The box finally arrived. I sliced it open and pulled out a tiny container buried beneath the swirling fog of dry ice. Inside were four precious vials of frozen cells containing the last remaining hope for a species teetering on the brink of extinction.

A year prior in the spring of 2017, I began working for the Vertebrate Genomes Project (VGP), a lab at Rockefeller University with a moonshot goal of mapping out the entire genetic code of every living species on earth. More specifically, they were building “reference genomes,” which is akin to recreating the picture on the top of the puzzle box. It’s a complete map of where a specific piece of DNA can be found. They are essential for answering fundamental questions of biology and evolution, but up until then they only existed for a few well-studied species. The VGP embarked on an uncharted territory of science, promising reference genomes with few errors for rare and unaccounted for species. I was lured to New York City by the prospect of being part of a project that could make a real and meaningful difference in the world.

Finding biological tissues for the first targeted species was like a real-life game of Pokemon. Museum archives, National Geographic articles, nature documentaries, and Twitter discussions, all teemed with the potential of securing a sample. However, scientists were reluctant to hand-over their last tube of precious tissues without a guarantee of new discoveries. What we needed was a compelling story, one that proved our work had the power to advance science in novel ways. During my hunt for charismatic creatures, an enthusiastic graduate student came to plead his case for the world’s smallest and most endangered porpoise, the vaquita. “You must get a genetic record of this species before it’s gone,” he said. Game on.

I poured over the swash-buckling tale of this docile creature that was disappearing in plain sight. The vaquita, the smallest marine mammal, are found only in the upper regions of the Gulf of California. With dark markings around its eyes and mouth, this miniature porpoise is affectionately known as the “goth kid of the cetacean clan.” According to the Mexican government’s National Ecology and Climate Change Institute, 90% of the vaquita’s population dramatically declined between 2011 and 2017. Its elusive demeanor makes it difficult for scientists to spot them, but it’s estimated that less than 20 remain. The vaquita’s population has been decimated by gillnets used to catch the totoaba, a gargantuan fish killed exclusively for its swim bladder. Believed to have powerful medicinal properties, a dried totoaba swim bladder cost $46,000 per kilogram on the Chinese black market. In an effort to prevent the vaquita from becoming by-catch, the Mexican government banned gillnet fishing in 2015 and compensated fishing communities in the region. Unfortunately, the lucrative business of catching totoaba was still too good to resist and increased law enforcement pushed the system underground. Soon, armed fishing boats operated only at night and Chinese syndicates took root within Mexico, spiraling the situation at sea into an insurmountable problem.

Both spellbound and dismayed by this tragic story, I began my mission to find any connection to the vaquita. Several weeks of cold emails were met with radio silence, until one serendipitous introduction to Phillip Morin, a marine mammal geneticist at National Oceanic and Atmospheric Administration (NOAA) Southwest Fisheries Science Center in San Diego. Morin and his colleagues had dedicated their life's work to the vaquita and other endangered marine mammals. At the time, he had tons of genetic information from many different individuals over the years, but the only reference genomes available were from distantly related species. Imagine putting together a puzzle with a different picture as a guide and half the pieces were missing from the box. If our lab could provide the vaquita’s complete genetic record, Morin could compare it with his data to unlock deeper information on how the vaquita’s genes changed over time and its chances of survival in the future.

Our best bet for finding this tissue were the organizers of Vaquita CPR, a last-ditch captive breeding effort to locate, capture and transfer the vaquita to a protected pen (El Nido) in the northern part of the Gulf. I had passed along our sample collection protocols to the team, in hopes that someone would collect blood samples during the routine veterinary check-ups. Unfortunately, the tragic news arrived in October 2017 that the Vaquita CPR mission had been called off after one of the captured females had passed away due to cardiac stress. But, her legacy lives on. In the wee hours of the morning, Morin raced a cooler of tissues across the Mexico-California border and transferred the samples to the San Diego Zoo’s Beckman Center for Conservation Research. There, the cell lines were made from the tissues and frozen until they were ready to be shipped off to our lab.

Reality began to sink in upon delivery of the vaquita’s frozen cells. The next phase of this endeavor rested on my shoulders. Breaking open the walls of each tiny cell and extracting out the DNA would be my small contribution in the remarkable fight. Within a year, our lab successfully produced the most precise genetic record of any dolphin, porpoise, or whale. Wit the new genome and Morin’s existing data, the full picture of the vaquita revealed itself: they had been thriving in low numbers for over 200,000 years. Typically, inbreeding generates harmful mutations and lowers genetic diversity. For this reason, scientists had expected the vaquita would never recover even if gillnets were no longer a threat. However, the vaquita’s ability to survive in a small population for a long period meant they had time to purge out these harmful genes and adapt to their environment. Now there’s clear evidence to show that humans are not even giving them a fighting chance. Our team was finally able to show the scientific community that the resources, time, and money required for our work were a worthy investment.

As their fate stands in limbo, this analysis of the vaquita’s genes has brought a ray of hope for other endangered species. Researchers are beginning to uncover more evidence that other toothed whales and dolphins have also persisted at low numbers over hundreds of thousands of years and have not been plagued by the detrimental effects of inbreeding. As scientific discovery continues to race the clock for our rapidly declining biodiversity, perhaps these cells still hold more secrets to saving the lives of other species in danger.