I. Beyond The Blue Horizon
Out in the far-western Pacific lies a young nation of widely-scattered islands and coral atolls called the Federated States of Micronesia. It covers an area of ocean as large as the United States, but its total land area is no bigger than Rhode Island. Among the hundreds of flat, ring-shaped atolls are Pingelap and Mokil (Mwoakilloa). Either island group would easily fit into the area of the Brandeis campus, yet both are separated by hundreds of miles of water from their nearest neighbors.
These islands have been of interest to geneticists because of the occurrence of a distinct form of total colorblindness, or achromatopsia, among their small populations. It is carried in the genes of three out of ten Pingelapese, and causes actual colorblindness in four to ten percent of the islands people. On Mokil, about one percent are affected.
II. The Strand That Binds Us
Well-known and studied within the scientific community, the affliction was first brought to public attention in 1996 with the publication of The Island of the Colourblind by the celebrated neurologist Oliver Sacks.
People with achromatopsia cannot perceive color at all, only shades of grey, and have low visual acuity. The affected individuals also experience photophobia, a heightened sensitivity to light, requiring them to squint continuously while outdoors.
Descriptions of the condition were published by researchers in 1970, and many investigative teams have visited the island in the intervening decades. Though its symptoms were exactly like occurrences already known in other parts of the world, the Pingelapese variety was found in 1999 to be from a mutation on the eighth chromosome, a different segment of the human DNA strand.
III. The Founders Legacy
The spread of achromatopsia on Pingelap Atoll began with Typhoon Lengieki, which devastated the island around 1775, reducing the population from 500 to approximately 20. In a phenomenon called the founder effect, the population reduction gave a selective advantage to the survivors genes. The Nahnmwarki (High Chief) Mwahuele is believed to have been the founder, or original possessor of the colorblindness gene after the storm. He bore three children who traveled to Mokil in the 19th Century and introduced the disease there as well. On Pingelap, widespread occurrences of achromatopsia first became evident in the 1820s in the fourth generation following the typhoon.
There is no effective treatment for achromatopsia, though some simple measures can mitigate the effects of some of the symptoms. Dark glasses can keep people from having to squint in daylight, and magnifying glasses or monoculars can assist people in seeing small or distant objects. On isolated Pingelap and Mokil, however, such products are unavailable.
IV. What Man Is An Island
Though originally shunned, achromatopes gradually gained social status, since, in this small, subsistence-based society, cooperative work and the pooling of resources are vital for survival. One reason they were able to win acceptance lies in the local custom of nighttime fishing, an activity obviously requiring good vision in darkness. Thus it became a specialty of the Pingelapese achromatopes with their heightened light sensitivity. It is a great irony that the colorblind, able to work more efficiently by night, in effect render those with normal vision the disabled ones after the sun sets.
There is little doubt that rapid advances in genomic mapping will enable investigators to better understand and eventually to treat conditions such as achromatopsia. The question of greatest importance, however, lies not in the investigation of colorblindness as a disease, but rather in how one small society has chosen to deal with the condition, accommodating and valuing its affected members without stigmatizing or marginalizing them.
V. For Giving Us Vision
In a little-known corner of the far Pacific, a tiny community has endured the trials of subsistence life, extreme isolation, colonial domination, and catastrophic weather. By a wholly unique circumstance of genetics, these modest people have also endured a continuing health impairment, a shared destiny that has transcended the generations.
In recent years, the modern world has paid regular visits to their shores in pursuit of knowledge. Indeed, we have gained a wealth of understanding that will benefit those with achromatopsia and other genetic conditions;
yet, in the culture of the Pingelapese we have found not merely knowledge, but also a source of wisdom that is to the benefit of all who would heed it. For that we are in debt to the people of Pingelap Atoll.
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