| Humans Genes Closer To Dolphins' Than Any Land Animals | 2 comments |
 19 May 2003 @ 09:31, by Raymond PowersHumans Genes Closer To Dolphins' Than Any Land Animals By: Seema Kumar Discovery Channel Online News For years, marine biologists have told us that dolphins share many traits with humans, including intelligence and friendliness. Now, a comparison of dolphin and human chromosomes shows that the genetic make-up of dolphins is amazingly similar to humans. In fact, researchers at Texas A&M University have found that dolphins have more in common with us genetically than cows, horses or pigs. "The extent of the genetic similarity came as a real surprise to us," says David Busbee of Texas A&M University, who published his results in last week's Cytogenetics and Cell Genetics. This information will not only help researchers construct the genetic blueprint of dolphins, but also bolster conservation efforts. Aided by the progress made in mapping the human genome, researchers will continue to identify individual genes on dolphin chromosomes. Busbee estimates it will save them 20 years of work, and the similarities and differences will reveal how long ago humans and dolphins branched off the evolutionary tree. Researchers at Texas A&M University applied "paints," or fluorescently labeled human chromosomes, to dolphin chromosomes, and found that 13 of 22 dolphin chromosomes were exactly the same as human chromosomes. Of the remaining nine dolphin chromosomes, many were combinations or rearrangements of their human counterparts. Researchers also identified three dolphin genes that were similar to human genes. Until now, researchers have never been able to do genetic studies of dolphins because they are a protected species, making it difficult to get tissues from them. However, Busbee was able to grow colonies of cells from fetal tissues when a female dolphin miscarried. "Dolphins are marine mammals that swim in the ocean and it was astonishing to learn that we had more in common with the dolphin than with land mammals," says Horst Hameister, professor of medical genetics at the University of Ulm in Germany. In the past 15 years, the world's dolphin populations have declined considerably, exacerbated by high levels of PCBs. Researchers speculate that PCBs impair the immune systems of dolphins, leaving them vulnerable to disease. "If we can show that humans are similar to dolphins, and anything that endangers dolphins is an equal concern for humans, it may be easier to persuade governments to become serious about combating industrial pollution and keeping oceans clean," says Busbee. |