Octopuses, Some Squid Edit RNA Sequences to Adapt to Environment
Author: Jonny Lupsha, News Writer
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Octopus and squid make strange evolutionary shortcuts in adaptation, Science Alert reported. Research shows that they may edit their own RNA in order to become accustomed to their environments. Evolution is an intricate process.
According to Science Alert, species of squid and octopus may yet have some surprises in store for us. “In a surprising twist, scientists discovered that octopuses, along with some squid and cuttlefish species, routinely edit their RNA (ribonucleic acid) sequences to adapt to their environment,” the article said.
“When an organism changes in some fundamental way, it typically starts with a genetic mutation—a change to the DNA. Those genetic changes are then translated into action by DNA’s molecular sidekick, RNA.”
The article said it’s very rare that RNA takes the first step, but octopuses and squid are an exception to the rule. DNA changes are almost always the beginning of the evolutionary process.
Demystifying Evolution
One popular misconception about evolution is that humans descended from monkeys. This is not the case. In order to take the first step on the right path in understanding evolution, it’s important to properly define it.
“A good definition that we can use for evolution is ‘change in the genetic structure of a population,’” said Dr. Barbara J. King, Chancellor Professor of Anthropology at William & Mary in Virginia. “All humans belong to a single species; we are all Homo sapiens. There are, however, multiple populations—groups of humans in which most mating takes place.”
Dr. King pointed out that the species level is the umbrella concept of a creature, and underneath it there are multiple populations, or pockets, of humans living around the globe. In other words, she said, there’s no meaningful category of humans between the population level and the single species level.
She also said that an older model of a population used to state that the only way in or out of one group of a species was birth and death, respectively. However, scientists have expanded this school of though to include immigration into the population and emigration out of it.
How Evolution Happens
The process of evolution is often oversimplified. Although the organism most suited to change often survives, this isn’t the only factor at work. In fact, Dr. King said, there are four main mechanisms of change within gene pools.
“The primary, most important mechanism is the one called natural selection,” she said. “It is an idea closely related to another: differential reproductive success, [which] simply means that in any population of animals, some parents will be better at producing many healthy offspring than are other parents.”
The second mechanism of change is mutation, or a change in the structure of DNA—the actual sequence of how DNA is put together in a string. It may happen spontaneously or due to environmental causes, but it produces raw material upon which natural selection may act.
“Mechanism number three is gene flow,” Dr. King said. “Gene flow is simply the exchange of genes between populations. Populations are open and individuals may move between them; of course as the individuals move, so do their genes.”
Finally, the fourth mechanism of change in genes is known as genetic drift. Genetic drift is a change in the gene pool structure due to some kind of random event. As an example, Dr. King said to imagine a group of hominids, or human ancestors. Some smaller group of these hominids, like a family, may be off foraging on its own and fall prey to some kind of natural disaster like a volcano or an earthquake. With their lineage suddenly wiped out, the gene pool of the main hominid group changes abruptly.
Having said that, it seems that octopuses and some squid may be offering up a rare exception to the four accepted mechanisms of change in a gene pool. Further studies will shed light on this biological anomaly.
Dr. Barbara J. King contributed to this article. Dr. King is a Biological Anthropologist and Chancellor Professor of Anthropology at William & Mary in Virginia. She earned her BA in Anthropology from Douglass College, Rutgers University, and her MA and PhD from the University of Oklahoma.