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A.
New Genetic Analysis Shakes Up Salamanders' Family
Tree
Narrator: This is Science Today.
A new, genetic analysis of the largest family of
salamanders has pretty much shaken their family
tree. Rachel Mueller, a graduate student of Integrative
Biology at the University of California, Berkeley,
says the Plethodontid salamanders, a lungless group
that breathes through their skin, make up two-thirds
of the world’s known species of salamanders.
Mueller:
They’ve been studied quite a bit and all the studies
about them have assumed that we knew sort of the
four major groups of Plethodontids salamanders.
So, not only who was in each group, but also how
those groups were related to each other. And those
relationships were based primarily on bone data
– so we thought we’d just double check that bone
data with genetic data.
Narrator:
Mueller sequenced genetic data of these salamanders
at the UC-operated Joint Genome Institute, which
played a big part in helping decode the human genome.
Mueller:
We ended up finding that actually three out of the
four groups weren’t actually groups at all. So,
it definitely is a hint that in many cases, we’re
underestimating greatly the biodiversity in species
where we haven’t looked at them genetically just
because they look very similar to one another.
Narrator:
For Science Today, I’m Larissa Branin.
B.
The Conflicting Data about Virtual Colonoscopy
Narrator: This is Science Today.
Colon cancer is the second leading cause of cancer
death in the United States. There are several screening
options available – colonoscopy being the gold standard
test, but over the years, virtual colonoscopy – a
less invasive procedure – has gained in popularity.
Ladabaum:
Virtual colonoscopy has been in development for the
last several years. Most recently, there have been
some technical advances that have suggested that this
test may actually be quite good at detecting colorectal
cancers and polyps, but the published data have been
conflicting.
Narrator:
Dr. Uri Ladabaum of the University of California,
San Francisco recently conducted a national study
using data from conflicting studies of the two colonoscopy
procedures and concluded that virtual colonoscopy
is not ready for widespread use.
Ladabaum:
The initial studies that were very promising tended
to be in patients who had a high rate of polyps and
cancer and often, tests look better when you have
a population that is enriched with pathology. So what
many of us were waiting for were studies in a general
population at average risk.
Narrator:
For Science Today, I’m Larissa Branin.
C.
Adolescent Obesity: An Issue of Energy Intake &
Expenditure
Narrator:
This is Science Today. Childhood and adolescent obesity
has been increasing dramatically over the last generation
and a lack of vigorous activity is a primary factor
in this trend. Dr. Kevin Patrick, a professor of family
and preventive medicine at the University of California,
San Diego’s School of Medicine, says adolescent obesity
is an issue of energy intake and energy expenditure.
Patrick:
With respect to the expenditure of energy, the two
clusters of considerations relate to how active kids
are and how sedentary they are.
Narrator:
From a research standpoint, Patrick says
the understanding of activity and sedentary behaviors
differ.
Patrick:
Physical activity is a really different behavioral
construct than a sedentary behavior and when we think
about working with kids and families and settings
from the school to the communities to clinical settings,
we have to recognize that there really are different
sorts of approaches that have to be taken, but they’re
all part of this big equation of energy balance and
that’s really the important thing that seems to have
gone awry, over the last twenty years or so.
Narrator:
For Science Today, I’m Larissa Branin.
D.
The Largest Ethanol-Powered Fleet in California
Narrator:
This is Science Today. Ethanol is an alternative fuel
produced from agricultural bio-mass products such
as corn or soybean and it’s being used to power 60
vehicles at the University of California-managed Lawrence
Berkeley National Laboratory. Dan Prestella, the Lab’s
fleet operations supervisor, says this makes their
onsite motor pool the largest ethanol-powered fleet
in the Golden State.
Prestella:
This station has been about three years in the making.
We put in for a grant through the DOE in early 2002
and we were able to get enough funds to do this and
we identified ethanol as our product of choice to
meet our alternative fuel vehicle requirements.
Narrator:
Prestella explains that an executive order asked all
federal agencies to make sure that 75% of their replacement
vehicles use alternative fuel to reduce air emissions.
Prestella:
We have this above ground, four thousand gallon ethanol
tank and what it does is it feeds one of our new pumps.
A customer drives up to the pump in an ethanol powered
vehicle, inserts a key into a card reader, punches
in the mileage and then they pump just as you would
at a normal gas station.
Narrator:
For Science Today, I’m Larissa Branin.
E.
Better Think Twice Before You Skip Breakfast
Narrator:
This is Science Today. Have you ever thought that
skipping breakfast would be an easy way to cut back
calories? Well, a nationwide study out of the University
of California, Berkeley, has found that skipping breakfast
is actually bad for keeping off weight. Nutritional
epidemiologist, Gladys Block, explains.
Block: People might think that if
they skip breakfast that they're doing themselves
a favor, and in fact they're not. And in fact it was
interesting because the people who skip breakfast
actually had lower total energy, total calorie intake,
and yet they had much higher body mass index.
Narrator: Block says that skipping
breakfast represents disordered eating habits associated
with weight gain and that the nature of what you have
for breakfast also makes a big difference.
Block: The people who had eggs and
bacon for breakfast were the highest body weight actually,
whereas people who had breakfast cereal for breakfast
were among the lowest. So maybe the actual nature
of your breakfast makes a difference in addition to
eating it at all.
Narrator: For Science Today, I'm
Larissa Branin.
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