The Scent of an Extinct Flower

What is the scent of an extinct flower? In the case of a Hawaiian mountain hibiscus, it’s sweet, fruity notes with a hint of ginger. How do I know? Because a biotechnology company resurrected it from the past as part of a “ghost perfume” project, and I attended event at which I was invited to sniff in the revived smell.

This company uses genetic material found in old samples of extinct flowers and puts microbes to work to reproduce the scent genes. Think of a typical factory but replace the big old metal machines with tiny living organisms. And by tiny, I mean cell-sized, not child-sized. We’re talking molecular machines.

Molecular Machines

Yeast is the factory machine of choice when it comes to these ghost scents. Humans have a long-established relationship with these single-celled microscopic fungi. Over the course of human history we’ve put it to work to create fluffy bread, tangy blue cheese, hearty beer, and life-saving antibiotics.

The yeast is genetically modified to create ghost scents. It’s not as simple as inserting a hibiscus gene into yeast. The DNA machinery is more complex and daunting. Just because genes are spliced in, doesn’t mean that they will work properly. And, as someone with a lively container of fermenting sourdough culture on my countertop, I can attest to yeast’s natural tendency to give off a sour odor. This presents yet another challenge to producing sweet scents.

But once the modified cellular machinery is working as expected, the yeast grows, ferments, and produces scent compounds that can be harvested, or purified, from it.

First Scents, Then a Stegosaurus?

In a word, no. It’s possible that extinction won’t always mean forever, but a real-life Jurassic Park scenario is a long way off. Scour your favorite online science resources to learn what they have to say about de-extinction.

That said, now is the time to introduce students to synthetic biology. Like so many emerging sciences, it’s interdisciplinary. In this case, it relies of a strong knowledge of engineering, biology and chemistry. Synthetic biologists aim to reassemble existing forms of life as well as create new ones. explains that "synthetic biology combines chemical synthesis of DNA with growing knowledge of genomics to enable researchers to quickly manufacture catalogued DNA sequences and assemble them into new genomes."

In addition to a rigorous science background, a robust understanding of philosophy, especially ethics, is also helpful for synthetic biologists.  In late 2018, a Chinese scientist, a physicist, claimed that he created genetically modified twin humans. Medical and scientific communities around the world expressed shock (and a bit skepticism), quickly condemning the action as reckless and unethical, not to mention illegal.

If you want to inject current events into your science class, synthetic biology is ripe for exploration. And, of course, no discussion of the field would be complete without Clustered Regularly Interspaced Short Palindromic Repeat, the relatively simple, revolutionary gene-editing software more commonly known as CRISPR. Other interesting and controversial topics related to synthetic biology include biohacking and gene drives.

I received my sample of ghost perfume at a storytelling event that featured author Rowan Jacobsen. He often writes about food with a nod to ecology and biology. Jacobsen recently served as the Knight Science Journalism fellow at MIT, where he focused on the environmental and evolutionary impact of synthetic biology. His article, Deleting a Species, provides an accessible place to start reading about the potential implications of this new field.