Coral reveals ancient origins of human genes
Invertebrate DNA raises questions about evolution models.
16 December 2003
CARINA DENNIS

A study of coral suggests that ancient members of the animal kingdom
slithered through the Precambrian mud with a hefty cache of genes in common
with humans.

Surprisingly, many of these genes are not shared with creatures such as
flies and worms, even though these animals evolved millions of years after
coral. This calls into question some studies that use these model organisms
to unravel the evolution of the human genome.

The investigation, published in this week's Current Biology1, looked at some
1,300 gene sequences expressed in the coral Acropora millepora, and found
that about 500 sequences had matches in gene databases. These sequences,
called expressed sequence tags, represent either single genes, different
pieces of the same gene, or expressed portions of DNA that do not contribute
to a coding gene.

Of these, 90% were present in humans, and about 10% were found in humans but
not in the fruitfly Drosophila melanogaster or the nematode worm
Caenorhabditis elegans. This finding suggests that many genes thought to be
vertebrate-specific may in fact have much older origins, and have been lost
during the evolution of the fly and worm

Read the rest at Nature
http://www.nature.com/nsu/031215/031215-2.html

Comment:
Haemoglobin can also be found in plants and some genes previously thought to
be vertebrate-specific have been found in the flatworm Schmidtea
mediterranea.

Posted by
Robert Karl Stonjek.
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