The islands have a population of 301. The main settlement is Edinburgh of the Seven Seas (known locally as "The Settlement"). The only religion is Christianity, with denominations of Anglican and Roman Catholic. The current population is thought to have descended from 15 ancestors, eight males and seven females, who arrived on the island at various times between 1816 and 1908. The male founders originated from Scotland, England, The Netherlands, the United States and Italy, belonging to 3 Y-haplogroups: I (M170), R-SRY10831.2 and R (M207) (xSRY10831.2) and share just eight surnames: Glass, Green, Hagan, Lavarello, Patterson, Repetto, Rogers, and Swain.[n 1] There are 80 families on the island. Tristan da Cunha's isolation has led to an unusual, patois-like dialect of English described by the writer Simon Winchester as "a sonorous amalgam of Home Counties lockjaw and nineteenth century idiom, Afrikaans slang and Italian." Bill Bryson documents some examples of the island's dialect in his book, The Mother Tongue.
From how many ancestors is the current population of 15 thought to have descended from?