Comparing genomes
10 December 2003 9:00 GMT
by Carrie Mollatt

About three billion As, Ts, Gs, and Cs make up the human genome sequence,
but other organisms that are only slightly simpler can have up to 1000 times
less DNA - implying that some human DNA is redundant, says Ewan Birney of
the European Bioinformatics Institute (EBI) in Cambridge, UK. So which
sections of DNA are redundant, he asks, and which sections correspond to
specific genetic traits?

The most challenging aspect of this question, says Birney who heads Ensembl,
an EBI project set up to develop software to facilitate annotation of the
growing volume of data on eukaryotic genomes, is how to search for genes in
the human genome when it is not clear what those genes look like.

Fortunately, he notes, there is an aspect of genetics and evolution that
researchers can take advantage of when trying to solve the problem. All
organisms alive today are genetically similar to a certain extent, because
the 'original genome' from which they evolved would have had a specific set
of genes. Genes that were correctly transferred over generations would be
conserved over time and thus everything that is known about the genetics of
every organism that has ever been studied can be used to help understand the
human genome.

This is where the work of Birney's group comes in. Data generated by groups
in Europe, the US and Japan are shared to update the Ensembl database with
the latest information on each eukaryotic genome (including rat, Drosophila
and C. elegans), providing an invaluable tool for researchers in the field.

Read the rest at BioMedNet
http://gateways.bmn.com/news/story?day=031211&story=1

Comment:
Wheat has considerably more DNA then humans (16 Billion base pairs compared
to human's 3 billion).

Bees are no bird-brains
9 December 2003 14:00 GMT
by Henry Nicholls

When it comes to judging cognitive ability, neuroscientists are guilty of
prejudice against invertebrates, argues an expert in honeybee cognition. Bee
brains are capable of much more than is assumed, he claims.
"We have this kind of prejudice that insects or invertebrates are
essentially stupid," said Martin Giurfa, a neuroethologist at the Center for
Research on Animal Cognition in Toulouse, France. Because of this,
researchers are failing to ask the right questions of invertebrates, he
says. But the cognitive abilities of the honeybee, one of the best studied
insects, are showing that insects and possibly other invertebrates can
perform some quite advanced mental tasks.

The current cognitive champion of the invertebrate world is the honeybee,
says Giurfa. With fewer than a million neurons and a volume of just 1 cubic
millimeter, the honeybee brain has "well developed learning and memory
capabilities, whose essential mechanisms do not differ drastically from
those of vertebrates," he notes in a special issue of Current Opinion in
Neurobiology.

For example, a complex odor comprised of several compounds triggers neural
correlates of each of the separate elements that make up the smell, says
Giurfa. But there is also "a special kind of signature for this and only
this mixture that could tell the brain that there is something more than
just the elements," he said. "It is clear that something is going on in the
mini brain of the honeybee that is more than just a sum of the stimuli."

A common explanation for the advanced nature of the honeybee brain is that
selection imposed by the need to be social has driven the evolution of the
insect's nervous system.

http://gateways.bmn.com/news/story?day=031210&story=1

In the eye of the beholder
8 December 2003 8:00 GMT
by Laura Nelson

Disagreement over evolution of the eye could be settled with a new
hypothesis that its author claims unites two opposing hypotheses - that all
animal eyes evolved from a single original eye, and that different species'
eyes evolved independently from multiple origins.
Todd Oakley, assistant professor of biology at the University of California,
Santa Barbara, suggests that eye duplication is the key. An eye might
duplicate itself, but the second genetically-identical eye could end up
located in a different position to the original eye. The duplicated eye
could then evolve independently into a distinct structure.

Oakley is the first to suggest this idea for eyes, but he notes that a
similar theory has previously been proposed for other structures, including
limbs. "It is a general idea in evolution," he said. Extending the idea to
eyes could end what he refers to as a "scientific war."

But other researchers who work on eye growth and development are not even
convinced there really is a controversy. Some accuse Oakley of creating a
"false dichotomy."

http://gateways.bmn.com/news/story?day=031209&story=1

Comment:
Pax-6, common gene to all eye development, also mediates olfactory and brain
development.

Posted by
Robert Karl Stonjek.
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