TECH TALK TUESDAY – Our Cousins In The Sea

nancy Techie Tues 9-2-97

WOW! Did you know how much we have in common with dolphins?
Genetically speaking, we are very close cousins!
Every human chromosome has a corollary chromosome in the dolphin, say scientists. So what?

Unlocking the Genetic Code of Dolphins 
by Mark Evans

   Although one eats fish, has fins and glides effortlessly through the water while the other eats hamburgers, wears Reeboks and drives a car to work every morning, humans and dolphins may have more in common than people think, especially when it comes to genetics.

Texas A&M University veterinarians are comparing human chromosomes to those of dolphins and are finding that the two share many similarities. The scientists hope to use these similarities to identify and map the genes of dolphins.
Dr. David Busbee and his team applied human “paints,” fluorescently labeled pieces of human chromosomes, to dolphin chromosomes on microscope slides. When scientists examined photos taken with a fluorescence microscope, they found dolphin chromosomes fluorescently tagged with the labeled pieces of human chromosomes and concluded that dolphins hold many of the same chromosomes as humans.

“We started looking at these and it became very obvious to us that every human chromosome had a corollary chromosome in the dolphin,” Busbee said. “We’ve found that the dolphin genome and the human genome basically are the same. It’s just that there’s a few chromosomal rearrangements that have changed the way the genetic material is put together.”

The scientists are trying to determine if the same similarities are true for individual genes on the chromosomes. For every dolphin chromosome, they are selecting a gene found on the human chromosome and seeing if that same gene shows up in the dolphin at the same place on the chromosome.

“We expect there are a number of places where the dolphin genome will reflect differences with the human genome,” he said.

These differences will tell scientists how long ago dolphins and humans embarked down different branches on the evolutionary tree. According to their genes, Busbee said, dolphins are most closely related to cows, antelopes and giraffes, and the domestic pig may be their closest relative.

If scientists can determine the genetic information shared by humans and dolphins, he said, then they may be able to save themselves a lot of time and effort in constructing a genetic map of dolphins. Busbee said they may be able to save as much as 20 years by tapping into all of the work that has been done mapping human genes and using this information to identify matching genes in dolphins.

“Nobody has ever done genetics work on Cetaceans — whales, dolphins and porpoises,” he said “No molecular genetics work has been done with this group before.”