Left-Handed DNA: Is That Right?

There’s a certain group of people (including this blog post author) who derive no small amount of amusement from seeing stock photos of DNA and pointing out flaws in the structure. It’s even more amusing when these photos are used in marketing by life science companies. The most common flaw: the DNA molecule is a left-handed double helix.

What does that even mean? DNA, like many organic chemicals in biology, is a chiral molecule. That is, it can exist in two structural forms that are mirror images of each other but are not superimposable (enantiomers). Just like your left and right hands are mirror images of each other, the two DNA structures are left-handed and right-handed double helices. The DNA double helix is chiral, because its building blocks (nucleotides) are chiral.

Two DNA helices that are mirror images

It can be challenging, at first glance, to tell whether an image of DNA is left-handed or right-handed. Various helpful hints are available; however, the one that I’ve found easiest to remember is described in a blog post by Professor Emeritus Larry Moran at the University of Toronto:

Imagine that the double helix is a spiral staircase, and you’re walking down the staircase. If you’re turning to the right as you descend, the DNA structure is right-handed; if turning to the left, it’s left-handed. In the image shown earlier, the DNA molecule on the right is a right-handed double helix, while its mirror image is left-handed.

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Small Molecule Therapies and Immunotherapies: An Introduction to Targeted Cancer Treatments

Cancer is a deceptively singular term for hundreds of different diseases. These diseases can affect almost any part of the body.  In the United States, cancer is the second most common cause of death (1). At its most basic level, however, cancer is the abnormal and uncontrolled division of cells resulting from genetic changes in one or more cells.

This prolific cell division is what many standard chemotherapies act upon. These therapies are developed to kill rapidly dividing cells but often don’t discriminate between normal and cancerous cells. In contrast, targeted therapies are designed to interact with (or target) specific pathways, processes or proteins whose abnormal behavior is associated with cancer development and growth. Targeting these abnormal cellular functions can counteract cancer in different ways. They can interfere with tumor growth, carry other drugs into tumor cells or help the immune system find and kill cancerous cells. Targeted therapies can be loosely divided into two categories: small molecule therapies and immunotherapies.

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Exploring Investigative Genetic Genealogy 

In the past few years, and as seen as a popular topic at ISHI 33, investigative genetic genealogy (IGG) has rapidly grown and emerged as a new field of science to identify human remains or cold case crime scene samples. The technique traces potential genetic familial relationships through DNA databases. Although genetic genealogy and public DNA databases have been around for quite some time, what’s new is their use by law enforcement.

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It’s Time to Automate Your Plasmid Purification

In the fifty years since the first reported transformation of recombinant plasmids into bacteria (1), plasmid cloning has become one of the pillars of synthetic biology research and manufacturing biopharmaceuticals.

But purifying plasmids is no small feat. It can often take hours of hands-on time to go from culture to eluate with low-throughput and time-sensitive manual methods. Automating plasmid purification is the way to go, whether you’re isolating a single plasmid from a large volume culture or creating a library of thousands of different constructs.

Working in a biosafety cabinet filled with flasks and culture plates containing yellow bacterial cultures, a researcher harvests a culture.
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How We Connected in 2022

The Finance and Accounting team attends a Milwaukee Brewers game for team bonding

As the calendars turn to a new year, we love to take a moment to look back at the previous year. A lot happened at Promega in 2022! We launched Spectrum CE System, the first capillary electrophoresis instrument compatible with 8-color STR analysis chemistry. We announced that over 20% of our global electricity usage is now generated by renewable sources. We unveiled new employee benefits that aim to support employees dealing with specific life challenges.

Perhaps most importantly, in 2022 we prioritized meaningful connections and deepening our relationships with one another. From honoring employee contributions to marking significant milestones, here are just a few ways Promega teams around the world celebrated and connected in the past year.

