The Island of the Colorblind

Darwin cited short-term evidence of this subsidence – palm trees and buildings, for instance, formerly on dry land, which were now under water; but he realized that conclusive proof for so slow a geologic process would be far from easy to obtain. Indeed, his theory (though accepted by many) was not confirmed until a century later, when an immense borehole was drilled through the coral of Eniwetak atoll, finally hitting volcanic rock 4,500 feet below the surface.[13] The reef-constructing corals, for Darwin, were

…wonderful memorials of the subterranean oscillations of level…each atoll a monument over an island now lost. We may thus, like unto a geologist who had lived his ten thousand years and kept a record of the passing changes, gain some insight into the great system by which the surface of this globe has been broken up, and land and water interchanged.

Looking at Pingelap, thinking of the lofty volcano it once was, sinking infinitesimally slowly for tens of millions of years, I felt an almost tangible sense of the vastness of time, and that our expedition to the South Seas was not only a journey in space, but a journey in time as well.

The sudden wind which had almost blown us off the landing strip was dying down now, although the tops of the palms were still whipping to and fro, and we could still hear the thunder of the surf, pounding the reef in huge rolling breakers. The typhoons which are notorious in this part of the Pacific can be especially devastating to a coral atoll like Pingelap (which is nowhere more than ten feet above sea level) – for the entire island can be inundated, submerged by the huge wind-lashed seas. Typhoon Lengkieki, which swept over Pingelap around 1775, killed ninety percent of the island’s population outright, and most of the survivors went on to die a lingering death from starvation – for all the vegetation, even the coconut palms and breadfruit and banana trees, was destroyed, leaving nothing to sustain the islanders but fish.[14]

At the time of the typhoon, Pingelap had a population of nearly a thousand, and had been settled for eight hundred years. It is not known where the original settlers came from, but they brought with them an elaborate hierarchical system ruled by hereditary kings or nahnmwarkis, an oral culture and mythology, and a language which had already differentiated so much by this time that it was hardly intelligible to the ‘mainlanders’ on Pohnpei.[15] This thriving culture was reduced, within a few weeks of the typhoon, to twenty or so survivors, including the nahnmwarki and other members of the royal household.

The Pingelapese are extremely fertile, and within a few decades the population was reapproaching a hundred. But with this heroic breeding – and, of necessity, inbreeding – new problems arose, genetic traits previously rare began to spread, so that in the fourth generation after the typhoon a ‘new’ disease showed itself. The first children with the Pingelap eye disease were born in the 1820s, and within a few generations their numbers had increased to more than five percent of the population, roughly what it remains today.

The mutation for achromatopsia may have arisen among the Carolinians centuries before; but this was a recessive gene, and as long as there was a large enough population the chances of two carriers marrying, and of the condition becoming manifest in their children, were very small. All this altered with the typhoon, and genealogical studies indicate that it was the surviving nahnmwarki himself who was the ultimate progenitor of every subsequent carrier.

Infants with the eye disease appeared normal at birth, but when two or three months old would start to squint or blink, to screw up their eyes or turn their heads away in the face of bright light; and when they were toddlers it became apparent that they could not see fine detail or small objects at a distance. By the time they reached four or five, it was clear they could not distinguish colors. The term maskun (‘not-see’) was coined to describe this strange condition, which occurred with equal frequency in both male and female children, children otherwise normal, bright, and active in all ways.

Today, over two hundred years after the typhoon, a third of the population are carriers of the gene for maskun, and out of some seven hundred islanders, fifty-seven are achromats. Elsewhere in the world, the incidence of achromatopsia is less than one in 30,000 – here on Pingelap it is one in 12.