Subject: Whales, hippos, cows share anc (fwd by fred) (fwd)

mike williamson (williams@www1.wheelock.edu)
Thu, 21 Aug 1997 15:08:00 -0400 (EDT)

Subject: Whales, hippos, cows share anc (fwd by fred)

    TOKYO, Aug 14 (Reuter) - Although there might not be much of
a family resemblance, the whale, hippopotamus and common cow
share a common ancestor from about 60 million years ago,
Japanese researchers said on Thursday.
     In an article in the August 14 issue of the British
publication Nature, a team of scientists led by Tokyo Institute
of Technology faculty members say genetic evidence indicates the
three animals belong to the same common ancestoral form, known
as a monophyletic group.
     "Our data provide evidence that whales, ruminants (grass
chewers) and hippopotamuses form a monophyletic group," it
said.
     According to research team member Norihiro Okada, the common
ancestor was probably a terrestrial herbivore.
     Okada told Reuters the team looked at retroposons, a genetic
element that does not change as evolution progresses, to link
the three to the common ancestor.
     "The team used a novel and original approach toproduce
these highly significant results," Okada said of the research
that has given a number of species new ancestoral mothers and
fathers.
     The team said that about 100 million years ago, the three
were in a grouping that included pigs and camels, but whales,
cows and hippos derived from a separate ancestor some 60 million
years ago.
     "Whales are clearly related to cows and hippopotamuses, but
pigs and camels have different genetic elements," Okada said.
     The researchers said their findings contradict current
paleontological and morphological studies that indicate whales
first appeared as primitive aquatic creatures.
     The team also argues their findings should lead scientists
to reexamine fossil records because the discovery pushes back
the era when mammals diversified.
     While most research holds that mammals and birds diversified
after the extinction of dinosaurs about 65 million years ago,
that by the Japanese team indicates the change may have started
as early as 100 million years ago.