A Peppered Past

MOTHS AND MOTHERS

Like Margaret Drabble who recently published an assessment of the matrilineal genes and memes that she inherited from the family of her mother, Kathleen Marie Bloor, I have come to feel an affinity with a moth.

Ms Drabble has titled her semi-fictional exploration of family history and the cascading intergenerational quirks of its female members, ‘The Peppered Moth’ – presumably because a moth is a moth and a Bloor is a Bloor, even though both may seek to change their spots to fit in.

The novel deals with difficult relationships - between parents and offspring, and between family and a sense of place. Away from the grime and gloom of South Yorkshire, the youngest in the line of ‘Cudworth’ women, Chrissie (Margaret’s self representation), comes to life in a perverse, wicked, rebellious streak, drawn to "lust, adultery and alcohol".

But fighting off the family curse of depression which has darkened the lives of her womenfolk, the fourth generation narrator finds it difficult to avoid a harsh, dismissive, censorious tone in assessing her forbears. In fact, she finds it hard to avoid sounding like her mother. And left to settle in Sheffield once more, no doubt the darkness would come to predominate in adjusting to nature.

So moths and mothers make an interesting counterpoint.

Let’s start by talking about the moths. The Peppered Moth (Biston betularia) is a dowdy, night-flying moth that used to haunt woodland trees in a greyish-white that blended well with lichen-covered bark.

When the early 19th century collectors first identified it, it was a predominantly light-winged with black speckles. But in 1848, a black variant was identified in Manchester that blended in much more effectively with the increasingly soot-stained trees of industrial Northern England.

By 1895, 95% of the Lancashire peppered moths were black – and this dark form then spread across Britain until the lighter form began a resurgence following the 1956 Clean Air Act.

The shift in hues in response to camouflaging and predation was seen by evolutionists as a clear vindication of the theory of natural selection, though disputes arose on the validity of the science and creationists seized the opportunity to argue that, as their had always been lighter and darker forms, proportionality was the only issue.

But Mike Majerus, Professor of Evolution at Cambridge University recently spent seven years repeating the earlier studies on the predation of the peppered moth. He compiled enough visual sightings of birds eating peppered moths to show that, in rural Cambridgeshire, the black form was significantly more likely to be eaten than the peppered now that air pollution had declined.

“The peppered moth story is easy to understand,” he explained, “because it involves things that we are familiar with: vision and predation and birds and moths and pollution and camouflage and lunch and death. That is why the anti-evolution lobby attacks the peppered moth story. They are frightened that too many people will be able to understand.”

Adding: “If the rise and fall of the peppered moth is one of the most visually impacting and easily understood examples of Darwinian evolution in action, it should be taught. After all, it provides the proof of evolution.”

And more recent research by Ilik Saccheri, an evolutionary biologist at the University of Liverpool, UK, and his colleagues has shown that show one mutation from a single ancestor causes increased dark pigment, called melanism, in the typically light-coloured moth.

Saccheri's team used a genetic technique called linkage mapping to search for the gene responsible. A linkage map puts traits in groups according to how often they are passed on to the next generation together, which indicates how close together they sit on a chromosome. The closer the traits are in the genetic sequence, the less likely it is that they will be separated during sex-cell division, and the more likely it is that they will be passed on together.

To make the map, Saccheri and his colleagues twice crossed a dark male moth with a light-coloured female; the result was 132 offspring with varying traits. The traits most often inherited alongside dark coloration were matched up with genes of the silkworm (Bombyx mori) — a closely related moth species with a sequenced genome.

The locations of the genes for the traits pointed to a narrow region on chromosome 17, where the scientists say that a single gene variant is probably responsible for the peppered moth's melanism, although they don't yet know exactly which one it is.

Once the chromosome region was identified, the researchers examined moth samples collected all over Britain between 1925 and 2009. The same group of gene variants huddled in the chromosome region closest to the mutation in the dark moths, providing strong evidence that natural selection had acted recently on an advantageous mutation from one individual. If a mutation had been in the population for a longer time, or had come from multiple individuals, the selection of traits that were inherited together would vary more widely.

"It's not just the one mutation that has been swept through the population, it's that whole chunk of chromosome that has hitch-hiked," says Saccheri.

"It's a big breakthrough as far as peppered moths' industrial melanism is concerned," says Laurence Cook, a retired population geneticist from the University of Manchester, UK. He has been studying the peppered moth since the 1960s. "We've been going on for an awfully long time knowing just the classical Mendelian genetics."

DISAPPEARANCE OF THE SHORROCKS

Like Margaret Drabble, I have Northern English ancestors and a somewhat quarrelsome relationship with my family’s matriarchy. As my mother used to say ‘You can’t kill squitch’ (i.e. invasive couch grass). As if anyone would dare try?

But in my case it is the male-line ydna rather than the female-line mitochondrial dna that is of most interest from a genetic and behavioural point of view. I never knew my father as he was killed in the RAF in 1943 before I was born and, as my mother pretty much turned her back on his family, I grew up knowing very little about the ‘Johnsons’.

But as with the Peppered Moth, genetic techniques have uncovered a story about evolution – the evolution of my Johnsons from the Shorrocks family of Salford. In a similar effort to avoid being conspicuous – my grandfather changed his name when he left the North around 1905 (though oral history confirms that he could not divest himself of his cloth cap and pipe). Regardless, he could not change the genetic signature that he passed on to succeeding generations.

So we can match the darkening of the moth over the 19th century with the history of my family – though in our case, the change of hue and spots was much more abrupt.

As recounted by Derek Antrobus, pre-industrial Salford was ‘a pretty town with orchards, market gardens and homes of quite prosperous people arranged around a street called Greengate where the market square was to be found’. In 1773, its population was less than 5,000 – but this modest, historic town was already growing and my paternal ancestors who moved there from Blackburn were among the early immigrants.

