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basstard [soylentnews.org] writes:

Genetic analysis sheds light on the evolution and unique biology of octopuses, including the development of complex nervous systems, writes EurekAlert. [eurekalert.org]

The first whole genome analysis of an octopus reveals unique genomic features that likely played a role in the evolution of traits such as large complex nervous systems and adaptive camouflage. An international team of scientists sequenced the genome of the California two-spot octopus - the first cephalopod ever to be fully sequenced - and mapped gene expression profiles in 12 different tissues. The findings are published in Nature on Aug 12, 2015.

The researchers discovered striking differences from other invertebrates, including widespread genomic rearrangements and a dramatic expansion of a family of genes involved in neuronal development that was once thought to be unique to vertebrates. Hundreds of octopus-specific genes were identified, with many highly expressed in structures such as the brain, skin and suckers.

[...]

The team estimates the O. bimaculoides genome is 2.7 billion base-pairs in size, with numerous long stretches of repeated sequences. They identified more than 33,000 protein-coding genes, placing the octopus genome at slightly smaller in size, but with more genes, than a human genome.

The large size of the octopus genome was initially attributed to whole genome duplication events during evolution, which can lead to increased genomic diversity and complexity. This phenomenon has occurred twice in ancestral vertebrates, for example. However, Ragsdale and his colleagues found no evidence of duplications.

Original Submission