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Andrew Porterfield

A freelance life science writer for more than 20 years, I’ve worked for academic institutions, startup biotechs, major biopharmaceutical corporations and consultancies. I’ve also worked as a journalist for various organizations, and am currently the agriculture editor for the Genetic Literacy Project. I have a MS in biotechnology from the University of Maryland, and a BA in physical anthropology from the University of Pennsylvania. I live on California’s central coast.

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Articles by Andrew Porterfield

A woman holding a magnifying glass representing detecting post-translational modifications

Detecting Post-Translational Modifications

By Andrew Porterfield | October 20, 2020

A quick start guide to methods of assessing protein post-translational modifications

The Ins & Outs of Illumina Sequencing

The Ins & Outs of Illumina Sequencing

By Andrew Porterfield | August 30, 2016

The future of personalized medicine depends on affordable DNA sequencing. In the race for the $1,000 genome, several sequencer manufacturers are working on making equipment that can sequence DNA and RNA faster and more accurately. But so far, only one company – San Diego, California-based Illumina – has US FDA regulatory approval to use its…

How Thermophilic Bacteria Survive, Part II: DNA

How Thermophilic Bacteria Survive, Part II: DNA

By Andrew Porterfield | July 9, 2016

In part I, I answered the question, “How do proteins in thermophiles survive under high temperatures?” In this part, I’ll look look at how nucleic acids survive -thrive, even- in conditions that are too hot for most of us, but ideal for a number of organisms, including the one that gave us Taq polymerase and…

Ion Torrent

All in the Chip: Ion Torrent Sequencers

By Andrew Porterfield | July 9, 2016

Ion Torrent technology, when it was introduced in 2010, was one of several machines that promised to revolutionize genetics. These were benchtop machines that showed their prowess in quickly sequencing smaller exomes and other DNA samples (about 10-20 million bases per run, compared to Illumina HiSeq, which could read 250 billion bases in a run).…

Southern (blot) exposure remains a useful technique

Southern (blot) exposure remains a useful technique

By Andrew Porterfield | July 9, 2016

At a meeting recently, I asked two PhD molecular biologists about the last time they used a Southern blot. After nearly a minute of unrestrained laughter, they asked “Who on earth still does that?” “Maybe for a very, very specific use,” conjectured one of the scientists. When I asked the scientist who taught me the…

Catalyzing Through Confusion: Making (Some) Sense of Enzyme Units

Catalyzing Through Confusion: Making (Some) Sense of Enzyme Units

By Andrew Porterfield | July 9, 2016

On the surface, it would seem easy enough to pick an enzyme (or an amount of enzyme) for an experiment. Just look at the concentration on the label, adjust accordingly, and you’re on your way. Alas, not with enzymes. The number of units used to measure enzymes is dizzying. However, it’s better now than it…

A Guide to Genetic Variants

A Guide to Genetic Variants

By Andrew Porterfield | May 15, 2015

Perhaps one of the most significant discoveries in modern genetics (after the genetic code was laid out, anyway) is the role of genetic variations in evolution, disease and the creation of plants and animals. While the Human Genome Project (and a lot of other genome projects, for that matter) showed how many genes living things…

A Quick Guide to pH, pKa and pI

A Quick Guide to pH, pKa and pI

By Andrew Porterfield | January 7, 2015

They’re easy numbers to take for granted, so it’s a good exercise once in a while to remind ourselves what pH, pKa and pI stand for: pH—the measure of acidity. It’s the negative logarithm of the proton concentration. pKa—an association constant. It’s the negative logarithm of the ratio of dissociated acid and conjugated base, over…

How Does BLAST Work?

How Does BLAST Work?

By Andrew Porterfield | July 23, 2014

More than a pun on the explosive growth of sequencing data, BLAST makes annotation and comparisons of similar sequences much easier. Created by a group at the U.S. National Center for Biotechnology Information in 1991, the Basic Local Alignment Search Tool is arguably the most heavily used tool for sequence analysis (that’s available for free,…

Ready to commercialise your research? Bioincubators are worth considering

Ready to commercialise your research? Bioincubators are worth considering

By Andrew Porterfield | April 30, 2014

Finding adequate sources of funding is the primary challenge of just about any startup company, and biotechnology is no different. In fact, the regulatory, scientific and logistical requirements of making a new drug or device could easily be the most challenging of any industry. In addition, the global recession of 2007-2009 (combined with austerity measures…

Don’t Get Lost in RNA-seq Translation: RNA Sequencing the NGS Way

Don’t Get Lost in RNA-seq Translation: RNA Sequencing the NGS Way

By Andrew Porterfield | March 27, 2014

DNA sequencing (PCR, Sanger or next-generation sequencing (NGS)) is a now familiar part of any molecular biology lab. But ‘RNA-seq’, the so-called “Cinderella of genetics”, is now becoming the belle of the ball, providing new insights into this most central molecule of the ‘central dogma’.  The many flavors of RNA Whilst genomic DNA is the…

Benchside Matchmaking—Finding the Right Buffer for Your Experiment

Benchside Matchmaking—Finding the Right Buffer for Your Experiment

By Andrew Porterfield | March 24, 2014

Buffers are often taken for granted, but they can make or break an experiment.  In previous posts, we’ve talked about the wide ranges of buffers available for biological research and the characteristics of a “Good” buffer. Organic buffers are not inert! They can interact with your experimental molecule, or change pH due to changes in…

What Makes a “Good” Laboratory Buffer?

