SCIENCE IN THE NEWS in VOA Special English.
I'm Bob Doughty.
I'm Barbara Klein. This week, we will
tell about a genetic study of one of the world's most unusual animals. We will tell about a health threat to cattle
and the people who eat their meat. And,
we share findings from a new report about a famous circle of stones in southern
An international team of researchers
says it has completed a genetic map for an unusual-looking animal: the
platypus. For years, scientists have
been interested in the platypus because it appears to be a mix of several
different animals. The platypus has
hair covering its body. But it also has
a bill surrounding its mouth and webbed feet like a duck.
researchers sought to understand how this strange creature developed by
studying its genome, or full set of chromosomes. The new, genetic map shows that the platypus has genes also found
in both birds and reptiles. The
research team reported its findings last month in the publication Nature.
platypus is native to eastern Australia.
The platypus is not endangered; however, people rarely see them. This is because the animals spend much of
their time in underground passages along small rivers.
the platypus is considered a mammal, it is actually one of two animals known as
monotremes. Both the platypus and the
echidna are believed to have resulted from other mammals. Scientists believe this separation from more
traditional mammals took place more than one hundred sixty million years ago.
The platypus is so unusual that when it
was first sent to scientists in Europe in the nineteen century, they thought
the animal was a joke.
For the new study, the researchers
examined genetic material from a female platypus they call Glennie. She lives in southeastern Australia. A goal of the study was to find which
platypus qualities came from ancient reptiles, and which resulted separately in
the development of monotremes.
researchers found that the platypus genome includes some genes not found in
other mammals. For example, it includes
genes linked to production of eggs.
These genes are shared only with reptiles and fish. The platypus also has genetic material for
poisonous venom production similar to that of snakes. The venom is found in back legs of male platypuses. The animal uses it to attack its enemies or
platypus also carries mammalian genes for milk production. The animal does not have nipples, like most
mammals, to feed its young. Instead,
the platypus feeds milk to its young through skin on its abdomen.
the surprises the research team discovered was genetic material responsible for
sensitive odor receptors. Scientists
had already known of the platypus' ability to identify electric fields of other
animals underwater. The researchers
believe the platypus uses the odor smelling ability to find its way underwater,
for communication used in mating, or to hunt.
study also found that the platypus genome is two-thirds the size of the human
genome. Eighty-two percent of the
animal's genes are shared with mammals.
tuberculosis is a progressive wasting disease.
It affects mainly cattle but also sheep, goats, pigs and other
animals. People who get bovine TB have
to take strong antibiotics for up to nine months to cure them.
can get sick from infected cows by drinking milk that has not been heated to
kill germs. Another risk is eating meat
that has not been cooked to seventy-four degrees Celsius. If an infected animal is processed, cutting
through lung or lymph tissue can spread the M. bovis bacteria to other parts of
TB is a major problem in parts of Africa.
Farmers in Canada and Britain have also lost many cattle in recent
years. In Britain, debate continues
about whether badgers pass TB to other animals.
cows might lose weight and develop a cough.
The bacteria can spread from the sudden expulsion of air from the
lungs. Or infected animals can appear
healthy. Then, when they give birth,
their milk can pass the infection to their young.
the early twentieth century, bovine TB probably killed more animals in the
United States than all other diseases combined. To control it, the government launched a successful testing
program. Historians say animal doctors
ordered the destruction of about four million cattle between nineteen seventeen
and nineteen forty.
American state of Michigan has been fighting tuberculosis in cattle. Experts identified wild deer as the source
of infection. The neighboring state of
Minnesota and the western state of California have also had to deal with TB in
cattle and deer.
and wild deer can infect each other -- for example, if they share cattle feed
left in fields during winter. Possible
solutions might include building fences or leaving smaller amounts of hay.
say the most effective form of control is to destroy cattle herds that have
been exposed to bovine tuberculosis.
This prevents any chance that infected cows might be moved to another
In April, the United States Department
of Agriculture announced the availability of nearly seventeen million dollars
in emergency assistance. The Department
said the money is meant for programs to fight bovine TB in California, Michigan
states are to use the money to destroy cattle herds shown to have
tuberculosis. The aid could also be
used to study the affected groups and identify the cause of infection.
new research suggests that England's Stonehenge served as a burial ground for hundreds
of years. Stonehenge has long been of
interest to archeologists and the public.
Thousands of people visit the area each year.
In the past, archaeologists thought that
burials at Stonehenge continued for only about one hundred years. Studies had shown human remains were buried
there between four thousand six hundred and four thousand seven hundred years
ago. That is about a century before the
famously large stones were placed there.
tests of human remains show burials instead took place at Stonehenge over a
period of about five hundred years.
Researchers used radiocarbon dating tests to estimate the age of the
remains. The researchers say the burials
began there as early as three thousand years B.C., or about five thousand years
latest burial discovered was identified as a woman in her twenties. Her remains date back to around four
thousand five hundred years ago. That
is around the same time period when the huge stones, also known as sarsen, were
latest research marked the first radiocarbon dating of human remains from the
Stonehenge area. Scientists believe
that as many as two hundred forty people were buried in the area. All of the human remains found there were
burned before being buried in the ground.
Parker Pearson is an archaeology professor at the University of Sheffield in
England. He is also the head of the
Stonehenge Riverside Project. The
project is a seven-year archaeological investigation of Stonehenge. The National Geographic Society provided
financial aid for the research. The
team's findings are published this month in National Geographic magazine.
Parker Pearson says that scientists continue to debate questions like who built
Stonehenge and why. He says evidence
supports the theory that the area served as a burial ground for a single ruling
family. He says thirty to forty
generations were buried there. The
number of remains grew over time. This
suggests one family in which each generation included more family members. Because of this, Mister Parker Pearson
believes it was not common people who were buried there. He says the remains are likely those of a
royal family or one that ruled over the area.
some scientists have other ideas about what the area was used for. They say that more research is needed.
SCIENCE IN THE NEWS program was written by Jerilyn Watson and Brianna Blake,
who also was our producer. I'm Bob
I'm Barbara Klein. Read and listen to
our programs at voaspecialenglish.com. Join us
again at this time next week for more news about science in Special English on
the Voice of America.