BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: gene research

What does the future hold for CRISPR-Cas9?

Genome editing, or the technologies in which scientists can change the DNA of an organism, is on the rise, especially with its latest development, CRISPR-Cas9, the most efficient method of all of the methods to edit DNA.

Like many other discoveries in science, CRISPR-Cas9 was discovered through nature. Scientists learned that certain bacteria capture snippets of DNA from invading viruses, making DNA segments called CRISPR arrays, helping them remember the virus to prepare for future invasions of that virus. When they are confronted with that virus again, RNA segments from the CRISPR arrays are created which target the DNA of the virus, causing the enzyme Cas9 to cut the virus’ DNA apart, which would destroy the virus.

 

We use the same method in genome editing with CRISPR-Cas9 by creating RNA that binds to a specific sequence in a DNA strand and the Cas9, causing the Cas9 to cut the DNA at that specific sequence. Once this is done, the scientists create a sequence to replace the one that was cut to get the desired genome.

This technology is most prominently used to attempt to treat diseases, where the somatic cells’ genomes are altered which affect tissues, as well as prevent genetic diseases where the sperm or egg’s genome is changed. However, the latter causes some serious ethical concerns of whether we should use this technology to enhance human traits. But this begs the question that if we start using it more and more to prevent genetic diseases, will this open the door for it to be used in new ways?

Does long-term endurance training impact muscle epigenetics?

800px-Nucleosome_1KX5_2

 

Epigenetics translates to “above” or “on top of” genetics. To be more specific, Epigenetics is the study of how modification of gene expression can cause changes in many organisms.

A new study from Karolinska Institutet in Sweden explores the theory that long-term endurance training alters the epigenetic pattern in the human skeletal muscle. The team that conducted the research also explored strong links between these altered epigenetic patterns and the activity in genes controlling improved metabolism and inflammation.

The study was conducted using 23 young and healthy men and women. The men and woman would perform one-legged cycling – where the untrained leg would be the control of the experiment. Four times a week and over the course of three months, the volunteers would participate in a 45 minute training session. Though skeletal muscle biopsies, supervisors would measure their markers for skeletal muscle metabolism, methylation status of 480,000 sites in the genome, and activity of over 20,000 genes.

At the end of the study, the researchers concluded that there was a strong relationship between epigenetic methylation and the change in activity of 4000 genes in total. Epigenetic methylation is defined as the “addition of a methyl group to a substrate or the substitution of an atom or group by a methyl group. ” Moreover, it was determined that methylation levels increased when involved in skeletal muscle adaptation and the metabolism of carbohydrates. However, methylation levels decreased in regions associated to inflammation.

Furthermore, Carl Johan Sundberg found that “endurance training in a coordinated fashion affects thousands of DNA methylation sites and genes associated to improvement in muscle function and health.” He believes that this determination could be vital to understanding the treatment of diabetes and cardiovascular disease as well as how to properly maintain good muscle function throughout life.

This article relates very much to our work in class as we learn the Molecular Genetics Unit. It connects because we are learning what happens when mutations occur in one’s genome and the impacts those mutations have on someone. For example, cancer is one of the most researched and explored topics in regard to how modification of gene expression alters organisms. Oncogenes and Tumor suppressor genes have vital impacts on cellular division, changes to cellular function, and the growth of tumors.

Could There be Good Gene Mutations?

Is there an epic battle occurring within our bodies right now? The classic battle royale between good and bad? I suppose in the body’s case the fight between good and bad genes.  There is a new field in medical research in which researchers are on the quest to find good gene mutations that fight against the disease causing mutations.  One individual, Doug Whitney, sparked the interest of a few doctors because he has fought his genetic odds to be health at 65 years old.  Whitney has a gene mutation, presenilin, that causes early onset Alzheimer’s disease in those who has inherited it. Whitney’s mother and 9 out of his 13 siblings were killed by this mutation and so Whitney’s fate seemed to be sealed.  However when Whitney reached his 40s and 50s having no symptoms he assumed he did not have the gene.  At 62 years old, Whitney, decided he would get a gene test.  He did have the gene.  This was an anomaly, He was doomed to have early onset Alzheimer’s Disease but had absolutely no symptoms. Although Whitney still have changes of getting Alzhiemers but the effects of his bad gene have been greatly delayed by another gene in Whitney’s DNA.  Whitney joined a study at Washington University in St. Louis led by Doctor Randall Bateman which recruited people with the early onset Alzheimer’s disease gene. This attracted the attention of Doctor Eric E. Schadt and Doctor Stephen H. Friend.  Doctor Schadt said that searching for good genes that protect against bad gene mutations is completely turning genetic research on its head.  Researchers have found gene mutations that partially protect diseases like osteoporosis, Type 2 diabetes, heart disease, and Alzheimer’s.  These good gene mutation’s partial protect have help to develop drugs to help fight certain diseases. Finding good gene mutations are substantially more difficult to find than bad genes, but the search has gotten a little easier with fast and inexpensive methods of sequencing DNA. Doctor Schadt and Doctor Friend decided to start the Resilience Project and search for good gene mutations that counteract bad gene mutations to help develop new break though treatments and drugs. They have contacted the researchers at Washington University, the research that Whitney is currently participating in.

For more information:

Article from NYT

Prokaryotic positive genetic influences

Genetics used for intrusion protection

About genetic testing

 

Incredible New Gene-Searching Software

MIKI Yoshihito
http://www.fotopedia.com/items/flickr-2559447601

Joseph T. Glessner, of the Center for Applied Genomics at the Children’s Hospital in Philadelphia recently invented a new software tool that will revolutionize accuracy in genetic disease studies. The software called ParseCNV is an algorithm that “detects copy number variation associations with higher levels of  accuracy than that available in existing software,” says Mr. Glessner. This incredible software automatically corrects for variations in the length of deleted or duplicated DNA sequences from one individual to another and produces high quality, replicable results for researchers studying genetic diseases.

CNV stands for copy number variations which are sequences of DNA, ranging from 1000 to millions of nucleotide bases, which may be deleted or duplicated. These CNV’s are very difficult to find because they are so rare but so important in the discovery of genetic diseases. Previous methods to find the link between CNV’s and disease involved individual case-control studies, in which diseased DNA is compared to healthy DNA. This method does not work accurately because different people have different CNV’s which can effect the outcome of the diagnosis.

ParseCNV is incredible in that it can account for and adjust to so many differences in genes and has so much versatility in that it is applicable to family studies and quantitative analyses of continuous traits. I am really looking forward to seeing the future of this amazing algorithm and its contributions to genetic research.

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