I’m glad you enjoyed this article. I too find the sheer depth and breadth of Darwin’s illness(es) to be quite fascinating!

It’s true that one of the alternative hypotheses for Darwin’s illness could be Chagas Disease; the thinking is that he contracted it whilst aboard the Beagle. However, there are many conflicting reports on this matter: Darwin did not report any of the typical initial symptoms, for example, and it is actually more difficult to get infected as it is not the insect bite which infects someone, but their excrement.

There is a fascinating article in this month’s ‘American Scientist’ on the recent theories surrounding Darwin’s illness (including Chagas Disease), and I suggest you take a look if you haven’t already – you might find it interesting!

Thanks,
Anne

There are indeed genetic markers associated with lactose intolerance! One such gene is called the LCT gene. Normally, the LCT gene, which encodes lactase, is turned on only for the first few years of a mammal’s life. After this, the enzyme level decreases and with it the ability to digest large quantities of milk. But some people produce lactase throughout their life and can drink milk without uncomfortable side effects. In different populations across the globe, the local prevalence of the lactase persistent phenotype varies widely—between 0 and 100%. A genetic marker (or SNP) near the LCT gene controls whether the lactase enzyme is turned on or off as a person grows older.

Fortunately, 23andMe customers can see whether or not their are likely to be lactose intolerant, as lactose intolerance is one of over 90 traits listed in our Health and Traits section.

Thanks for reading!
AnneH

Are there any genetic markers for lactose intolerance?

Interestingly enough, that very issue was brought up a few years ago by physicians who were researching Darwin’s suspected lactose intolerance. As it turns out, sea voyages of the 19th century rarely had dairy products on board (due to the difficulties of preservation), so his dairy consumption would have decreased during the 5 year voyage. As a result, his symptoms would (theoretically) diminish as well.

I also find it interesting that one of the fathers of modern biology and his physicians were unable to correctly diagnose him at the time! Just goes to show how the field of genetics has helped us to understand these disorders (and many more!).

Thanks for reading!

Anne

Interestingly enough, there ARE ways to discover the genetics – to some extent – of deceased individuals without having to exhume their bodies! By obtaining DNA from several of Darwin’s direct descendants (great-grandchildren, etc.) we could examine their Health and Traits information to see their risk levels for both lactose intolerance and Crohn’s. However, due to the inheritance patterns for Crohn’s Disease (and, to a lesser extent, lactose intolerance) we may not find any conclusive evidence on Charles Darwin’s condition. But what an interesting research prospect for sure!

Thanks for reading!

Anne

I can’t help finding it mildly ironic that one of the keenest observational minds in the history of science failed to take note of a family history of similar symptoms and draw the obvious conclusions – or maybe he did!

Lucky for us that, despite not being the fittest, he survived.

Thanks,
Jeff