By Andrew Porterfield | January 22, 2014

Just about any molecular biology experiment will involve the action of enzymes or other active proteins. And when enzymes are involved, the pH of your experimental environment is going to change. This is because most enzymatic reactions involve the loss or gain of hydrogen ions (protons), which modifies the pH of the environment. Biological systems…

The Irish Potato Famine: NGS Unearths The Fungus Responsible For Over 1 Million Deaths

By Andrew Porterfield | November 7, 2013

The Irish Famine (or ‘Great Potato Famine’ if you live outside the Emerald Isle) killed one million people and forced another million to leave the country between 1845 and 1852. It was caused by a blight on the country’s main food stock- the Irish ‘Lumper’ potato. Now, researchers have identified the genome of the blight…

Keeping up With the Periodic Table

Keeping up With the Periodic Table

By Andrew Porterfield | October 16, 2013

The periodic table, that ingeniously arranged display of atomic weights, numbers and elements that’s probably posted on a door way in the back of your lab, isn’t a static document. It’s changed a fair amount in its lifetime, largely as weights are refined and new elements added. However in 2011, the International Union of Pure…

What’s in a Number: Getting the Right Passage in Cell Culture

By Andrew Porterfield | May 1, 2013

Getting the Right Passage Number Using an American Type Culture Collection (ATCC) reference strain for every experiment would be great, but not all that practical. So, most labs subculture their cells into a new vessel. This subculture is also known as a “passage.” A passage number is the number of times a cell culture has…

Neigh need for NGS for meat testing- in the mane, PCR is enough!

By Andrew Porterfield | March 28, 2013

Horsemeat testing is continuing to show that contamination, while lower than when first reported, is still not, well, stable! There’s been horse meat around for donkey’s years..! The UK Food Standards Agency (FSA) showed at the end of March that it’s testing found 352 samples out of 362 contained less than 1% horsemeat. Of the…

Sifting Detritus—Extracting DNA and RNA Samples from Soil and Feces

By Andrew Porterfield | March 26, 2013

The value of PCR to forensics has been known for a long time; but now, getting purified DNA and RNA samples from soil and fecal samples is becoming more important and commonplace as tests for environmental impacts, disease spread, and even biomarkers for colon cancer become more prevalent. And if you thought getting nucleic acids…

Big Foot In Mouth Or Tongue In Cheek?! Sasquatch Sequenced.

By Andrew Porterfield | February 28, 2013

“Bigfoot is real, according to genetic analysis.” That bold statement appears on the website of a new journal, the sole paper in which presents what it claims is a mitochondrial DNA match and gene sequence of the (still-mythical) creature Sasquatch, or Bigfoot. Taking samples from Sasquatch Melba Ketchum, a veterinarian who runs a DNA testing…

I Know Who You Are: Using ‘Private’ DNA Sequences To Identify People

By Andrew Porterfield | February 14, 2013

Searching for ancestors online is a popular activity. So is having your DNA sequenced. But merging the two has created a problem; it’s very, very easy to use genealogy software and DNA sequence data to identify people who are supposed to be anonymous. A spanner in the works This means all sorts of data, like…

Do Bad Genes Beget Disease? Hey, Not So Fast!

By Andrew Porterfield | February 7, 2013

The purpose of genetic testing is to find altered genes that could cause disease. Consequently, people could be treated, or prospective parents can make decisions about having children. However, scientists are finding that having a gene which causes disease doesn’t necessarily cause that disease! We are all mutants Researchers at Cambridge and Cardiff universities found that a…

Do Your Homework to Find Good Reference Genes

Do Your Homework to Find Good Reference Genes

By Andrew Porterfield | January 28, 2013

Comparing and measuring gene expression is certainly an integral part of research—gene expression patterns continue to show us how different cell networks are regulated, and point to new biological pathways and possible treatments for disease. But one crucial part of gene expression lies in making sure that differences in gene expression are due to gene…

We Learn a Wee Bit More about Proteins—from Wii

We Learn a Wee Bit More about Proteins—from Wii

By Andrew Porterfield | December 19, 2012

About thirteen years ago, a group of science journalists gathered in a darkened lab at Rice University in Houston, Texas. The lights went off, and the participants took turns donning a clunky helmet with darkened visor. By moving the right thumb, each helmet-wearing reporter suddenly was whisked down the middle of protein ribbon, twisted through…

NHS uses NGS to combat MRSA!

