BALTIMORE—Geneticists at the Johns Hopkins University announced Monday that an estimated seven million people worldwide carry a distinctive genetic marker linking them to a single smooth-talking common ancestor.

Gwilym of Many Conquests is believed to have smelled amazing for a ninth-century Welshman.

According to the study, which analyzed blood samples from 4,000 participants in 17 countries, the lineage appears to have originated with a highly virile ninth-century Welsh nobleman known as Gwilym of Many Conquests.

"This is one of the largest diasporas known to have descended from a single progenitor," said head researcher Lawrence Ghilcrest, adding that DNA evidence now corroborates stories about the Welshman that historians once dismissed as myth. "To have propagated his genetic material so effectively, and across so much territory, we can only infer Gwilym was quite the charmer."

"As the poets often wrote, he got 'more arse than a chamber pot,'" Ghilcrest added.

According to lore, Gwilym was a persuasive mead-house balladeer known for his "gilded, tunic-dropping verse." Many texts note his total lack of standards concerning the age, weight, and appearance of the women he bedded, claiming that his silk-adorned pallet never lay cold for even a single night after his 17th birthday.

The Johns Hopkins study attempts to trace the flow of Gwilym's genes from the British Isles through Europe, North Africa, South America, Asia, and back to South America. Because his DNA spread so quickly, researchers put credence in stories about Gwilym and his immediate offspring traveling great distances on the mere rumor of a loose handmaiden.

Though little is known of Gwilym's life, artists have traditionally depicted the suave nobleman riding an eye-catching white mustang and wearing garishly colored linen garments that fall loosely about the chest to reveal a large medallion bearing his family's crest. It is remarkable, historians note, that he was able to spread his seed so far and wide before the age of 29, when he was savagely beaten to death by a neighboring lord known as Dafydd of Nine Cuckolds.

"Records indicate Gwilym was often accompanied by a retinue of male hangers-on, to whom he would occasionally bequeath a female he had already had his way with," said Lucas Pearson, a prominent medievalist at Cardiff University. "A surviving account from one of these men, Emrys the Drought-Plagued—who described himself as 'saddled by cruel fate with damnable bouts of celibacy'—bitterly derides Gwilym's callous, indifferent treatment of his conquests after his seductions were complete."

"You really can't blame people for being envious of Gwilym, though," Pearson continued. "I mean, how did this jerk do it? Unbelievable."

According to Johns Hopkins' Ghilcrest, the genetic marker his team discovered primarily manifests itself in the trait of extreme persistence, often making its carriers completely impervious to rejection.

"It's rare to see one dominant trait express itself so uniformly in a genealogy across time," said Ghilcrest, noting that this very trait appears to explain why Gwilym had such success in passing down his DNA. "Like his modern descendants, [Gwilym] would systematically approach every woman in his immediate vicinity and engage in elaborate courtship rituals that sometimes lasted 10 or 12 hours. When every opportunity for coupling was exhausted, he would move on, often covering a great deal of ground in a single evening."

Emmanuel Chereskin, a biologist at the University of Rochester, said the genetic marker also produces some unique secondary phenotypes among those who carry it. These include long, flowing hair; superior whistling skills; and especially muscular arms and shoulders that may facilitate long bouts of casually leaning against walls. Gwilym's descendants have also been shown to produce a strong and intoxicating natural musk.

"These individuals are extremely adept at feigning interest in even the most tedious topics," said Chereskin, referring to an experiment in which men who carry the marker were asked to listen to an attractive woman talk at length about plans for her sister's upcoming wedding. "Additionally, when properly cued, they will reflexively spin subtle innuendo from even the most banal phraseology."

Chereskin added that theories of genetic expression suggest several well-known public figures are likely descendants of Gwilym, including actor Matthew McConaughey and Vice President Joe Biden.

News of these findings have prompted many to undergo testing to determine if they too might be descended from this celebrated medieval Lothario. Reginald Sperino, a 36-year-old Henderson, NV waterbed salesman who tested positive for the sequence, said he is proud to come from such a noble line of sweet-talkers.

"I always thought there was something special about me," Sperino said. "I mean, what can I—hey, there, beautiful—what can I say? It's nice to finally have an explanation for my je ne sais quoi."