Guinea Pigs At The Chalkboard

Pica working on her comic about the guinea pig Mr. Ginger reminded me of a story about the great twentieth-century geneticist and evolutionary biologist, Sewall Wright. This is recounted in Jim Endersby’s book A Guinea Pig’s History of Biology which covers a lot more than just guinea pigs: rather it is a history of biology told from the point of view of the subject organisms (there are chapters on fruit flies, corn, and many other species in addition to guinea pigs).

A couple of interesting facts about guinea pigs before I get to the Sewall Wright story.

• When guinea pigs were imported from the New World the English took quite a fancy to them. Queen Elizabeth I even had one as a pet.
• They were important study animals in the discovery of vitamin C and its role in the prevention of scurvy. Like humans but unlike rats and mice, guinea pigs do not synthesize their own vitamin C, so they are good subjects for this topic.
• The eminent twentieth-century British biologist JBS Haldane studied guinea pigs for a while because his sister took up keeping guinea pigs after she developed an allergy to horses. (They were an upper-class family.) Their lawn didn’t have croquet hoops or tennis nets, rather there were about 300 guinea pigs running loose behind the fencing. The genetics experiments came to a tragic end in the penultimate generation when a friend’s fox terrier jumped the front gate and frightened all the guinea pigs to death. (Incidentally, Haldane was a British communist who like many of his compatriots including George Orwell went over to Spain to fight the Fascists).

Together with JBS Haldane and R.A. Fisher, Sewall Wright (1889-1988) was one of the three key figures in developing the mathematical theory of evolution in the first half of the twentieth century. I first heard of him in my undergrad courses around 1982 and 1983 on population genetics and evolutionary biology. Wright was still alive at that point. I more recently ran across him while reading Judea Pearl and Dana Mackenzie’s popularization of the theory of causal inference, The Book of Why. Wright in 1921 developed the mathematical technique of path analysis, which is an important precursor to causal inference theory.

Wright fell into working with guinea pigs because he was offered a position as a graduate student to be a caretaker of a research colony of the animals, and he kept working with them for most of his career. The following story about Wright is apocryphal, and according to his biographer William Provine the story isn’t true, but is fun to relate nonetheless. As background, although Wright was incredibly conscientious and generous with his time, he was not a very good lecturer. This is quoted from an interview with a student of Wright’s, the paleontologist Robert Sloan:

I didn’t see this, but my friend and partner, Ernie Lundelius, who was one of the groomsmen in my wedding, describes a case where Wright brought in a guinea pig. He was displaying the guinea pig and showing some of the variations in coat color. This particular guinea pig was somewhat more fractious than usual and was scurrying around on the desk and was not about to be quiet. When Wright worked at the blackboard, traditionally he tucked an eraser in his left armpit. And to keep the guinea pig quiet, he tucked the guinea pig in his left armpit. And when he was through and ready to erase some space so that he could put the next equation down, he reached for the eraser and grabbed the guinea pig and started to erase the blackboard with a squeaking guinea pig. Of course, this was one of the tales that went around among all the students of evolution. Whether they had been there or not, I doubt it ever got into print. It deserves to be there, as part of at least the bibliography of Sewall Wright.