By Andrew Porterfield | November 22, 2012

Methicillin-resistant Staphylococcus aureus (MRSA) persistently plagues hospitals worldwide. Until now, hospital (or healthcare) MRSA (HA-MRSA) was of a different lineage from MRSA found in the community. Since HA-MRSA could not survive in a non-hospital setting, this made things rather convenient. Testing for HA-MRSA was routine and the isolates, in particular one called ST22, could easily…

Who Found the First Plasmid?

By Andrew Porterfield | November 9, 2012

Plasmids—the loops of DNA in bacteria that form the original foundation of biotechnology—were being discovered constantly in the 1940s and 1950s. The only problem was, they were called everything but. Series of scientists found bacteriophages and other strange loops of somatic DNA, and gave them a series of names, including: pangenes, bioblasts, plasmagenes, plastogenes, choncriogenes,…

Genomes on cell phones- there’s no app for that…yet!

By Andrew Porterfield | November 8, 2012

A long, long time ago- before the human genome sequence was announced, a cancer specialist friend wrote a whimsical essay in a university newsletter. He predicted that future patients would drive to a clinical data center, plug a flash drive into a computer and have their genomes scanned for current and potential disease. The reaction…

You’re Closer to the Clinic Than You Think: NGS and Clinical Trials

By Andrew Porterfield | October 18, 2012

A decade or so ago, the phrase ‘translational research’ began making its rounds through laboratories- it was supposed to take molecular biology results and apply them directly to patients. It brought about things like gene therapy, stem cell therapy, and so forth. You get the idea- valuable research, but not immediately injectable. Valuable and cheap…

How the Ion Torrent Sequencer works

By Andrew Porterfield | September 6, 2012

Just before Life Technologies purchased the start-up company Ion Torrent, the fledgling company was dealing with a torrent of another kind—worldwide media interest in its new sequencing technology, which promised to bring the price of next-generation, massively parallel sequencing down to $1,000 per run. Since that dramatic announcement in the summer of 2011, Life Technologies…

How to Save Our Science—a Case Study

How to Save Our Science—a Case Study

By Andrew Porterfield | August 27, 2012

Mentioning the abbreviation “GMO” yields one of two reactions: fascination with the biotechnology of creating food and other organisms that thrive despite pests or bad weather, or horror at the idea of creating an unknown, dangerous monster in the laboratory. Rothamsted Research, in Harpenden, England, was yet another biotechnology lab faced with the latter reaction…

This Is Your Brain On NGS

By Andrew Porterfield | August 23, 2012

Neuroscience presents unique genetics challenges. Genetics of the brain means studying an enormous number of mutations. In addition, many loci encode proteins that interact with each other, so a mutation that affects one protein could, in fact, affect the function of other proteins in a given pathway, even if the other proteins are not mutated.…

How Pure is Your Cell Culture Broth? Comparing Mycoplasma Detection Kits

How Pure is Your Cell Culture Broth? Comparing Mycoplasma Detection Kits

By Andrew Porterfield | August 1, 2012

Mycoplasmas are the most difficult-to-detect organisms in your eukaryotic cell culture. And they can be the most dangerous; they can disrupt cell growth and differentiation and even apoptotic patterns without you even knowing what’s going on until it’s too late. Traditional cell culture methods can take up to a month to yield results, which means…

What’s THAT Doing in My Culture?

What’s THAT Doing in My Culture?

By Andrew Porterfield | May 28, 2012

A young laboratory technician was puzzled by his plates when he pulled them out of the warm room. They never looked that cloudy and fuzzy before. He brought them to his lab director, who shook her head sadly; together, they threw the plates away. Does this story sound familiar? What probably happened was an all-too…

The Invisible Horde: Attacking Mycoplasma Infections

By Andrew Porterfield | May 21, 2012

Mycoplasma infections are very, very bad news; these special prokaryotes can rapidly spread through your cell culture and inhibit cell proliferation, induce apoptosis, cytokines and radicals, and otherwise transform your cells. Worst of all, since contamination is not easy to spot, you may not realize your culture is contaminated until it’s too late. The 100…

How Do Buffers Work?

How Do Buffers Work?

By Andrew Porterfield | April 16, 2012

A former colleague and friend of mine worked in technical support, taking calls from scientists. Most of the calls came from life science researchers frustrated by failed experiments. My friend would listen for a bit, then almost always exclaim in very charming but booming Russian-accented English, “No! You must add buffer to the experiment! It…

The Secrets of Thermophile Survival: Part I

The Secrets of Thermophile Survival: Part I

By Andrew Porterfield | July 13, 2009

In response to my last article, The Taq behind PCR, one of our readers, Bonnie Barrilleaux, asked whether DNA could naturally survive at temperatures that would denature it. It also begged the question; how do proteins stay intact and functioning at these high (55°C and up) temperatures? It turns out, cells do a lot of…

The Taq behind PCR

The Taq behind PCR

By Andrew Porterfield | June 10, 2009

Nobel Laureate Kary Mullis is generally credited with inventing the polymerase chain reaction, but his discovery owes a lot to a microbiologist who loved to travel, some refuted assumptions of what can live in hot springs, and a now-closed field station in Yellowstone National Park. Here’s the story. In the 1960s, Thomas Brock was a…

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