Nantucket has one of the largest deer populations in the state, estimated to be more than 3,000 animals. But it wasn't always this way. A century ago, the island was devoid of deer.
The origin story of how deer came to Nantucket is something of a local legend. According to the Nantucket Historical Association, it began on June 3, 1922 "when fishermen rescued an exhausted buck swimming in Nantucket Sound. They brought him to the island and released him. Three and a half years later—on February 23, 1926—summer resident Breckinridge Long purchased two does from Michigan and had them liberated in the vicinity of Squam Swamp to keep the solitary buck company. "
Proliferation ensued, and today it is assumed that the island's deer herd is largely inbred, and can be traced back to those original does brought in from Michigan. But is that accurate?
According to a new study on the origins of Nantucket's deer population by researchers from Framingham State University, the Linda Loring Nature Foundation on Nantucket, and Eastern Connecticut State University, that assumption is indeed correct. Their research - which included mitochondrial DNA analysis of deer fecal samples and muscle tissue - supports the hypothesis that only a handful of deer are responsible for the huge population that now inhabits Nantucket.
The article based upon this research is set to be published in the journal Northeastern Naturalist later this year but has already been posted online. The paper shows what the researchers called the "founder effect": reduced genetic diversity as a result of a population descended from a small number of colonizing ancestors.
The study was led by Dr. Rick Beckwitt, of Framingham State University, along with Dr. Sarah Bois, of the Linda Loring Nature Foundation, and Bryan Connolly, of Eastern Connecticut State University.
"Combining history, wildlife ecology, and genetics to tell the story of our Nantucket deer is interesting enough," Bois said. "Supporting undergraduate students in research and learning new skills in a real-world situation is a big motivator for this type of work."
According to the research team, mitochondrial DNA sequences are inherited from mother to daughter in the female lineage without combination with the paternal genetics. "Therefore, for the old Nantucket story to be true, the deer population should only have two major mitochondrial types all inherited from the two original female deer imported from Michigan," the researchers stated.
The study sampled deer from Nantucket, mainland New England, and Michigan. The island deer resulted in three distinct genetic sequences - two of which were the most common, and those were identical or nearly identical to the sequences from the Michigan deer.
"Results indicate that most deer on Nantucket did originate from two founding females from Michigan, and a small percentage are descended from later introductions from mainland New England," the researchers stated.
Beckwitt posed the question about Nantucket deer to his students at Framingham State who were enrolled in the "research experience in biology" class to help them learn how to use genetic techniques to investigate real questions.
"Combining history and Nantucket lore with scientific research has shown that there is truth in the local lore," they said.