Tuesday, May 15, 2007

Corals - More complex than you?

I found this article to be quite a twist to what common evolution is all about. It gives an insight on genes that have supposedly been evolved over a long period of time, but have actually been there the entire duration. According to the current studies, corals have genes that are much more complex than anyone expected.

A recent study by the Coral Genomics group led by David Miller at James Cook University has discovered numerous genes found in corals that are shared with vertebrates. This comes to no surprise because corals are near the roots of trees for all living animals. Corals are hypothesized to have around 25,000 genes based on the current gene sequencing. Humans only contain around 20,000-23,000. Genome size cannot depict how complex an organism is, which is illustrated perfectly here. Corals appear to be very simple animals with no complex processes or organs. The part that I found to be interesting was that 10-12% of known coral genes are unique shared with vertebrates, which code for nerves, vision, DNA imprinting, stress responses and key parts of the immune system. Due to certain genes being ‘turned off’, only those ‘turned on’ or functional will code for proteins. Even though corals possess these genes, they are not completely functional because they are spliced out during development. Corals share these same genes with humans but humans have a much more ‘advanced’ immune system. Why is it that corals possess the genes to have more advanced systems (vision, immune) and not form them? Have humans truly evolved these genes by coincidence, or have they always been there as dormant (off) genes in direct human ancestors?

Scientists are now suspecting that corals have evolved these genes because of pandemic diseases they are currently facing, such as “white plague, white bands, or white pox”. The corals previously contained these genes but natural selection caused them to begin functioning. The genes are not all functioning completely, but there is evidence that natural selection has selected against the corals whose genes are inactive.

Animals that have very fast generation times tend to shed genes much faster than other animals, such as flies or insects. Corals have generation times which are much slower (around 5 years), making scientists believe that corals can be seen as a ‘museum’ of genes for animals. There is currently no project to sequence coral genome. Knowing what other genes could be found in corals may alter numerous previous beliefs of evolution and ancestry. Corals could possibly contain numerous other genes shared with humans, coding for development of much more complex systems.

-- submitted by Lucas Anderson.



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