CHIMERAS

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A mathematician by training, I discovered genetics in 2006 and never turned back. This blog was born to share all the fascinating things I learn about genes and DNA through my current research on viral genetics and HIV.

EE Giorgi
153 posts

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  • April 20, 2014
  • 09:31 AM
  • 82 views

Was Lamarck right after all? A look at epigenetic inheritance

by EE Giorgi in CHIMERAS

Myths © EEGFrom the Wikipedia definition of epigenetics: "In biology, and specifically genetics, epigenetics is the study of heritable changes in gene activity that are not caused by changes in the DNA sequence."Wait a minute... how can we inherit anything that's not encoded in the DNA? All the information we inherit from our parents is coded in the DNA ... Right?That's correct. However, there's something very important that goes hand in hand with the information contained in the genes: how and........ Read more »

  • April 10, 2014
  • 09:54 AM
  • 108 views

Aluminum adjuvants in vaccines: are they safe?

by EE Giorgi in CHIMERAS

Multnomah Falls, © EEGDisclaimer: I work on HIV vaccine design and I'm quite proud of it. I know that for three million HIV-positive kids in Africa, a vaccine is the only hope they have to grow into adulthood. So, when people tell me that vaccines are bad I cringe. Infant mortality rates have dropped since vaccinations have been introduced. We live longer, healthier lives thanks to vaccines. Diseases like polio can paralyze and kill, yet they are no longer a concern for children in the western ........ Read more »

  • March 30, 2014
  • 11:26 AM
  • 79 views

What do one trillion different scents smell like?

by EE Giorgi in CHIMERAS

I've been really happy with the comments on my upcoming detective thriller CHIMERAS. The book will be released in two weeks, but I've already heard back from some early readers (and yes, I'm still offering free ARC's, see details here), and many have praised Track's sensitivity to smells. Apparently, it's a trait many relate to and yet you don't find so often in fiction. Most of our memories are stored as images. So, even when we write, we tend to over-emphasize visual descriptions and forget al........ Read more »

Bushdid C, Magnasco MO, Vosshall LB, & Keller A. (2014) Humans can discriminate more than 1 trillion olfactory stimuli. Science (New York, N.Y.), 343(6177), 1370-2. PMID: 24653035  

Vanderhaeghen P, Schurmans S, Vassart G, & Parmentier M. (1993) Olfactory receptors are displayed on dog mature sperm cells. The Journal of cell biology, 123(6 Pt 1), 1441-52. PMID: 8253843  

  • March 21, 2014
  • 09:46 AM
  • 151 views

I carry my son's DNA: a look at microchimerism and its effects

by EE Giorgi in CHIMERAS

To celebrate the upcoming release of my detective thriller CHIMERAS, the next few Research Blogging posts will be dedicated to the different forms of chimerism. I'm sure you are all familiar with dispermic chimeras, which occur when two fertilized eggs fuse together shortly after conception. The result is one individual with two sets of genetically distinct cells. Have you ever heard of microchimerism, though?"Microchimerism refers to a small number of cells (or DNA) harbored by one individual t........ Read more »

Gammill HS, & Nelson JL. (2010) Naturally acquired microchimerism. The International journal of developmental biology, 54(2-3), 531-43. PMID: 19924635  

  • March 9, 2014
  • 11:42 AM
  • 122 views

Pregnancy and breast cancer risk: why age counts

by EE Giorgi in CHIMERAS

That an early pregnancy is protective against breast cancer is something I've known for ten years now. I remember one of my professors, back when I started studying genetics, saying: "Having a baby at 16 may ruin your life but it sure protects you from breast cancer." Today we know a lot more about the cellular and genetic mechanisms that a first pregnancy triggers in the body. And yet how these mechanisms turn out to be protective against breast cancer is still a mystery. "The ovarian hormones,........ Read more »

Medina D. (2005) Mammary developmental fate and breast cancer risk. Endocrine-related cancer, 12(3), 483-95. PMID: 16172188  

Meier-Abt F, & Bentires-Alj M. (2014) How pregnancy at early age protects against breast cancer. Trends in molecular medicine, 20(3), 143-153. PMID: 24355762  

  • February 21, 2014
  • 06:19 PM
  • 160 views

Converging genes reveal how plagues have shaped our genome

by EE Giorgi in CHIMERAS

Evolution is shaped by numerous factors. Selection is one of such factors, but, contrary to popular belief, it is not the only force acting on genomes. I cringe when I hear the expression "this gene has been selected for" because most of our alleles (we all have the same genes, but each gene can have different alleles across different ethnic groups/populations) haven't been selected at all. Things change even without any selection pressure from the environment, a phenomenon known as random drift........ Read more »