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Avoid the Cloning Blues This Season

I was blasting a holiday music playlist while driving recently, and Presley’s Blue Christmas played. I couldn’t get the phrase “Christmas Cloning Blues” out of my mind, and by the time I arrived at my destination, this happened:

Cloning Blues Christmas

(to the tune of Blue Christmas by Elvis Presley)

Blue and white colonies on a selective plate. Careful planning can help you avoid the cloning blues
Blue/White cloning is a standard technique in molecular biology labs.

I’ll have a blue Christmas without you

Colonies so blue, insert without you

Incubating my plates at 37 degrees

Won’t be the same if you’re not in lacZ


And all those blue colonies are forming

When my lab mates’ clonings are performing

They’ll be doing alright,

With their plates all filled with white

But I’ll have a blue, blue, blue cloning

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Rocking Out with the Promega Band: Major Groove!

Promega employees playing with the band Major Groove
A group of Promega employees rehearses their set for the Employee Recognition Meeting reception

Have you ever heard Guns ‘n’ Roses and Lizzo in the same concert?

When the Promega employee band Major Groove takes the stage, you never know what they might play!

The Promega band started with a handful of employees in 2006 and has grown to include more than 50 active musicians. Today, they play at company meetings, picnics, art shows and much more.

“During my interview process, I was sent a list of links to learn more about Promega. I was like, “Hold the phone! This company has a band!” says Kathryn Sauter, a Business Analyst on the Global Logistics team. “I never thought I’d have an opportunity to participate in a musical extracurricular activity at a place where I work. Promega immediately shot to the top of my list.”

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Our Top Three Most-Viewed Blog Posts of 2022

In 2022, our bloggers wrote on topics ranging from monkeypox outbreaks to cultured meat in biotech labs to preventing the next pandemic. Our top three most-viewed blog posts this year have the commonality of Promega products helping to advance important research in different fields and push science a step forward in the world. Take a look at Promega’s top three most-viewed blog posts of 2022.

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Growing Our Understanding of Rose Rosette Virus Through Reverse Genetics

Viral particle representing lethal Rose Rosette Emaravirus with red rose.

Roses, the universal symbol of love and affection, are one of the most popular ornamental flowering shrubs used by landscapers and home gardeners and account for almost half of the billion-dollar ornamental plant market. The growing prevalence of rose rosette disease poses a significant threat to these industries.  This lethal disease is caused by the Rose rosette emaravirus (RRV) and transmitted by the tiny eriophyid mite, Phyllocoptes fructiphilus. Infection by RRV results in prolific growth of clustered and bunched plant shoots (witches’ broom), malformed flowers and leaves, malformed shoots and enlarged stems and abundant leaf growth and thorniness. This excessive growth depletes the plant’s energy, eventually causing death.

Emerging and Devastating Plant Viruses of the Genus Emaravirus

RRV is a single-stranded, segmented, negative-sense RNA virus belonging to the genus Emaravirus, a relatively new genus that was established in 2012. These emerging viruses can be devastating to trees, herbaceous woody plants and vines. At Texas A&M University, Dr. Jeanmarie Verchot’s lab is working to better characterize and understand these new viruses. In addition to threatening roses, these viruses cause damage to important agriculture crops such as wheat and pigeon peas. They also endanger sensitive ecosystems when they infect plants specialized to a particular habitat, as is the case with Palo verde broom virus infection of palo verde trees of the Sonoran Desert (1).

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From Student Debt Assistance to Family-Forming Support: Benefits and Well-Being Go Hand in Hand 

You know this, but it bears repeating. Prioritizing physical, psychological, emotional and financial wellness is key to supporting our overall well-being. This holds true during the busy holiday season and throughout the entire year.  

Employee benefits that address emotional, physical and financial well-being

It can also be easier said than done, so we need as much support as possible in this vital endeavor. An in-depth framework recently published by the US Surgeon General outlines a vision of the workplace as an engine of well-being. The report states, “Our workplaces play a significant role in our lives. Work affects both our physical and mental well-being – in good ways and bad. The COVID-19 pandemic brought the relationship between work and well-being into clearer focus.”   

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