- 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.
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- In fact, researchers at Texas A&M
University have found that dolphins have more in common with us genetically
than cows, horses or pigs.
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- "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.
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- This information will not only help researchers
construct the genetic blueprint of dolphins, but also bolster conservation
efforts.
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- 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.
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- 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.
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- 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.
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- 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.
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- "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.
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- 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.
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- "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.
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- By Seema Kumar, Discovery Channel Online
News
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- DISCOVERY ONLINE
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- Picture: John Moore/Associated Press
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- Copyright © 1998 Discovery Communications
Inc.
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