Hafid Laayounia,1, Marije Oostingb,c,1, Pierre Luisia, Mihai Ioanab,d, Santos Alonsoe, Isis Ricaño-Poncef, Gosia Trynkaf,2, Alexandra Zhernakovaf, Theo S. Plantingab, Shih-Chin Chengb, Jos W. M. van der Meerb, Radu Poppg, Ajit Soodh, B. K. Thelmai, Cisca. (2014) Convergent evolution in European and Rroma populations reveals pressure exerted by plague on Toll-like receptors. PNAS. DOI: 10.1073/pnas.1317723111  

  • February 16, 2014
  • 09:45 AM
  • 153 views

This season's flu helps inform next season's vaccine

by EE Giorgi in CHIMERAS

Last year I described the arm's race happening between virus and immune system during an HIV infection: as the immune system starts mounting its defense against the virus, the virus mutates trying to evade the attack. This is what pushes the virus to constantly evolve new strains, not just in HIV, but also in the flu virus, which evolves a new strain roughly every year. The HIV virus evolves within the same host to evade the host's immune response. On the other hand, the flu virus evolves more s........ Read more »

  • February 9, 2014
  • 09:52 AM
  • 182 views

Gene therapy for the heart

by EE Giorgi in CHIMERAS

My post today is about state-of-the-art gene therapy that delivers genes straight to heart, where the genes activate proteins critical in restoring cardiac tissue in people affected by heart failure. The technique, developed at the Cardiovascular Research Center at Icahn School of Medicine at Mount Sinai, is undergoing clinical trial.Cardiovascular disease is the leading cause of death worldwide. Heart failure--a condition by which the heart weakens and no longer pumps blood efficiently througho........ Read more »

  • February 2, 2014
  • 10:52 AM
  • 165 views

Computer generated viruses

by EE Giorgi in CHIMERAS

By "computer generated viruses" I don't mean bits of code that can harm your desktop. I mean actual viruses, objects that have the ability to infect and replicate, but were created in silico, by a computer algorithm. I know this is a concept that has the anti-vaxxers enraged, but in HIV it has become quite common to generate vaccine candidates through computer algorithms. Today I want to address two questions: why and how. Candidate vaccines are made from virus isolates: you take a real virus, m........ Read more »

Gaschen B, Taylor J, Yusim K, Foley B, Gao F, Lang D, Novitsky V, Haynes B, Hahn BH, Bhattacharya T.... (2002) Diversity considerations in HIV-1 vaccine selection. Science (New York, N.Y.), 296(5577), 2354-60. PMID: 12089434  

Santra S, Korber BT, Muldoon M, Barouch DH, Nabel GJ, Gao F, Hahn BH, Haynes BF, & Letvin NL. (2008) A centralized gene-based HIV-1 vaccine elicits broad cross-clade cellular immune responses in rhesus monkeys. Proceedings of the National Academy of Sciences of the United States of America, 105(30), 10489-94. PMID: 18650391  

  • January 13, 2014
  • 07:44 PM
  • 213 views

Mitochondria to the rescue

by EE Giorgi in CHIMERAS

Yes, I confess I'm quite fascinated by mitochondria. Not only their well functioning seems to be correlated to lifespan, like I discussed last time, but it's also implicated in cancer. Briefly, last post taught us that mitochondria provide energy to the cell by producing ATP through four different oxidative complexes. However, mitochondria's oxidative activity wanes with age. Researchers found one pathway in particular that is activated in low-fat diets and high-exercise regimens, which can reve........ Read more »

Gomes AP, Price NL, Ling AJ, Moslehi JJ, Montgomery MK, Rajman L, White JP, Teodoro JS, Wrann CD, Hubbard BP.... (2013) Declining NAD( ) Induces a Pseudohypoxic State Disrupting Nuclear-Mitochondrial Communication during Aging. Cell, 155(7), 1624-38. PMID: 24360282  

  • January 3, 2014
  • 08:05 PM
  • 265 views

The secret to a long life? Active mitochondria!

by EE Giorgi in CHIMERAS

For quite a while now we've known that if we want to live a long, healthy life, we must exercise regularly and be good about what we eat. Recent studies have added another piece to the equation: maintain mitochondrial function. Mitochondria are organelles found in every cell of our body. They hold a very important function: they provide energy to the cell. Most cellular processes take place using energy stored in a molecule called adenosine triphosphate, or ATP, and most of a cell's supply of AT........ Read more »

Lanza IR, & Nair KS. (2010) Mitochondrial function as a determinant of life span. Pflugers Archiv : European journal of physiology, 459(2), 277-89. PMID: 19756719  