In 1764 William ‘Sharrock’ married Sarah Rix at Prestwich, and a 1797 Trade Directory record William as a Calico-glazier, living Wood Street, Salford. William and Sarah had two sons, Richard (b 1788) and James (b 1793).

By 1801 the population of Salford had reached 29,495 and it was over 40,000 when James married Elizabeth Butterworth in 1815 (as James Shorrocks). The marriage certificate records James as a Brushmanufacturer, and Pigot’s 1821 Trade Directory shows that James and his brother Richard were joint owners of a workshop at 22 New Bailey Street, Salford.

By this time, Salford had become one of the first sparks off the anvil of the Industrial Revolution. Following the opening of the Bridgewater Canal in 1761, which halved the price of coal, and the development of the steam engine and textile machinery, urban growth caught fire, engulfing the old town. As described by a contemporary of James:

‘Houses have now displaced the verdure in all directions, and the pellucid character of the river has been destroyed by chemical refuse, and although the old localities still retain their favourite names – names suggestive of ‘Flora and the countrie green’ – they form so odd an amalgamation with the new streets to which they are wedded that the contrast raises our mirth along with our melancholy.

Wheat Hill has not an ear of corn to bless itself withal; Springfield has lost every trace of the vernal season; Garden Lane, Posy Street, Blossom Street and the Old Orchard lead to anything rather than fruit and flowers. Even Paradise [Vale] and Paradise Hill are shorn of their primeval attractions; and as to the Green Gate that once guarded Salford’s pastures – where shall we look for that?’

Later, by the time my great, great grandfather Walter Shorrocks was recorded as a 15 year old in the 1841 Census, the population of Salford had reached 91,361. And when my great grandfather Robert Edwin Shorrocks was recorded as a 7 year old in the 1861 Census, the population was 148,740 – with Walter living with his wife Ann (nee Collinge) and their three sons at 21 Islington Street, Salford, employing 2 workmen in the brush manufacturing workshop attached to the dwelling.

As contemporary photographs and the comments of Friedrich Engels make it all too clear, by the mid-1800s, the pleasant town known to William and James had become overcrowded and squalid in many areas. New rail connections in 1841 and 1881 and the opening of Salford Quays on the Manchester Ship Canal in 1894 accentuated the process.

By the time my grandfather Harry Shorrocks was recorded a 2 year old in the 1881 Census, (living with his father Robert who managed the brush stocks as a warehouseman and mother Fanny Eliza [nee Mallinson]) the population of Salford had reached 228,822.

It was over 300,000 in the Dirty Old Town when, as a young man Harry turned his back on Salford forever, settling in South London under his new alias Harry ‘Johnson’.

MOTHS AND FATHERS

There are many young people who run away and start afresh. But going further and changing one’s surname is an act that has repercussions beyond the immediate and personal. It affects all those who come later.

It raises possible limitations to our rights of reinvention.

Coming to the end of his life, Harry must have mused that no harm had been done. His three sons had produced what looked like a final total of four grand-daughters and it would have looked as though the Shorrocks name and ancestry were safely moribund. Then I popped up as a posthumous child, just a year before he died in June 1945.

But as the grandson who was cut free from his family history, I take exception to the fact that my father and his brothers and I were forced to fly, so to speak, under false colours.

Then there are the many, many hours of family history research that I spent dredging through the Johnsons in the Censuses looking for brush manufacturers. And the subsequent loss of my adopted brush manufacturing Johnson family of West Ham – and the embarrassing illegitimacy of my relationship with some of their lovely descendants the Bosleys.

So what drove Harry to turn his back on all that he knew and seek anonymity in London? We’ll never know – but we do know that he died as overweight and probably alcohol dependent. And that he had a reputation within my mother’s family as someone who became animated and inappropriate at any Bit of a Do, trying too hard to impress the ladies.

Or another way of putting it is that, like Chrissie the Margaret Drabble self-insert, he had a ‘wicked, rebellious streak, and was drawn to lust, adultery and alcohol’. Come to think of it, that covers some episodes in my own life.

So an independent streak to the caterpillar can be seen later as selfishness and self-indulgence in the post-pupated moth.

Getting back to my mother, on bad days she saw my grandfather rather than my father born again in me – particularly if I was going through a stouter or more exuberant spell. ‘You are just like your grandfather Johnson’ was sure to bring me to heel.

But like so many of the participants in the ‘Who Do You Think You Are’ series, I have found a sense of resolution and affinity in re-establishing my more distant family links. Looking back, something always seemed to be calling me from the past.

And what of my younger boys – are they, like the Peppered Moth, in the process of returning to ancestral type?

This is a hard question. As with any empirical work in the social sciences, it is difficult to avoid the observer intruding on the experiment.

In fact my own role in the story is now centre stage. Looking back over the last 200 years or so from the marriage of James and Elizabeth Shorrocks in 1815 to the present, you have a neat division between a Shorrocks century and a Johnson century – and I have been around for a third of the overall total.

I would like to think that my boys have inherited Shorrocks virtues and avoided Shorrocks vices but the likelihood is that they will see their lives much more in terms of the present day – focussing on reinvention in the light of the genes that I exhibit and the memes that I have spun.

But the family home is now called ‘Shorrocks Hey’ and my younger boys and I sometimes sing a little song going to school in the car based on a Bob Marley classic - ‘I shot the Shorrocks - but I did not shoot the deputy’. And Sam my eight year old has expressed dissatisfaction at being given his mother’s surname and flagged some interest in renaming himself Sam Shorrocks when he gets older.

As for the thirty and twenty-eight year old sons, they have, for the time being, rejected their father’s mutation into a Kiwi and dissolved back into the life of London - perfectly camouflaged.