Simple animals are not so simple after all
"Trends in Genetics", Dec. 2005
discovery is already altering the way that scientists view the evolution of animal genomes http://www.sars.no/research/technauPress.php
Corals and sea anemones (the flowers of the sea), long regarded as merely simple sea-dwelling animals, turn out to be more genetically complex than first realised. They have just as many genes as most mammals, including humans, and many of the genes that were thought to have been “invented” in vertebrates are actually very old and are present in these “simple” animals. This turns on its head the idea that underlying the complexity of higher animals (e.g. humans) is genetic complexity.
“There is no correlation between the complexity of an animal, in terms of numbers of different cell and tissue types, and the number of genes that are present in its genome. It appears that the numbers and diversity of genes required to build a sea anemone or coral do not differ much from the number required to build a mouse or a human,” said David Miller.
Most of the genes needed in higher animals to instruct cells and tissues to adopt a particular fate are present also in these simple organisms. “In fact, a substantial number of genes that were previously thought to be vertebrate-specific inventions were revealed in our analysis, which shifts the origin of these genes back to at least 500 million years ago.”
“Our results emphasize the role of gene loss during animal evolution. It seems that much of the animal gene complement was in place before the cnidarians branched off from the rest of the animal kingdom more than 500 million years ago, and that the best-studied invertebrates have simply lost a large number of these genes,”
- что в принципе отвечает картине, описанной в предыдущем (через одно) сообщении: все основные современные гены уже присутствовали в кембрийских организмах.