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Octopus genome sequenced
Genetic analysis sheds light on the evolution and unique biology of octopuses, including the development of complex nervous systems, writes EurekAlert.
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.
Octopus shows unique social and sexual behavior
The creature, known as the larger Pacific striped octopus, also turns out to be among the most gregarious of known octopuses. While most species are solitary, these have been seen in groups of up to 40 off the Pacific coasts of Nicaragua and Panama.
And while male octopuses typically share sperm with females at arm's length, ready to flee should the female get aggressive or hungry, mating pairs of this octopus when observed in captivity sometimes cohabit in the same cavity for at least a few days while mating, with little indication of escalated aggression. Mating pairs have even been observed to share meals in an unusual beak-to-beak position.
They do engage in rough sex, however. The pair grasp each other's arms sucker-to-sucker and mate beak-to-beak, as if kissing. The females mate frequently and lay eggs over several months, whereas the females of most known octopuses die after a single brood.
Octopuses are fascinating creatures that can even walk on land. Some studies have also suggested they're quite intelligent.
(Score: 5, Interesting) by carguy on Friday August 14 2015, @01:08AM
From http://www.tengerresearch.com/learn/interviews/jeromelettvin_text.htm [tengerresearch.com]
I had a pet octopus when I was in Naples. He was a big one, a huge one. "Juvenile Delinquent" is what I called him. My son Jonathan would play with him. We'd come into the lab in the morning and the octopus would be waiting for us. Jonathan would climb into the tank, and instantly there would be a tug of war, back and forth.
People talk about animals not having a sense of humor, this octopus knew how to play practical jokes, and it was wonderful to watch. My octopus would play practical jokes: "What do you mean an octopus playing practical jokes?!" you say. But it's true.
I teased JD — he was a big octopus, he had a 5 foot spread of arms — I teased him by holding a fish down for him to grab, then pulling it back [laughs]. JD would start going black-white-black-white indicating a high degree of irritation. Then JD decided to play a joke on me. Let me tell you, anybody who says octopus's don't have a sense of humor... forget it; they're good.
The next morning I walk into the lab and JD is up on the edge of his 20 foot tank. I walk in and smack! ... right in my face... he let out a huge squirt of water! He had been waiting for me to come in. Jonathan is in stitches, and then Jonathan says, "Take a look!" and I turn around and there are splotches of water all around the region of where my head would be when I come in. The octopus had planned his revenge and he had been practicing ahead of time. That sounds like a ridiculous story, eh? Well, it isn't.
It's a very different science that I teach.
Don't know about Jerome Lettvin? https://en.wikipedia.org/wiki/Jerome_Lettvin [wikipedia.org]
(Score: 2) by hemocyanin on Friday August 14 2015, @04:53AM
Octopi have honorary mammal status: https://soylentnews.org/comments.pl?sid=8979&cid=222682#commentwrap [soylentnews.org]
I don't miss bacon. I don't miss steak. I do miss octopus sushi.