If we want to understand how the brain creates memories, and how genetic disorders distort the brain’s machinery, then the fragile X gene is an ideal place to start. That’s why the Stephen T. Warren Memorial Symposium, taking place November 28-29 at Emory, will be a significant event for those interested in neuroscience and genetics.
Stephen T. Warren, 1953-2021
Warren, the founding chair of Emory’s Department of Human Genetics, led an international team that discovered Read more
At a time when COVID-19 appears to be receding in much of Georgia, it’s worth revisiting the start of the pandemic in early 2020. Emory virologist Anne Piantadosi and colleagues have a paper in Viral Evolution on the earliest SARS-CoV-2 genetic sequences detected in Georgia.
Analyzing relationships between those virus sequences and samples from other states and countries can give us an idea about where the first COVID-19 infections in Georgia came from. We can draw Read more
Young, who is world-renowned for his work on the role of neuropeptides in regulating social behavior, uses voles to investigate the neurobiological and genetic mechanisms underlying social behavior. Using the monogamous prairie vole (vs. the promiscuous meadow vole) as a model organism, Young and his research team identified the oxytocin and vasopressin receptors as key mediators of social bonding and attachment. In addition, they are examining the consequences of social bond disruption as a model of social loss-induced depression.
This work has important implications for developing novel treatment strategies for psychiatric disorders associated with social cognitive deficits, including autism spectrum disorders and schizophrenia.
An Emory project studying schizophrenia genetics is a good example of how geneticists are shifting from examining small, common mutations to “rare variants” when studying complex diseases.
From studies of twins, doctors have known for a long time that heredity plays a big role in causing schizophrenia. But dissecting out which genes are the most important has been a challenge.
Threelandmarkstudies on schizophrenia genetics published this summer illustrate the limitations of “genome wide association” studies. New York Times science reporter Nicholas Wade summarized the results in this way:
“The principal news from the three studies is that schizophrenia is caused by a very large number of errant genes, not a manageable and meaningful handful.”
The limitations from this type of study comes from the type of markers geneticists are looking at, says Steve Warren, chair of the human genetics department at Emory.
Genome wide association studies usually follow SNPs — single nucleotide polymorphisms. This is a one-letter change somewhere in the genetic code that is found in a fraction of the population. It’s not a big change in the genome, and in many cases, it will have a small effect on disease risk.
Researchers looking for the genes behind complex diseases such as schizophrenia and autism are starting to shift their efforts away from genome wide association studies, Warren says.
Think of a SNP like a misspelling of a word in a certain place in a book, he says. In contrast, the “rare variants” geneticists are starting to study more intensively are more like printers’ errors or missing pages. The rapid sequencing technology that allows scientists to investigate these changes easily is just now coming on line, he says.
One example of these rare variants is DiGeorge syndrome, a deletion that gets rid of dozens of genes on one copy of chromosome 22. Children who have this chromosomal alteration often have anatomical changes to their heart and palate. But it also substantially increases the risk of schizophrenia – to about 25% lifetime risk. That’s a lot more than any of the SNPs identified this summer.
Working with several Emory colleagues, researcher Brad Pearce is planning to examine the genes missing in DiGeorge syndrome in several groups of patients: people with DiGeorge, patients with “typical” schizophrenia and people at high risk of developing schizophrenia.
An article in this spring’s Emory Health describes genetic research on autism. Several of the researchers mentioned there, such as geneticist Joe Cubells and psychiatrist Opal Ousley, are involved in this schizophrenia project as well, because deletions on chromosome 22 also lead to an increased risk of autism.