Gomes AP, Price NL, Ling AJ, Moslehi JJ, Montgomery MK, Rajman L, White JP, Teodoro JS, Wrann CD, Hubbard BP.... (2013) Declining NAD( ) Induces a Pseudohypoxic State Disrupting Nuclear-Mitochondrial Communication during Aging. Cell, 155(7), 1624-38. PMID: 24360282  

  • December 14, 2013
  • 11:46 AM
  • 261 views

ASD and inflammation: more than just a correlation

by EE Giorgi in CHIMERAS

There has been a lot of speculation, lately, about vaccines possibly being harmful and, in particular, causing autism. You know I work on HIV vaccine design, so there's no need to say where I stand on the need of vaccinations. No link has been found between the incidence of autism and vaccination. Of course, medicine is not an exact science. Outliers will always exist. The U.S. seem to be a special case, as the vaccination schedule in this country requires a high number of vaccine doses, yet the........ Read more »

Hsiao EY, McBride SW, Chow J, Mazmanian SK, & Patterson PH. (2012) Modeling an autism risk factor in mice leads to permanent immune dysregulation. Proceedings of the National Academy of Sciences of the United States of America, 109(31), 12776-81. PMID: 22802640  

  • December 8, 2013
  • 11:25 AM
  • 282 views

Autism: not one disease but a spectrum of disorders; not one gene but a network of gene coexpressions.

by EE Giorgi in CHIMERAS

"Autism spectrum disorder (ASD) is a lifelong developmental condition that affects about 1 in 110 individuals, with onset before the age of three years. It is characterized by abnormalities in communication, impaired social function, repetitive behaviors and restricted interests [1]."ASD is more common among males than females, with a 4:1 male to female ratio. Numerous studies in the literature have shown evidence for a strong genetic component of autism, with a risk up to 25 times higher among ........ Read more »

Neelroop N. Parikshak, Rui Luo, Alice Zhang, Hyejung Won, Jennifer K. Lowe, Vijayendran Chandran, Steve Horvath, Daniel H. Geschwind. (2013) Integrative Functional Genomic Analyses Implicate Specific Molecular Pathways and Circuits in Autism. Cell. DOI: 10.1016/j.cell.2013.10.031  

A. Jeremy Willsey, Stephan J. Sanders, Mingfeng Li, Shan Dong, Andrew T. Tebbenkamp, Rebecca A. Muhle, Steven K. Reilly, Leon Lin, Sofia Fertuzinhos, Jeremy A. Miller, Michael T. Murtha, Candace Bichsel, Wei Niu, Justin Cotney, A. Gulhan Ercan-Sencicek, J. (2013) Coexpression Networks Implicate Human Midfetal Deep Cortical Projection Neurons in the Pathogenesis of Autism. Cell. DOI: 10.1016/j.cell.2013.10.020  

  • November 3, 2013
  • 10:31 AM
  • 250 views

A new viral vector raises hopes for an HIV vaccine

by EE Giorgi in CHIMERAS

Because I work on HIV vaccine research, I often talk about vaccines and HIV vaccine design in particular. So far, there have been several phase I HIV vaccine trials, but very few have made it into phase III. One such case was the STEP trial, which was abruptly halted in 2007 after preliminary results showed that not only the vaccine was not protecting people from getting the virus, but the rate of HIV infections was actually higher in the vaccinated subjects compared to the subjects that receive........ Read more »

Nilu Goonetilleke, Andrew J. McMichael. (2013) Antigen Processing Takes a New Direction. Science. DOI: 10.1126/science.1239649  

Scott G. Hansen, Jonah B. Sacha, Colette M. Hughes, Julia C. Ford, Benjamin J. Burwitz, Isabel Scholz, Roxanne M. Gilbride, Matthew S. Lewis, Awbrey N. Gilliam, Abigail B. Ventura, Daniel Malouli, Guangwu Xu, Rebecca Richards, Nathan Whizin, Jason S. Reed. (2013) Cytomegalovirus Vectors Violate CD8 T Cell Epitope Recognition Paradigms. Science. DOI: 10.1126/science.1237874  

  • October 5, 2013
  • 01:07 PM
  • 269 views

Sex Is Always Well Worth Its Two-Fold Cost

by EE Giorgi in CHIMERAS

Title borrowed from Feigel et al. [1].Sex is costly. In an asexual population, all individuals bear offsprings, resulting in a higher growth rate than in a sexual population (two-fold cost of sex). Finding a partner is risky, costly in terms of energy and resources, and it results in sexual selection which may not always favor survival. Finally, in sexual populations each individual passes only 50% of its genetic make-up to their offsprings and, furthermore, genetic recombination could break-up ........ Read more »

