Year: 2022

THEORETICAL PROTEIN POSSIBILITIES. “A biological protein can range from perhaps fifty amino acids long to several thousands. A typical length is three hundred amino acids long. Then let us consider all possible proteins that are two hundred amino acids in length. How many are possible? Each position in the two hundred has twenty possible choices of amino acids, so there are 20 × 20 × 20 . . . 200 times, or 20 to the 200th power, which is roughly 10 to the 260th power possible proteins of 200 amino acids in length.” https://lnkd.in/euEN3Eh View in LinkedIn

ACTUAL PROTEINS. “Now let us ask if the universe can have created all these proteins since its inception 13.8 billion years ago. There are roughly 10 to the 80th particles in the known universe. If these were doing nothing, ignoring space-like separation, but making proteins on the shortest timescale in the universe, the Planck timescale of 10 raised to the −43 seconds, it would take 10 raised to the 39th power times the lifetime of our universe to make all possible proteins of length 200, just once.” https://lnkd.in/euEN3Eh View in LinkedIn

LIMITS OF TIME. “In short, in the lifetime of our universe, only a tiny fraction of all possible proteins of length 200 can have been created. This means profound things.” https://lnkd.in/euEN3Eh View in LinkedIn

UNLIMITED LIMITS. “Not only will we not make all possible proteins of length 200 or 2000, we will not make all possible organs, organisms, social systems, . . . There is an indefinite hierarchy of non-ergodicity as the complexity of the objects we consider increases.” https://lnkd.in/euEN3Eh View in LinkedIn

SATURABLE OPTIONS. “Convergent evolution, which happens often, and concludes that the space of phenotypes is “saturable” and has been quite saturated by evolution.” https://lnkd.in/euEN3Eh View in LinkedIn

STARTING POINT. “It seems that many systems both increase their complexity if initialized in a low complexity state, and then reliably and robustly maintain high (but finite) complexity once it is attained. Some of the most prominent examples are the many biological systems undergoing natural selection that seem to start with low complexity and then increase their complexity.” https://lnkd.in/euEN3Eh View in LinkedIn

LOW COMPLEXITY START. “Such systems are typically modeled as localized individuals that reproduce in an error-prone process, with their offspring weeded out in competitions with other individuals that select for higher complexity. In this natural selection process the individuals in a line of biological descent increase their complexity in time.” https://lnkd.in/euEN3Eh View in LinkedIn

CAVEAT. “We should not confuse the properties of an example of a phenomenon with the phenomenon itself: complexity increase is not synonymous with adaptionist natural selection.” https://lnkd.in/euEN3Eh View in LinkedIn

PROGRESSIVE PROCESS. “Evolution is cumulative, for it has “the power to build new progress on the shoulders of earlier generations of progress”. https://lnkd.in/euEN3Eh View in LinkedIn

FRAGMENT FROM NATURE: this meditation considers viral hybrid swarms and quasispecies, which cloud traditional thinking about species. As usual, viral entities thumb their noses at biological norms, and on the topic of species, it is a spectacular thumbing. Viruses challenge biologists to rethink many old assumptions. View in LinkedIn