Lifeboat Foundation

Life’s evolutionary timescale is typically calibrated to the oldest fossil occurrences. However, the veracity of fossil discoveries from the early Archaean period has been contested^11,12. Relaxed Bayesian node-calibrated molecular clock approaches provide a means of integrating the sparse fossil and geochemical record of early life with the information provided by molecular data; however, constraining LUCA’s age is challenging due to limited prokaryote fossil calibrations and the uncertainty in their placement on the phylogeny. Molecular clock estimates of LUCA^13,14,15 have relied on conserved universal single-copy marker genes within phylogenies for which LUCA represented the root. Dating the root of a tree is difficult because errors propagate from the tips to the root of the dated phylogeny and information is not available to estimate the rate of evolution for the branch incident on the root node. Therefore, we analysed genes that duplicated before LUCA with two (or more) copies in LUCA’s genome¹⁶. The root in these gene trees represents this duplication preceding LUCA, whereas LUCA is represented by two descendant nodes. Use of these universal paralogues also has the advantage that the same calibrations can be applied at least twice. After duplication, the same species divergences are represented on both sides of the gene tree^17,18 and thus can be assumed to have the same age. This considerably reduces the uncertainty when genetic distance (branch length) is resolved into absolute time and rate. When a shared node is assigned a fossil calibration, such cross-bracing also serves to double the number of calibrations on the phylogeny, improving divergence time estimates. We calibrated our molecular clock analyses using 13 calibrations (see ‘Fossil calibrations’ in Supplementary Information). The calibration on the root of the tree of life is of particular importance. Some previous studies have placed a younger maximum constraint on the age of LUCA based on the assumption that life could not have survived Late Heavy Bombardment (LHB) (~3.7–3.9 billion years ago (Ga))¹⁹. However, the LHB hypothesis is extrapolated and scaled from the Moon’s impact record, the interpretation of which has been questioned in terms of the intensity, duration and even the veracity of an LHB episode^20,21,22,23. Thus, the LHB hypothesis should not be considered a credible maximum constraint on the age of LUCA. We used soft-uniform bounds, with the maximum-age bound based on the time of the Moon-forming impact (4,510 million years ago (Ma) ± 10 Myr), which would have effectively sterilized Earth’s precursors, Tellus and Theia¹³. Our minimum bound on the age of LUCA is based on low δ⁹⁸ Mo isotope values indicative of Mn oxidation compatible with oxygenic photosynthesis and, therefore, total-group Oxyphotobacteria in the Mozaan Group, Pongola Supergroup, South Africa^24,25, dated minimally to 2,954 Ma ± 9 Myr (ref. ²⁶).

Our estimates for the age of LUCA are inferred with a concatenated and a partitioned dataset, both consisting of five pre-LUCA paralogues: catalytic and non-catalytic subunits from ATP synthases, elongation factor Tu and G, signal recognition protein and signal recognition particle receptor, tyrosyl-tRNA and tryptophanyl-tRNA synthetases, and leucyl-and valyl-tRNA synthetases²⁷. Marginal densities (commonly referred to as effective priors) fall within calibration densities (that is, user-specified priors) when topologically adjacent calibrations do not overlap temporally, but may differ when they overlap, to ensure the relative age relationships between ancestor-descendant nodes. We consider the marginal densities a reasonable interpretation of the calibration evidence given the phylogeny; we are not attempting to test the hypothesis that the fossil record is an accurate temporal archive of evolutionary history because it is not²⁸.

Hybridizing OI and AI, and adding what seems like a “human” component into our current advances, probably asks more questions than it answers. Here are some of those questions for the law, and how we might begin to think about them.

The Best — and Worst — of Brains

Envisioning how brain organoids might entangle themselves with the law doesn’t take a wild imaginative step; many of the questions we might have around brain organoid models are similar to the ones we’re currently grappling with regarding artificial intelligence. Would OI warrant recognition for the work it produces? And is that output protectible? Under current (and quickly-evolving) copyright developments, AI doesn’t meet the “human” requirement for authorship on its own. But AI (and OI) require human input to work, and there may be some wiggle room on AI work protection, either citing AI as a joint author with human operators, or drawing a line at a certain threshold of human control in the AI-generated work as sufficient for copyright protection.

AGI by the end of the decade?

Ishida, T. Sci Rep 14, 2086 (2024). https://doi.org/10.1038/s41598-024-52475-9

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Scientists have combined real human brain tissue with electronics to make a new kind of biocomputer.

The breakthrough blends biological and mechanical elements, sparking ethical debates.

Sam Altman and Arianna Huffington told me that they believe generative AI can help millions of suffering people. I’m not so sure.

Researchers at Cornell University have designed a novel in-suit urine collection and filtration system, or “Dune” system,” to “promote astronaut wellbeing.”

Facepalm: Crashes experienced by customers owning recent high-end Intel processors aren’t just software or BIOS-related issues. Alderon Games founder Matthew Cassells says Chipzilla has made his company’s life much more complicated than it should be. The game developer has experienced considerable Intel CPU problems, including crashes, instability, and memory corruption.

The number of people and organizations forced to experience crashes and general instability on Intel’s latest CPU models keeps growing. Now, a game developer is blatantly pointing the finger at the Santa Clara corporation and its alleged “defective” products.

“Despite all released microcode, BIOS, and firmware updates, the problem remains unresolved,” Cassells said.