The Hindu (August 5, 2010)
"What is so unique about sea sponges that scientists should care to sequence its genome? Simply put, sea sponges are considered the oldest surviving species of the multicellular metazoan lineage.
"Hence studying their DNA can help in identifying the genetic innovations that enabled transition from single-celled to multicellular life (metazoan animals) some 600 million years ago. Metazoan animals make up a major portion of the animal kingdom.
"Not 'true animals'
"Sea sponges do not have a gut and nervous system, and are hence not generally considered as 'true animals.' Yet, scientists are of the opinion that other multicellular metazoan animals evolved from sponge-like ancestors...."
A close look at the sea sponges' genes showed a "developmental toolkit" that could have let them develop muscles and nerves - although they don't.
I was impressed that sea sponges are genetically similar to other multicellular animals, even though they branched off from the rest more than 600,000,000 years back. It seems to be another case of 'things happened earlier.'
Related posts:
- "Four Legs, a Tail, and Tracks a Third of a Billion Years Old"
(July 26, 2010) - "Early Humans: Climbing/Walking Tradeoff Pushed Back"
(April 30, 2009) - "Something Was Crawling on the Precambrian Mud"
(February 19, 2010)
Related posts, at
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