Bloody Isle

Saxons, Vikings, and Celts: The Genetic Roots of Britain and Ireland, By Bryan Sykes, 320 pp., W.W. Norton, $26.95

Until recently, the best attempts at genealogic inquiry have cleaved to myth and history, both rife with imprecision. In a postgenomic era, however, one would assume that genealogy has been transformed. Modern phylogenetics offers seductive possibilities, synthesizing molecular genetics, statistics, and computation. The discipline traffics in haplotypes, but for the purposes of popularization, traditional narrative elements inevitably creep in. So, books in this infant field often practice a bait and switch. Promising groundbreaking science authors eventually fall back on the tricks of the historian or mythologist to enliven the data.

In his most recent effort, Saxons, Vikings, and Celts: The Genetic Roots of Britain and Ireland, Oxford geneticist Bryan Sykes demonstrates the promise and ultimate limitation of this endeavor. In exploring the Y and mitochondrial haplotypes, Sykes focuses mainly on the dominance of "Oisín." Named for the son of an Irish folk hero, Oisín epitomizes the Celtic substratum, and his lineage is preponderant throughout the Isles. Dilution occurs only along King Arthur's fabled Saxon Shore. Oisín's ascendance hammers home the refrain that today's Britons are the indigenous descendents of the Ice Age settlers who swept north out of Iberia 10,000 years ago. Later waves of Saxons and Vikings left only light genetic footprints. Thus the book's British title, Blood of the Isles: Exploring the Genetic Roots of Our Tribal History, serves its message better but might have been a tougher sell in a multicultural America.

Sykes supplements this textured narrative with appendices that transpose the haplotype frequencies onto maps - scientific genealogy shorn of verbal adornment and beautiful in its simplicity. But a story falls flat without dramatic tension, which Sykes delivers, while glossing over weaknesses in his scientific case. Male and female phylogenies are the heart of the book, but these two branches in the vast tangle of our genetic ancestry do not tell the same tale. Female lineages suggest that nearly all Britons are descended from the first post-Ice Age settlers, but the male lineages tell us that a substantial minority of Saxons and Vikings came to British shores. While daughters might be sent to the next village to live with their new husbands, younger sons would venture over the horizon to seek their fortunes.

Such distinct histories left their signatures upon these two lineages, but one wonders what other tales lurk in the genome. The nonrecombinant nature of mitochondrial and Y chromosomal sequences makes them particularly suitable for reconstruction of genealogical trees, but labs that sample other genes have reached alternative conclusions about the extent of human migrations and ancestral contributions to modern populations. Finding out who's right may need to wait until entire genomes from diverse populations can be sampled, sequenced, and analyzed. When at last all the genes can stand and be counted, we may finally put mythology to rest.

Newamul Khan (a.k.a. Razib) blogs regularly at www.gnxp.com and www.scienceblogs.com/gnxp, and he is a Run Unz Foundation Junior Fellow.