A new form of cancer treatment called immunotherapy involves modifying a patient’s own immune system to recognize and attack cancer cells, resulting in promising outcomes like complete remission in inoperable brain tumors.

CRISPR and Cancer:
The precise nature of CRISPR technology offers the potential to engineer the immune system to more effectively target and kill cancer cells.

Genetic Diseases:
There’s a distinction between genetic diseases caused by inherited genetic defects and those caused by genetic machinery malfunctions within cells. For instance, cancer often occurs due to changes in gene functioning over time, not necessarily inherited genetic defects.

Bone Marrow Stem Cell Therapy:
Clinical trials are underway to use CRISPR to modify bone marrow stem cells, which can then be reintroduced to the patient’s body to combat HIV infection. This approach relies on the positive selective pressure to populate the immune system with cells that are resistant to HIV.

Basic Research and Technological Innovations:
Scientific advancements and technologies often emerge from curiosity-driven research, where scientists investigate fundamental biological mechanisms without a specific therapeutic goal in mind. Examples include the polymerase chain reaction (PCR) and green fluorescent protein (GFP), which were initially discovered through curiosity-driven research and later harnessed as valuable technologies.

Importance of Fundamental Research:
Fundamental research in biology, such as understanding the basics of the genetic code and protein structure, provides crucial insights and foundations for technological breakthroughs. The genetic code, for instance, is conserved across organisms like bacteria and humans, enabling researchers to study fundamental genetic processes using model organisms.

Protein Folding and Complexity:
Predicting how a protein will fold from a primary sequence of amino acids remains a significant challenge due to the intricate chemistry and emergent properties associated with protein folding.

The Importance of Basic Research:
Basic research can lead to significant breakthroughs in applied research, such as the development of the polio vaccine. Applied research often leads to incremental improvements, while basic research can result in quantum leaps forward.

RNA Interference as a Multi-Billion Dollar Industry:
RNA interference is a powerful genetic tool that has led to the development of a multi-billion dollar industry. Guide RNAs, which are essential for RNA interference, can be ordered online and delivered quickly. The ability to easily knock out genes in the human genome has led to numerous applications in research and medicine.

Intellectual Property Issues:
There are ongoing debates about who owns the intellectual property rights to RNA interference technology. Jennifer Doudna and her colleagues filed some of the original intellectual property claims, but other researchers are also developing new and improved methods. The sorting out of intellectual property rights is beneficial for the economy as it leads to startups and commercialization of the technology.