http://www.infobeat.com/stories/cgi/story.cgi?id=2560938864-06b
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Title: Full Story
05:16 PM ET 08/30/99
Gene Study Links Whales and Hippos
Gene Study Links Whales and Hippos
WASHINGTON (AP) _ One has no legs and swims in the ocean, and
the other has four legs and lives in rivers, but a genetic study
shows that the whale and the hippo are close relatives in
evolutionary history.
The study, by researchers at the Tokyo Institute of Technology
in Japan and Pennsylvania State University at University Park, Pa.,
compared gene sequences from the minke whale, the sperm whale and
the hippopotamus. It found the diverse animals share a sequence of
genes inherited from an ancient common ancestor.
A report of the study appears Tuesday in the Proceedings of the
National Academy of Sciences.
The study found that the camel, pig, giraffe, sheep and cow
share some gene sequences with the whale and hippo, indicating that
far back in time all had a common ancestor, according to evolution
theory. The animals diverged genetically. A gene sequence found
only in whales and the hippo show that they share a common ancestor
that was not part of the evolutionary history of the other animals.
Until 1985, it was generally thought that pigs were more closely
related to whales. Other genetic studies since have suggested the
whale-hippo link. The new study, researchers say, confirms that the
hippo is the closest living relative to the whale.
The genetic analysis was conducted by Masato Nikaido and
Norihiro Okada of the Tokyo Institute and by Alejandro Rooney of
Penn State.
It has long been believed that the whale's ancient ancestor was
a land animal. It is thought that a lineage leading to the modern
whale returned to the sea and evolved into a group of marine
mammals called cetacean. Along the way, hind legs were lost, and
forelegs were replaced by flippers.
David Hillis of the University of Texas, in a PNAS commentary,
said whales and hippos share several adaptations, including the
lack of hair and oil-producing skin glands, and the ability to
communicate and to nurse offspring under water.
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