{"id":10481,"date":"2023-11-09T10:00:00","date_gmt":"2023-11-09T10:00:00","guid":{"rendered":"https:\/\/modernsciences.org\/staging\/4414\/?p=10481"},"modified":"2023-10-27T07:38:57","modified_gmt":"2023-10-27T07:38:57","slug":"physics-has-long-failed-to-explain-life-but-were-testing-a-groundbreaking-new-theory-in-the-lab","status":"publish","type":"post","link":"https:\/\/modernsciences.org\/staging\/4414\/physics-has-long-failed-to-explain-life-but-were-testing-a-groundbreaking-new-theory-in-the-lab\/","title":{"rendered":"Physics has long failed to explain life \u2013 but we\u2019re testing a groundbreaking new theory in the\u00a0lab"},"content":{"rendered":"\n
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\n \n Daniel X D\/Shutterstock<\/a><\/span>\n <\/figcaption>\n <\/figure>\n\nLee Cronin<\/a>, University of Glasgow<\/a><\/em><\/span>\n\n

Modern physics can explain everything from the spin of the tiniest particle to the behaviour of entire galaxy clusters. But it can\u2019t explain life<\/a>. There\u2019s simply no formula to explain the difference between a living lump of matter and a dead one. Life seems to just mysteriously \u201cemerge\u201d from non-living parts, such as elementary particles. <\/p>\n\n

Assembly theory is a bold new approach to explaining life on a fundamental scale, with its framework recently published in Nature<\/a>. It assumes that complexity and information (such as DNA) are at the heart of it. The theory provides a a way to understand how these concepts emerge in chemical systems. <\/p>\n\n

Emergence is a word physicists use to explain something that is bigger than the sum of its parts \u2013 such as how water can feel wet when individual water molecules don\u2019t. Wetness is an emergent property.<\/p>\n\n

While the mathematics is elegant, the theory can ultimately only be reliable if it is tested in the lab. Carefully designed experiments, such as the one my colleagues and I are carrying out right now, will be essential to ground the abstractions of assembly theory in chemical reality.<\/p>\n\n

At the core of assembly theory is the idea that objects can be defined not as immutable entities, but by the history of how they formed. This shifts focus to the processes by which complex configurations are constructed from simpler building blocks. <\/p>\n\n

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\n Building blocks can be assembled much like lego to create molecules of life.<\/span>\n Image credit Dr Anna Tanczos, Sci – Comm Studios.<\/span>, CC BY-SA<\/a><\/span>\n <\/figcaption>\n <\/figure>\n\n

The theory proposes an \u201cassembly index\u201d which quantifies the minimal steps<\/a>, or shortest path, required to build an object. This measure tracks the degree of \u201cselection\u201d necessary to yield an ensemble of objects \u2013 referring to the memory, such as DNA, required to create living things.<\/p>\n\n

Living things, after all, don\u2019t just occur spontaneously, such as helium in stars. They require DNA as a blueprint for creating new versions.<\/p>\n\n

Predictions of novelty<\/h2>\n\n

But how might these theoretical constructs actually be probed experimentally?\nOne key aspect of assembly theory has already been tested in our lab<\/a>. That is the determination of the assembly index using mass spectrometry (an analytical tool which can measure the mass-to-charge ratio in molecules). <\/p>\n\n

By fragmenting molecules and analysing their mass spectra, we can estimate their assembly index. We can literally see how many steps it takes for various fragments to piece together to form a given molecule. Assembly index can also be measured using other techniques called infrared spectroscopy and NMR spectroscopy for various types of molecules.<\/p>\n\n

We\u2019ve determined the assembly index on a range of molecules, both in the lab and computationally. Our work shows that molecules associated with life, such as hormones and metabolites (products of metabolic reactions), are indeed more complex and require more information to assemble than molecules that are not uniquely associated with life, such as carbon dioxide. In fact, we\u2019ve shown that an assembly index above 15 steps is only found<\/a> in molecules associated with life \u2013 just as the theory suggests.<\/p>\n\n