Hexbyte Glen Cove For 50 years, biologist has studied bottlenose dolphins from a research center on Florida's Gulf Coast thumbnail

Hexbyte Glen Cove For 50 years, biologist has studied bottlenose dolphins from a research center on Florida’s Gulf Coast

Hexbyte Glen Cove

Credit: CC0 Public Domain

Beginning his work in marine biology, Randy Wells thought he was a shark guy.

But the teenager whose family had just moved from Peoria to Florida’s Gulf Coast volunteered to help a local researcher study the migration patterns of the bottlenose dolphins off of Sarasota.

And now it’s 50 years later and Wells—a staff scientist at Brookfield Zoo in suburban Chicago since 1989—heads the world’s longest running study of a marine mammal population in the wild, tracking the lives, loves and losses of some 170 Sarasota Bay dolphins and delivering globally significant insight into these creatures that have long fascinated humans.

In the process Wells has become one of the best-known dolphin guys on the planet—and helped make Brookfield more than just a landlocked zoo in a sleepy western suburb.

But the essence of what he has learned, Wells says, is not that different from life in a Chicago ‘burb. He explained:

“So when we started, we had no idea what we were going to find back in 1970. It was completely exploratory, with a pilot tagging study back then, and it could have gone a variety of directions. But the idea that we could find the same identifiable individual dolphins time and time again within a fairly limited area set the stage for everything we’ve been able to do since then.

“So we can recognize 95 percent of the dolphins in Sarasota waters just from looking at their dorsal fin, looking for patterns of nicks and notches on their fins. Within that 170-dolphin community, we have been monitoring them through six generations. At any given time, we can have up to five concurrent generations within a lineage.

“So it’s very much like a suburban neighborhood outside of Chicago. For example, I lived in LaGrange Park for a few years and in the neighborhood that I lived in, there were multiple generations of the same family on back-to-back streets. And that’s kind of how I envision what’s going on in Sarasota.”

That explanation is true enough, but it doesn’t capture the breadth of work that Wells and scores of colleagues and visiting scientists have been able to do over the years from their headquarters on Sarasota Bay.

After first establishing the crucial fact that the wild dolphin population was resident, rather than transitory, Wells and what is now called the Sarasota Dolphin Research Program have helped prove the damage to dolphins and the Gulf of Mexico ecosystem caused by the Deepwater Horizon oil spill, spotlighted the impact of red tide events, pioneered techniques in health assessment of dolphins and established that dolphins can live to age 67 and give birth up to age 48.

“Scotchgard, which we used to put on couches?” said Stuart Strahl, president and CEO of Chicago Zoological Society, the parent organization of Brookfield Zoo. “One of the reasons that’s off the shelves now, it’s a bioaccumulator like DDT.” The original formulation of the 3M product, “that’s off the shelves because of Randy’s research, because of what he found in the dolphins.”

The list of SDRP impacts Brookfield has compiled to mark the 50th anniversary, which happened officially in October, is remarkable for their length and detail, but it would be wrong to think of the program as all white lab coats and clipboards.

“Randy and his crew, they’re the most prolific scientists I’ve ever met,” said Strahl, who has a research background himself. “They are some of the most remarkable humans I’ve seen in the field, and the enthusiasm they have when they see a dolphin they haven’t seen in a while is terrific. ‘That must be so and so!’ It’s infectious when you’re around them.”

And the reason for Brookfeild to continue supporting the program—to the tune of almost $1 million annually, primarily through grants and philanthropy, the zoo says—is because it complements the work done on the zoo campus.

“We have an obligation to engage people in not just the animals that we have on display but also to learn their stories and learn the stories of what things they face in the wild and how those issues can be mitigated,” said Strahl. “It’s two halves of a solution for wildlife.”

Brookfield support is crucial to the project, pointed out Peter Tyack, a professor at University of St Andrews in Scotland who studies cetacean vocalizing and has done research on the Sarasota dolphins.

“Having reliable continuous support is what’s essential for this kind of long-term study,” Tyack said.

And having so much data over so long a time is essential to understanding the big problems of today, including the effects of climate change, Tyack said. “What I say about Randy’s project is … the older the data, the more valuable it gets to us today in terms of tracking long-term trends.”

Another profound impact of the program has been in the development of scientists.

Trevor Spradlin, who is now deputy chief of the marine mammal and sea turtle conservation division at the National Oceanic and Atmospheric Administration, the leading federal marine conservation agency, first experienced scientific field work as a volunteer with Wells in 1989, he recalled.

“Randy has been such a nurturer to so many different generations of marine mammal biologists,” Spradlin said, noting that SDRP’s work is “the blueprint for what we know about coastal dolphins around the world.”

“He’s done so much not just for dolphins but also for the whole field of marine mammal science,” Spradlin said. “He’s provided platforms of opportunity for so many scientists around the world to learn about dolphins and wildlife conservation techniques and procedures.”

More than 80 doctoral dissertations and masters theses have involved work done at SDRP, the zoo says, and just since 1991 more than 400 interns have trained there.

