#editing – BioQuakes

Do you know anyone who has needed an organ transplant? Hopefully, the answer is no. However, many medical dramas on television have shown us the awful process patients go through when waiting on a transplant list for a heart, lung, kidney, etc.

For years, scientists have experienced many trials and errors. They explored pig parts and ways to supplement them as human organs. However, a huge advancement in gene editing has just reinstated hope for many suffering patients. On March 16th, Richard Slayman received a pig kidney. He had type two diabetes and had been on dialysis. He had a transplant several years ago, but the organ showed signs of failure. Doctor Winfred Williams explained that Slay would not have survived if he had to wait another five years for a human kidney transplant.

Eventually, the idea was proposed for Slayman to receive a genetically engineered pig kidney from eGenesis, a biotechnology company. Their goal is to generate human-compatible organs that can be used in transplants. In Slayman’s case, this kidney had been genetically altered 69 times using the CRISPR-Cas9 gene editing system, which allows certain parts of a genome to be removed or even added. Slayman’s new kidney was made suitable for him in a very meticulous way. Firstly, three genes that are typically found in pigs that attack human immune systems were removed. These were genes that code for the synthesis of certain carbohydrates. Additionally, seven human genes were added to the genome that prevent an immune response that may lead to transplant rejection. Certain pig viruses were also removed as they pose a harm to humans.

This is very relevant to one of our last AP Biology units. We just learned about mRNA processing. This step occurs following mRNA transciption, with the goal of making certain proteins. After the nitrogenous bases are transcrribed from template DNA, the mRNA is processed in several ways. A Guanine cap is added to the front of the strand and a Poly-A tail is added to the end. Additionally, parts of the mRNA are cut out. In CRISPR editing, this same process is done by scientists artificially, rather than our natural processes. The parts of mRNA that are cut out that will not make a protein are called introns, while the kept parts of mRNA are called exons. mRNA splicing can also take place where different combinations of bases are organized to make certain amino acid chains.

This new advancement will not only help patients receive new organ quicker, but it is the doctors’ hope that this will solve a larger cultural issue, in that ethnic minorities often struggle to receive organ transplants. This new process will hopefully benefit the healthcare system both medically and culturally.

What are the most annoying things on Earth? Why, mosquitoes of course. They bite you and their bites are extremely irritating. Mosquitoes also carry life-threatening viruses, such as Malaria. However, scientists have come up with a way to get rid of mosquitoes carrying Malaria with the help of gene drives.

A gene drive is a self-generating “cut-and-paste system” that can sterilize mosquitoes. Well how do gene drives work? They operate using CRISPR/Cas9, precision molecular scissors that cut DNA. Scientists used CRISPR/Cas9 to disrupt the genes that are active in mosquito ovaries. If a female mosquito is missing one of these genes, they become sterile. Gene drives insert themselves into a target gene to assimilate every unaltered gene they pass. They break normal inheritance rules by being able to pass themselves into over 50% of an altered animal’s offspring.

The first gene drive that was made stopped mosquitoes from transmitting Malaria. This new gene drive would eliminate Malaria-carrying mosquitoes in the future by making the females sterile, unable to reproduce. This gene drive is not 100% perfect yet, but scientists are hoping to perfect it soon to be able to release it. They hope that this gene drive will be able to control different insect populations, not only mosquitoes.

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BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: #editing

CRISPR Gene Editing Provides Hope for Patients on Transplant List

Harmless Mosquitoes…Yes Please

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