Evolution: more advances related to more microRNA (Introduction)

by David Turell , Friday, December 16, 2022, 21:54 (707 days ago) @ David Turell

From octopus studies:

https://www.sciencedaily.com/releases/2022/12/221215130916.htm

"An international team led by researchers at Dartmouth College and the Max Delbrück Center (MDC) in Germany report in the journal Science Advancesthat octopuses are the first known invertebrates -- creatures that lack a backbone and constitute roughly 95% of animal species -- to contain a high number of gene-regulating molecules known as microRNAs. The genes of two octopus species show an increase in microRNAs -- which are linked to the development of advanced cells with specific functions -- over evolutionary time that has so far only been found in humans, mammals and other vertebrates.

"When combined with the known intelligence of octopuses, the findings provide crucial support for the theory that microRNAs are key to the evolution of intelligent life, said co-corresponding author Kevin Peterson, a Dartmouth professor of biological sciences. The nervous systems of octopuses and squids -- which both belong to a type of mollusk known as cephalopods -- evolved independently of vertebrates. Yet, the prevalence of microRNAs in both octopuses and vertebrates suggest a common role for the molecules in advanced cognition.

"'MicroRNAs are known as the 'dark matter' of the animal genome -- they don't make protein, but they regulate the expression of proteins," Peterson said, referring to the hypothetical form of matter thought to constitute most of the universe.

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"Peterson's research has shown that creatures such as placental mammals whose genes have increased in number and complexity over evolutionary time also exhibit increasing concentrations of microRNAs. On the other hand, organisms such as parasites have lost ancestral genes -- and microRNAs -- as they have become less complex.

"'In order to have new cognitive abilities and behaviors requires new cell types," Peterson said. "The two places you get this -- in placental mammals and cephalopods -- is also where we see these microRNA-expressed genes. Animals that don't seem to have changed very much in the past 500 million years don't have very many microRNAs.

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"This kind of intelligence potentially stems from microRNAs' role in diversifying cell function, said study co-author Bastian Fromm, a research group at the University of Tromsø in Norway who collaborates with the Peterson lab on its research and building the online microRNA database, MirGeneDB.

"Cells in complex organisms perform specialized tasks, which means surrounding cells need to be calibrated to carry out additional functions, Fromm said.

"'MicroRNAs are like light switches or dimmers that can turn on and regulate the expression of thousands of proteins in a cell and specify what the cell can do," Fromm said. "This is a numbers game. Oysters and slugs have microRNAs, but in cephalopods -- and especially the octopus -- there is an explosion of them that correlates with their intelligence.'"

Comment: MicroRNA's are 'control' switches as the article shows, Easy for God to dabble with that arrangement.