IN the attic, amidst children’s toys and teetering towers of books, is a box containing the history of my family. What it holds doesn’t just stretch back 100 or 200 years, but to the dawn of human life, showing the composition of my entire ancestry. There’s a tiny bit of Africa, a microscopic dash from the Far East, and a big dollop of Europe, south, east and especially north. That’s about it. No names, no specifics, just broad brushstrokes that speak less to any individual distinctiveness than to the waves of migration from which almost everyone in these isles has emerged.

For such a momentous record, it’s disappointingly slim: a handful of maps, graphs and pie charts, conjured out of a test-tube of spit and much scientific polish. I wish I could say I found it fascinating, but to be honest, I’d much rather know more about my mother’s Bavarian grandfather, who made violins and travelled the world in an orchestra, or my father’s grandmother, an unmarried Irish maid obliged to flee to Scotland because she became pregnant (by her employer).

Compared to such eventful lives, my test-tube analysis delivered a vague and unsatisfying ancestral footprint. Researchers from the University of Edinburgh working with the Royal College of Surgeons in Ireland, however, have conducted a far more illuminating DNA analysis across both countries. In so doing, they have discovered what some of us have long suspected: that for centuries, many Scots have barely budged an inch from where their forebears were born.

According to Professor Jim Wilson, from the Department of Human Genetics at Edinburgh University, “It’s remarkable how long the shadows of Scotland’s Dark Age kingdoms are, given the massive increase in movement from the industrial revolution to the modern era.” Needless to say he is not talking about Glasgow, which has been like Central Station in terms of arrivals and departures. It is a different story, however, in the north-east, the Lothians and Borders, the south-west, and Shetland and Orkney. Here, today’s populations show astonishing levels of indigenous intermarrying, of living, breeding and dying in the same locality as their parents and siblings.

For this very reason, Aberdeenshire is an ideal microcosm for medical case studies. Thanks to its unusually homogenous inhabitants, whose genetic roots go back centuries, it has been possible to chart the development of certain diseases, among them dementia, and explore their origins, and possible cures. In Orkney and the Shetlands, meanwhile, the higher than average incidence of those with multiple sclerosis strongly suggests a regional predisposition, in this case among natives whose Norwegian inheritance can make it feel like a Scandinavian outpost. If a day out of Hawick is a day wasted, a day in Lerwick is in some respects akin to a visit to Bergen.

Now, while areas of the Lothians or the north-east have been washed by incomers since Vikings and Frenchmen sailed into the firths, not to mention oil drillers in our own times, these findings do not come entirely as a surprise. In the space of a mere 250 miles between Alford in Aberdeenshire and Wigtown in Dumfries & Galloway, for instance, it’s possible to note regional differences that go deeper than accent or traditions.

I am more fanciful than most, but I cannot be alone in noticing the strongly distinctive personality you find in former coal-mining communities in the Lothians, in hill-farms of the Borders, or in coastal villages on the dazzling blue Solway coast. Their individuality is one of the things that makes these areas attractive. While much of the world is growing blander with every passing year, as we mimic how others eat, speak and shop, in the heart of Galloway, the Orkneys or the Borders, you cannot fail to notice that you are in an utterly individual place. It is not as if time has stopped here, more that time is understood. Locals know something of the area’s history, and instinctively recognise where they fit into it.

In many ways, the abundance of long-standing ties in genetically close-knit areas is a boon. It helps build strong, resilient communities, with access to a support network that city dwellers can only dream of. But, naturally, there are downsides. I’ll never forget the Saturday evening when a gay friend and I, renting a cottage in leafy Gifford, walked into the local pub. The babble of voices stopped dead. As we made our way to the bar the only sound was the sigh of the door as it closed behind us, and a creak as all heads turned in our direction. This was Deliverance, a reminder that even in bijou East Lothian, primitive values still held sway. Strangers were a source of suspicion, deemed guilty until proven innocent.

It’s easy to mock the insularity of postcodes where the majority still share the same surnames as in the Doomsday Book. One of the reasons their villages or towns have survived so long is that for centuries they have fiercely, perhaps even unthinkingly, protected themselves from the incursions of potentially threatening incomers. Strangers rarely brought good tidings, but it was the worst kind of news when they settled and married, thereby dividing loyalties and diluting old family lines. In the process they might bring God knows what strains of disease or infirmity into their midst.

Ironically, of course, the biggest downside of a genetically contained community is the risk of inherited defects and ill-health, as the Hapsburg dynasty could attest. From schooldays we’re warned of the dangers of inbreeding, a word almost synonymous with ignorance. And certainly, as youngsters, some of us couldn’t wait to flee to pastures new. Yet for others, why wouldn’t they want to live somewhere they were happy, with family nearby?

Added to which, the areas covered in this latest DNA study are among the loveliest in Europe, a source of envy, not disdain. In previous ages, only the well-off could afford to travel, so parochialism was relative: a 30-mile journey was an adventure, the stuff from which cosmopolitans were made. Today, you could live to senility in the house where you were born, yet still keep wholly in touch with world affairs. Whether this is a persuasive argument for staying put probably depends on your personality – and that of the area where you live.