Theoretical origin of life: LUCA calculated (Introduction)

by David Turell , Thursday, August 08, 2024, 17:04 (107 days ago) @ David Turell

Very early appearance:

https://www.nature.com/articles/s41559-024-02474-w

"Our results indicate that the LUCA existed between 4.09 and 4.33 billion years ago, a few hundred million years after the moon-forming impact. Our reconstruction of the genome of the LUCA is over 2.5 megabases, comparable to living bacteria, and encompasses at least 2,500 protein-coding genes. The LUCA was capable of nucleotide and protein synthesis, possessed a cellular envelope, and used ATP as an energy currency. … We also found that the LUCA possessed an RNA-based immune system … LUCA must have been part of a broader ecosystem, of which it represents the only living descendant. (my bold)

"Although some aspects of our study are in good agreement with previous work on the LUCA, we infer a larger genome size and genetic repertoire than most previous studies."

From a Washington Post article:

https://archive.is/FyGo8#selection-529.0-532.0

"Although Earth was formed nearly 4.6 billion years ago, scientists think our planet wasn’t cool enough for habitable environments until about 4.3 to 4.4 billion years ago, said Goldman. If LUCA was indeed around 4.2 billion years ago, as the study suggests, this dating would rewrite our understanding of how fast life can emerge under the right conditions.

“That is a lot of evolution to happen within 100 million years or less,” Goldman said. (my bold)

***

"The new timeline and details can be chalked up to more advanced analysis methods available today. In the new study, the team of 19 scientists used a combination of genetic analysis and fossil records to determine the age of LUCA and its characteristics. They first compared genes in modern genomes of bacteria and archaea to determine which gene families were present in LUCA. They estimated LUCA’s genome size, the number of proteins it encoded and its metabolism.

“'The computational model is kind of working its way backwards to say that these things are slightly different and, based on our model of molecular evolution, they probably share a common ancestor,” Moody said. “You work all the way back and eventually you’re going to get a common ancestor of everything, which is LUCA.'”

"The team separately performed an analysis using a much smaller number of genes that they thought duplicated before LUCA, which they calibrated with fossils to get its age.
Moody said the research is probably the “most ambitious” attempt to characterize and date LUCA.

***

"...new research released Monday suggested that organisms around that time could have received the necessary ingredients for life through lightning hitting the ground. Mimicking cloud-to-ground lightning in a lab experiment, scientists found that carbon and nitrogen in the air were converted into biologically useful molecules in high enough concentrations to spark or sustain life on Earth at that time.

"Haihui Joy Jiang, lead author of Monday’s study and a researcher at Harvard University, didn’t comment if her study supported this new LUCA theory but said this energy source could have been in play more than 4 billion years ago. That date matches up with the revised age of LUCA."

Comment: early life all based on theoretical estimates. An immune system of course implies an ecosystem that it lived in and reacted in. The comment: "That is a lot of evolution to happen within 100 million years or less" is a highlight of the suggestion there must be a designer. Life requires a complex entity to achieve actual living. Such sudden appearance of life begs for a designer.