Here\u2019s what you\u2019ll learn when you read this story:<\/p>\n
It may have fewer than many of the other sciences, but biology does have two dozen or so \u201crules\u201d\u2014broad generalizations about the behavior or nature and evolution.<\/p>\n<\/li>\n
Now, USC researchers want to add a new rule called \u201cselectively advantageous instability (SAI),\u201d which explores how instability can actually benefit a cell and a cellular organism.<\/p>\n<\/li>\n
The flipside of this \u201crule\u201d is that SAI can also be a key factor to things like disease and aging, so understanding this process could aid in exploration of those biological processes.<\/p>\n<\/li>\n<\/ul>\n
Across the sciences, rules and laws help us make sense of the world around us, whether applied to cosmic scales or subatomic ones. However, in the biological world, things are a bit more complicated. That\u2019s because nature is often full of biological exceptions, and so \u201crules of biology<\/a>\u201d are also considered broad generalizations rather than absolute facts that explain and govern all known life.<\/p>\n Some of these broad generalizations include things like Allen\u2019s Law, which dictates that body shapes in endotherms (warm-blooded animals) adapt to climatic conditions\u2014short and stocky helps retain heat in cold climates, while tall and lanky helps dissipate heat<\/a> in warmer ones. Another \u201claw,\u201d known as Bergmann\u2019s rule, states that species of a broadly distributed clade tend to be larger in colder climates and smaller in warmer ones (though of course, as with most biological rules, exceptions apply<\/a>).<\/p>\n Some two dozen or so rules currently exist<\/a> that describe all kinds of processes of the natural world, and now, researchers at the University of Southern California (USC) hope to add a new rule. At first glance, this new rule\u2014called \u201cselectively advantageous instability,\u201d or SAI\u2014seems to defy the underpinning assumptions of life<\/a> in general, and pushes against the current assumption that life craves stability and a conservation of resources.<\/p>\n While nature does tend toward stability (it\u2019s one reason why we see so many hexagonal shapes in the wild, including honeycombs and insect<\/a> eyes), USC molecular biologist John Towers argues that instability in biological components like proteins and genes can actually be helpful to cells. The study was published last week in the journal Frontiers in Aging<\/a>.<\/p>\n \u201cEven the simplest cells contain proteases and nucleases and regularly degrade and replace their proteins and RNAs, indicating that SAI is essential for life,\u201d Tower said in a press statement<\/a>. \u201cThis can favor the maintenance of both a normal gene<\/a> and a gene mutation in the same cell population, if the normal gene is favorable in one cell state and the gene mutation is favorable in the other cell state.\u201d<\/p>\n These states allow for greater genetic diversity, which in turn can make organisms more adaptable. Many cell components also favor a short lifespan, as this actually helps promote cell<\/a> health. This indicates that SAI in these components is a necessary biological function.<\/p>\n Of course, there are plenty of downsides to instability. This energy-requiring process of mutation instability can introduce deleterious cells that contribute to aging<\/a>, while also inducing other types of damage and dysfunction.<\/p>\n \u201cAging has proven to be difficult to define, but most definitions include an increased chance of death with age, and decreased reproductive fitness with age,\u201d the paper reads. \u201cSAI can create a cost for the replicator in terms of energy<\/a> and\/or materials, and this cost might be interpreted in terms of promoting aging.\u201d<\/p>\n