Month: September 2022

RELEVANT EXAMPLE. "In Japan and eastern Europe, species in two rodent lineages have completely eliminated the Y chromosome and replaced SRY with a different gene on a different chromosome. In each lineage the Y-less rodents have recently diverged into three species." https://lnkd.in/ehjz378 View in LinkedIn

FRAGMENT FROM NATURE touches on the controversial Virus First Hypothesis for the evolution of life. Much of this Fragment quotes a documentary on the topic, and a later Fragment will focus on related academic publications. The history of science is replete with examples of heretical ideas that were condemned by other scientists, but later became mainstream. Many scientists hate new ideas. View in LinkedIn

VIRUS FIRST VIEWPOINT. “There are actually relatively few formally-trained evolutionary scientists who will accept the virus-first perspective. I’ve encountered a couple. I’m immersed in a population of traditional evolutionary biologists here at Irvine. They just dismiss it. They don’t even want to think about it. So it’s not a prevailing perspective.” https://lnkd.in/ej7yCCq View in LinkedIn

RNA JUMBLE SALES. “According to his theory, dubbed the Virus World, the ancestors of modern viruses emerged when all life was still a floating stew of genetic information, amino acids, and lipids. The earliest pieces of genetic material were likely short pieces of RNA with relatively few genes that often parasitized other floating bits of genetic material to make copies of themselves. These naked pieces of genetic information swapped genes at a primeval genetic flea market, appropriating hand-me-downs from other elements and discarding genes that were no longer needed.” https://lnkd.in/eXmJ-Tt View in LinkedIn

STREAMLINING AND OURSOURCING. “Over time, Koonin argues, the parasitic genetic elements remained unable to replicate on their own and evolved into modern-day viruses that mooch off their cellular hosts. The genes they parasitized began to evolve different types of genetic information and other barriers to protect themselves from the genetic freeloaders, which ultimately evolved into cells.” https://lnkd.in/eXmJ-Tt View in LinkedIn

RNA WORLD. “The Virus World Theory is closely related to the RNA World Theory, which says life first evolved as small pieces of RNA that slowly developed into complex DNA-carrying organisms. The Virus World Theory agrees that life's genetic material began as RNA. But it differs by arguing that the ancestors of viruses evolved before cells.” https://lnkd.in/eXmJ-Tt View in LinkedIn

VIRAL WORLD AND DIVERSITY. “Supporters point to a few lines of evidence. First, the diversity of viruses far exceeds that found in cellular life. "Where diversity lies, origin lies.” https://lnkd.in/eXmJ-Tt View in LinkedIn

DIVERSITY PATTERNS. “According to this perspective, if viruses developed from cells, they should be less diverse because cells would contain the entire range of genes available to viruses. It's a recurring theme in evolutionary biology: One of the reasons we know humans originated in Africa is that genetic diversity among residents of that continent is much greater than it is anywhere else. If this pattern of diversity is true for humans…there's no reason it can't also be true for viruses.” https://lnkd.in/eXmJ-Tt View in LinkedIn

DIVERSE REPRODUCTION. “Viruses are also more diverse when it comes to reproduction. "Cells only have two main ways of replicating their DNA," said Patrick Forterre, a virologist at Paris-Sud University. "One is found in bacteria, the other in Archaea and eukaryotes." Viruses, on the other hand, have many more methods at their disposal.” https://lnkd.in/eXmJ-Tt View in LinkedIn

NUCLEAR VIROGENESIS. “I personally find the general idea that a nucleus is functionally equivalent to a selfish DNA virus (that is, replicating 'its' DNA using the cellular metabolism) simple and very appealing - and even more so when one realizes that the idea can be turned on its head to envisage the nucleus of a (primitive) eukaryote (re-)turning into a large DNA virus - the notion of nuclear viriogenesis.” https://lnkd.in/eyzfrxe View in LinkedIn