Sunday, 12 March 2017

Darwin Day Lecture: Gene Editing with CRISPR

The regular Central Manchester monthly meeting was replaced by
a celebratory day at the Manchester Conference Centre to mark Darwin’s birthday on 12 February.   The event started at 1pm and was attended by 90 visitors.  There were a range of exhibits from Population Matters, RSPB, Amnesty International, thINK the book, Friends of the Earth, Barton Theatre Company and Peace Mala from a local primary school.  At 3.00pm the Greater Manchester Humanist Choir sung 'Seikilos Epitaph' and 'Darwin's Revolution' both arranged by former Musical Director Karl Kramer.  This was followed by a talk by Professor Matthew Cobb from the Life Sciences Department at the University of Manchester on "The Brave New World of CRISPR Gene Editing". 

Matthew introduced the topic by saying that he does not think that governments and institutions understand the importance and implications of recent developments in gene editing technology and the CRISPR technique which enables the precise editing of genes in virtually any organism, including humans.  CRISPR stands for ‘clustered regularly interspaced short palindromic repeats’ which are segments of DNA containing short, repetitive base sequences, that  are the same in both directions.  Each repetition is followed by short segments of spacer DNA from previous exposures to foreign DNA (e.g., a virus or plasmid). The cell's genome can be cut at a desired location, allowing existing genes to be removed and/or new ones added to effect improvements in that DNA.  

Matthew explained that the ability to alter genetic material of organisms was developed in the 1970s  but involved molecular tinkering over long periods.  With the development of the CRISPR technique in 2013, modifications that took 18 months are now being done in 6 weeks.  Two sources claim to have devised it: Emmanuelle Charpentier and Jennifer Doudna from Berkeley, and George Church and Feng Zhang from Boston Broad Institute.  CRISPR genome editing has many applications in the areas of human gene therapy, somatic therapy, agriculture, and vector control.

The application to human gene therapy enables changes in human genes that alter the genetic make-up of the next generation.  There is a general reluctance to allow this on ethical grounds: CRISPR gene therapy is not legal in the UK, Australia or Canada.  In the USA the technique cannot be applied using federal money, but is permitted using private funds.  

CRISPR techniques can be applied in the treatment of illnesses without altering the genetic make up of the next generation by editing the body’s somatic cells.  This type of intervention is therefore not subject to the same ethical concerns as genetic manipulation of human embryos.  CRISPR therapies for blood based diseases, leukaemia, HIV and sickle cell anaemia may soon be trialled and the technique shows great promise as a treatment for Duchenne Muscular Dystrophy.  

CRISPR is also being used in agricultural research exploring its application to boosting crop resistance to pests thereby reducing the toll of livestock disease.

As to vector control, CRISPR could be used to introduce new genetic material into organisms that transmit disease, such as the malaria carrying mosquito, that both makes females sterile and accelerates its spread throughout the whole population, so as to effectively eliminate that population  in a few generations.

Work is currently being undertaken at Imperial College London on this.  The scientific community is proceeding cautiously in this area given the potential impact on ecosystems.     
Matthew concluded his presentation by talking about the ethics of using CRISPR.  He posed the question of whether it is ethical to limit its use and thus its potential in fighting disease, illness and poverty.  He was clear that its further application should be properly regulated.     

In the question and answer session, when asked if CRISPR could assist with curing dementia or cancer Matthew responded that the application of CRISPR to combat a disease will depend on whether the disease or condition has an identifiable genetic sequence that can be easily disabled.   Dementia and cancer do not have identifiable genetic sequences.   

When asked if CRISPR could be used to regrow organs, Matthew answered that this was possible in theory by using stem cells that can be grown into any organ.

Matthew thought the application of the CRISPR system will need a political system to buy-in to it and to enforce it and that the short-termism associated with most political systems makes this problematic.  

Matthew recommended the following sources on CRISPR: Ted Talks on CRISPR on YouTube, “CRISPR Democracy: Gene Editing and the Need for Inclusive Deliberation” in Issues in Science and Technology, Volume XXXII Issue 1 Fall 2015,  “CRISPR-Cas9 ("Mr. Sandman" Parody) A Capella Science” on YouTube,  “Life’s Greatest Secret” by Matthew Cobb.

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