Henry Dawson reviews the microbial evidence that 'out in Nature' defectives quickly die out and finds it faulty, with gratifying results for all humanity

One of the most popular bromides among penny-pinching middle class intellectuals of the era of Panic Modernity (circa 1860s to the 1960s) was that without humanity's regrettable humanitarian social safety net, human 'defectives' would quick die out, as always happens 'out there' with Nature's defectives.

Dr Henry Dawson, born in 1896, had imbibed this certitude growing up but from his earliest days of independent scientific research he seemed to have doubted its validity.

Instead, he chose to focus on closely studying microbial 'defectives' and both studying and trying to help human 'defectives'.

And ten billion of us (and counting) since 1940 have had better lives because he choose to do so.

When questioned why harsh Evolution hadn't already weeded out all the defectives among homo sapiens during the hundreds and hundreds of thousands of years before the modern social safety net emerged, Darwin's bulldogs pointed out that Evolution worked very gradually and the numbers of individuals in the human species until quite recently was very low indicated that earlier, most defectives had indeed failed to reproduce.

But Dawson's lifelong fascination with microbial variation was really a study of surviving minority mutations, among wild populations that had been around for billions of years, and in numbers of actual defective individuals easily approached hundreds of thousands of billions of individuals.

Thus the maxim that 'Nature abhors Defectives' was hardly born out in the case of the microbes.

Evolution had greatly favoured the microbes over all other types of lifeforms as they survived all the 'die offs' that had continually wiped out almost all life over the four billion years of life on Earth.

Could the great width and depth of genetic diversity in the collective microbial gene pool have actually helped, rather than hurt, microbial survival in tough times ?

Consider that the relatively few individuals among the penicillium molds who actually produce penicillin in appreciable amounts are clearly 'defectives' in every sense of the word.

Secondary metabolites, biological products made that don't directly contribute to ongoing existence or reproduction, such as penicillin, are always an inefficient waste of scarce resources needed for basic survival.

Any individual that makes them instead of devoting all the raw resources consumed in doing so towards reproduction is thus usually going to dwindle in numbers among the wild population and thus usually become a minority.

But when times suddenly become tough and bacterial competitors edge in to eat the scarce bits of food the penicillium molds need for basic survival, those few mold individuals exuding deadly bacteria-killing penicillin suddenly have at better, not worse, chances to survive and reproduce.

Deadly ?? Did I say deadly ?? Because, as Dawson's lab first demonstrated, actually penicillin is a highly selective killer - only killing rapidly reproducing bacteria - which are ipso facto, the biggest competitors to starving molds.

Thanks to them, the overall penicillium mold species thus never totally die out.

But when abundant food returns, the metabolical extra drag of producing penicillin instead of more mold 'babies', again makes the penicillin-producing penicillium molds a minority again.

At least until the next crisis.

Another example --- again first demonstrated in Dawson's lab --- some defectives in the bacteria clan opposing the penicillium molds, also ensure the bacteria's survival when crisis - a stiff dose of penicillin - hits.

These defectives, the 'inverts' of the microbial world, perversely fail to fully honor God's command to go forth and multiply - rarely and very slowly reproducing.

Thus they remain a tiny minority in any wild population, less than 1%.

But why do they, the 'persisters' survive at all ?

Because when penicillin hits, it kills all the normal bacteria happily reproducing and only these few persisters survive to live another day.

When the penicillin treatment is over, they begin to reproduce - slowly - again and the disease reemerges.

The classic example is SBE, subacute bacterial endocarditis, the hitherto invariably fatal heart disease that Dawson gave his life to cure.

As the word 'sub acute' suggests, this disease is hardly a raging killer, but kill it did, in 100% of all cases, by being slow but steady - by being persistent, thanks to persisters.

The few persisters hiding out in the biofilm attached to our vital and delicate heart valves always remerged to give the disease another bite at the apple - and another and another.

Only a long hard course of penicillin finally got all the persisters - because like them, the dying Dawson was equally a persister.

Now on a more personal note, some of my in-laws have too much iron in their blood and need to have it removed periodically to survive a healthy long life.

'Defectives'.

Yes, 'out there' in Nature, they would indeed die sooner than others - though they had already successfully reproduced two children before the disease was detected, a hint that many defectives from all species do survive long enough to do so.

Other in-laws have too much iron in their blood, but not enough to need treatment to survive a full life.

Tendencies to have retain too much iron from our diet only hurt us when we have too much (iron-bearing) food but when we have too little food and little of that meagre amount has much iron, it helps ensure survival.

Another example, again personal, I have another 'defective' relative, one prone to get genetic-related childhood leukemia.

Now our extensive social safety net in fact does not 'simply keep her alive, sucking off the public tit'.

The disease until recently was fatal, net or not.

But some scientists and doctors, like Henry Dawson a half century earlier, denied the nihilistic conclusions that all defectives should be simply left to die, as out in Nature, and worked hard to find a cure instead.

Now she will grow up, work and pay taxes, maybe even find a cure for some other hitherto fatal disease.

'Defectives' broaden, deepen, strengthen the ultimate human social safety net : the human gene pool.

Pro-Brexit voters should have known that helping political firemen to put out the UK's economic fires was never going to start by their referendum decision to 'drain' the UK gene pool, by clamping down hard on letting in any strange new immigrants.

Because weird immigrants, like weird defectives, bring us the totally new ways that we sometimes need to survive a totally new crisis .....