And the work has been a backbone of NOAA’s efforts “to get people to respectfully view animals in the wild,” Spradlin said. “All these efforts to promote safe and reasonable dolphin viewing really have their genesis with Randy. It’s more than just cool science—and it is cool science—but it’s also very important data to help preserve and protect these animals.”

Even growing up in Peoria, Wells was fascinated by water, he said, the result of family spring breaks: “I just—I was taken by the ocean. For years my parents led a delegation that eventually grew to over 500 Peorians that would come down and take over multiple hotels on Panama City Beach.”

The family moved when he was in high school to Siesta Key, just off Sarasota, and “I was so ready for the move,” Wells said. He was able to take classes in high school, and when his dad’s company sold a house to researcher moving from California to study sharks and dolphins, Wells’s father asked the man if he needed an assistant.

Wells began working with that researcher, Blair Irvine (who now sits on the SDRP board), and it was an unfunded offshoot program tagging coastal , Wells said, that led to the pioneering work that established the animals were residents of the area rather than mere passers by.

He has seen remarkable changes in the field. A 1977 marine mammal conference drew fewer than 200 scientists, he said, while one held recently in Barcelona attracted more than 2500. Technology has dramatically aided in the work researchers are able to do, from unobtrusive tracking devices to the dolphin identifying and age-estimating work pioneered by Wells’s team.

But it all comes back to that baseline work his project has done.

“We know the individuals,” he said. “We know how old they are. We know where they are, who they’re related to on the maternal side. And in many cases, with analyses that have just been completed, we know who their fathers are. We have a good sense of their condition in terms of their health and their contaminant load. We know where they spend their time. We know with whom they spend their time. And so with that background knowledge, it just makes all kinds of research possible.

“And it’s just gotten more interesting as time as gone on and we’ve gotten to know these individuals.”

Wells turned 67 in Novembe

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Hexbyte Glen Cove Cell biologists decipher signal that ensures no chromosome is left behind thumbnail

Hexbyte Glen Cove Cell biologists decipher signal that ensures no chromosome is left behind

Hexbyte Glen Cove

A human cell is featured during mitosis with its chromosomes (gray areas) aligned. The region known as the kinetochore (colored with yellow, red and cyan markers) is the origin of the checkpoint signal that acts as a safety check against premature cell division and is the focus of UC San Diego researchers’ study. Credit: Desai Lab, UC San Diego

Starting as a single cell, organisms undergo millions of generations of divisions to ultimately generate the bones, heart, brain and other components that make up a living being. The mainspring within this intricate process is the transfer of DNA through each subsequent cell split within discrete packets called chromosomes.

It’s critical that all chromosomes are duplicated and precisely distributed through every generation of . If the inherited chromosome components are altered, even slightly, birth defects and certain cancers can result.

A new study published in the journal Science by postdoctoral scholar Pablo Lara-Gonzalez, Division of Biological Sciences Professor Arshad Desai and their colleagues addresses the mystery of how chromosomes are inherited correctly every time a cell divides. Using a novel probe that monitors a key aspect of this process, Lara-Gonzalez and Desai have detailed the mechanics behind a “wait” signal that ensures that cell division isn’t prematurely set in motion.

The researchers concentrated their investigations on a pathway in the cell called the “spindle checkpoint,” which is a type of quality control mechanism that ensures accurate chromosome inheritance during cell division. The spindle checkpoint pathway is activated at a site on the chromosome called the kinetochore, a mechanical interface where protein fibers are coupled to pull chromosomes apart.

An embryo of a roundworm (C. elegans) is shown undergoing its first division. The embryo expresses fluorescent probes that mark the chromosomes in magenta and the microtubules—the filaments that separate the chromosomes—in gray. Credit: Desai Lab, UC San Diego

“When kinetochores are not attached to these protein fibers, they send out a ‘wait’ signal that halts the cell in mitosis (cell division), thereby giving time for attachments to be formed,” said Desai, a professor in the Section of Cell and Developmental Biology (Biological Sciences) and the Department of Cellular and Molecular Medicine (School of Medicine). “In this way, the cell makes sure all chromosomes are attached properly and ready to be pulled apart before the cell divides, thereby leaving no chromosome behind.”

In the Science paper, the researchers describe how the wait checkpoint signal is specifically generated at kinetochores of unattached . Serendipitously, they developed a fluorescent probe that enabled them to watch for the first time the key molecular event in wait signal generation at kinetochores in living .

“This work identified a key ‘matchmaker’ molecule that brings together two constituents of the wait signal that do not like to associate with each other on their own,” said Lara-Gonzalez. “These findings help explain why the ‘wait’ checkpoint signal is selectively generated at kinetochores and not elsewhere in the cell.”

The findings offer a framework for ways in which the accuracy of chromosome inheritance can be lowered in certain states of disease, such as cancer, the researchers said.



More information:
Pablo Lara-Gonzalez et al, A tripartite mechanism catalyzes Mad2-Cdc20 assembly at unattached kinetochores, Science (2020). DOI: 10.1126/science.abc1424

Citation:
Cell biologists decipher signal that ensures no chromosome is left behind (2021, January 6)
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