  • October 1, 2013
  • 07:15 AM
  • 332 views

Ms. Stick Insect

by EE Giorgi in CHIMERAS

Image credit: funkman.org.  You're looking at a stick insect, a critter I was quite used to growing up as my dad, an evolutionary biologist, used to grow them at home. I know, most households have cats, dogs, guinea pigs and rabbits; ours had cats, dogs, toads, fruit flies, and stick insects. :-)Children have a tendency to personify everything, animals in particular, so imagine my shock when my dad told me that stick insects are all... ladies. Yup. It's Ms. Stick Insect. And the reason why ........ Read more »

  • September 23, 2013
  • 09:24 AM
  • 346 views

Vaccines: what is the meaning of phase I, II and III?

by EE Giorgi in CHIMERAS

I'm often asked, "How long will it take to finally have an HIV vaccine? Are we close? What about this study that published good results on an HIV vaccine?" Right now, the HIV community is generally optimistic that we will indeed have an HIV vaccine within the next decade. This is based on the relatively recent discovery of new broadly neutralizing antibodies and the mildly positive results obtained by one of the five major efficacy trials, the RV144 Thai trial, which found a 31% reduction in HIV........ Read more »

Lawrence Corey, Gary J. Nabel, Carl Dieffenbach, Peter Gilbert, Barton F. Haynes, Margaret Johnston, James Kublin, H. Clifford Lane, Giuseppe Pantaleo, Louis J. Picker and Anthony S. Fauci. (2011) HIV-1 Vaccines and Adaptive Trial Designs. Sci Transl Med. DOI: 10.1126/scitranslmed.3001863  

  • September 15, 2013
  • 11:19 AM
  • 318 views

Bacteria to the rescue!

by EE Giorgi in CHIMERAS

Last month I talked about a cancer killing virus. Well, guess what comes next? A cancer killing bacterium, of course! :-) Our hero is once again, the one and only E. coli, a bacteria that normally resides in our guts and that is much beloved by experimentalists because it's cheap and easy to grow. In 2011, a group from Nanyang Technological University, in Singapore, genetically modified a strain of E. coli so it would sense and kill the human pathogen Pseudomonas aeruginosa[1], a bacterium re........ Read more »

Nazanin Saeidi, Choon Kit Wong, Tat-Ming Lo, Hung Xuan Nguyen, Hua Ling, Susanna Su Jan Leong, Chueh Loo Poh . (2011) Engineering microbes to sense and eradicate Pseudomonas aeruginosa, a human pathogen. Molecular Systems Biology. DOI: 10.1038/msb.2011.55  

Hsuan-Chen Wu, Chen-Yu Tsao, David N Quan, Yi Cheng, Matthew D Servinsky, Karen K Carter, Kathleen J Jee, Jessica L Terrell, Amin Zargar, Gary W Rubloff, Gregory F Payne, James J Valdes . (2013) Autonomous bacterial localization and gene expression based on nearby cell receptor density. Molecular Systems Biology. DOI: 10.1038/msb.2012.71  

  • September 8, 2013
  • 10:22 AM
  • 405 views

The HPV vaccine: a few things you should know

by EE Giorgi in CHIMERAS

If you are a young woman under 25 years of age, or if you have a teenager at home, chances are, your doctor told you about the HPV vaccine. HPV, or Human Papillomavirus is a DNA virus that infects keratinocytes, cells found in the epidermis and in mucous membranes. Though in some cases the virus causes painful warts, HPV infections are often asymptomatic. So why bother screening an asymptomatic virus? Because while the majority of the infected people clear the virus within 1-2 years, in less tha........ Read more »

Helen Trottier, Salaheddin Mahmud, José Carlos M Prado3, Joao S Sobrinho, Maria C Costa, Thomas E Rohan, Luisa L Villa and Eduardo L Franco. (2008) Type-Specific Duration of Human Papillomavirus Infection: Implications for Human Papillomavirus Screening and Vaccination. Infectious Diseases. DOI: 10.1086/587698  

Schiffman M, Castle PE, Jeronimo J, Rodriguez AC, & Wacholder S. (2007) Human papillomavirus and cervical cancer. Lancet, 370(9590), 890-907. PMID: 17826171  

  • August 22, 2013
  • 09:14 AM
  • 370 views

Cancer-killing viruses

by EE Giorgi in CHIMERAS

We learned last time that cancer cells are cells whose DNA has been damaged beyond repair. Somatic mutations have accumulated to the point that the cell regulatory mechanisms no longer function, causing uncontrolled growth and proliferation. Despite being anomalous, cancer cells are still part of what the immune system recognizes as "self", which makes finding a cure for cancer such a hurdle. Therapy, when available, is often invasive and debilitating because the only way to make sure that all c........ Read more »

Christian Goetz, Elena Dobrikova, Mayya Shveygert, Mikhail Dobrikov . (2011) Oncolytic poliovirus against malignant glioma. Future Virology. DOI: 10.2217/fvl.11.76  

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