Earlier this week the Nobel Prize for medicine or physiology went to Barry Marshall and J. Robin Warren for the discovery that the bacterium Helicobacter pylori can cause ulcers. Their hypothesis was not well received at first, but they continued to build support for it--including by Marshall fulfilling Koch's Postulates on himself by swallowing the bacteria, giving himself gastritis, and then curing himself with antibiotics.
About half of the world's population is infected with the bacteria; only a small percentage move on to develop gastritis, ulcers, or cancer. Carl Zimmer explains that H. pylori is a useful tool for investigating human migrations. Changes in the genome (micro-evolution, if you will) ought to correspond with the movement of humans.
Continue Reading
The Molecular Ecology article that Zimmer links to is a review article about this kind of investigation. Not all microbes are well-suited for this kind of study, but in addtion to H. pylori another microbe that is useful is Human Papillomavirus (HPV), particularly the sexually transmitted ones. HPV types 16 and 18 are notorious for their involvement in cervical cancer. Researchers have looked at these HPVs around the world and found that they cluster into groups that are consistent with the current view of human migration. (Origin in Africa, movement to Europe and Asia, and from Asia into the Americas.)
This paragraph in the article caught my eye:A closer look at isolates from Native Americans also revealed unexpected results. Although an association between isolates from Greenland Eskimos and lineage E [Euoropean] was not surprising due to the proximity between Greenland and Europe, the same link was observed in many isolates from Navajo, Pueblo and Amazon Indians! These latter ethnic groups originated from North Asiatic emigrants via the Bering Strait and should therefore be associated with the AA [Asian/American] lineage. Even more surprising was the isolation of the Af1 [African 1] lineage from one Inuit and the Af2 [African 2] lineage from two Navajos. However, despite these discrepancies and possible [lateral gene transfer], the population structure of HPV-18 viruses does largely mirror human migrations reliably and shows reasonable congruence between independent genes within and between subtypes, unlike many other viruses.
Now there are probably ten very good explanations for why the African lineages have shown up in Native Americans. But of course, given our belief in the Book of Mormon, any hints of pre-Columbian contact with the Old World are of special interest.
Overall, the human and microbial genetics support an Asian origin of Native Americans. It would be irresponsible to draw any conclusions about these HPV anomalies--especially any about support for the Book of Mormon. I only bring it up as a matter of interest.
Having said that, I would pay money to hear someone get up in church and say, "There is evidence that the Nephites brought a sexually transmitted disease to America."
(The original research paper is available here.)
Continue reading...