I had with me a sci-fi tome, “Seven Eves” by Neal Stephenson, and a glossy real estate magazine. Because our house is at the lower end of the price range, I like to ogle the spreads of zillion-dollar estates.
So I opened the magazine to “Historic Waterfront Chilmark Home,” with a current image of a spectacular house on the left, and a view from 1901 on the right, behind owners Benjamin and Hattie Mayhew. The house was built in 1878 on 6 acres overlooking two big ponds. A mere $5 million pricetag.
Benjamin Mayhew was a descendant of Thomas Mayhew Sr, who “bought” the island in 1641, although the Wampanoag tribe of Gay Head and their ancestors had lived there for more than 10,000 years. Benjamin and his brother Jared were deaf, as were both of their parents, an uncle and two aunts, and many others. I’d forgotten the wonderful story of the deaf community of Martha’s Vineyard, so thought I’d share it here.
A Classic Founder Effect
The tale of the island deaf is compelling not only because it so beautifully illustrates a genetic founder effect, but it is also an unusual blurring of disabled versus abled. The story has been told well in many places, including Arthur R. Railton’s excellent “The History of Martha’s Vineyard“, Nora Groce’s “Everyone Here Spoke Sign Language: Hereditary Deafness on Martha’s Vineyard“, and a 3-part series by audiologist Bob Traynor.
The deafness on the Vineyard traces its roots to Weald, in the County of Kent in England. The pilgrims brought the recessive allele here an unknown number of times.
The first deaf person known to live on Martha’s Vineyard was Jonathan Lambert, born in 1657 into a prominent family on Cape Cod. He had one deaf sibling and five siblings who could hear. Jonathan married Elizabeth Eddy, who was from the island, and they moved there in 1692. Two years later he bought what is today Lambert’s Cove from a Wampanoag. A diary entry from April 5, 1714, from a Judge Sewall wrote of Jonathan Lambert that he “spake not a word to us, and it seems he is deaf and dumb.” Other accounts call him a “deaf mute.”
Jonathan and Elizabeth had 7 children. The two born deaf, the first cases known to have been born on the island, didn’t have children, but the condition appeared again because the others were obligate carriers – each had to have a recessive allele because their father had 2 copies of the mutation.
The numbers of deaf grew as the few and large founding families intermarried, and a unique local sign language evolved. At one point the town of Chilmark actually required residents to know and use it. The deaf people held the same types of jobs as everyone else, even serving in public office, and town meetings and other get-togethers used sign language.
The outside world was not so understanding. A newspaper account from the 1860s reported “an almost incredible number of deaf and dumb persons” and that “these calamities can only be accounted for … by the intermarriage of relatives.”
Census reports from the 1800s show a climbing number of “total deaf and dumb.” In the 1800s one in 155 people on the island was born deaf, and in the large connected families of Chilmark and especially in the communities-within-communities such as Squibnocket, near the house that is currently for sale, the figure was 1 in 25. At one point a newspaper reporter claimed that it was 1 in 4, but he was relying on the remarks of a carriage driver who might have been referring just to one large family. Still, that figure was reported in the real estate listing I saw last week. In the general population about 1 in 6,000 people has the form of hereditary deafness on Martha’s Vineyard.
Alexander Graham Bell is part of Martha’s Vineyard deafness lore. In 1884 he sent his private secretary, Frank Z. Maguire, to visit the deaf-mutes of the island. The inventor of the telephone was interested because his father had studied the physical basis of speech, in Scotland, and Alexander taught speech to deaf people in Boston. 1884 fell between the publication of Gregor Mendel’s famous paper that would have described how deafness seemed to pop up now and then in families with hearing parents, but before the “rediscovery” of said paper.
With Mendel’s first law still unknown, scared people looked for environmental explanations. There was relief at the realization that the Indians could hear – therefore deafness wasn’t catching or due to exposure to the clay cliffs of the area. But Bell got the genetic connection. He drew detailed pedigrees of the families with hereditary deafness and deduced that it traced back two centuries to shared ancestors.
Prejudice outside the accepting community of Chilmark continued. A doctor, S. Millington Miller, wrote in 1895 in an article called “The Ascent of Man” that some of the deaf were also blind and “some are idiots.” He interpreted Bell’s findings to mean that the deaf on Martha’s Vineyard were seeding a new human species, and some sources credit Bell with this idea directly. Bell’s wife was deaf and he reportedly argued vehemently against sign language and urged the deaf to instead learn to speak so that they could fit in.
The deafness of the founding families of Martha’s Vineyard is due to mutation in a connexin gene called GJB2. Connexins are small proteins that loop in and out of cell membranes at four points. Six connexins join, and pairs of the six form “gap junctions” between cells. In the inner ear, the connexins maintain the high potassium ion concentration in the fluid that is necessary to convert a vibration into the neural signal that stimulates the auditory cortex.
The GJB2 mutations are the most common cause of autosomal recessive deafness in the world, accounting for about half of all cases. And about half of the 3 in every 1,000 individuals born deaf has a genetic form. Hereditary deafness came to account for a greater proportion of cases after antibiotics became available to treat ear infections.
I mentioned at the start my immersion in a fantastic book called SevenEves. It’s an end-of-the-world plot, not exactly a new idea, but the mechanism is indeed unique, and the book adheres to Isaac Asimov’s rule of “change one thing”.
So last week, there I was on Planet of the Apes beach, reminded of the deafness on Martha’s Vineyard resulting from a founder effect, and reading a novel about an engineered, orchestrated founder effect that saves humanity. And I’ve been thinking about it ever since.
If we could restart our species, which gene variants, and the traits and talents that they confer, should we choose?