Biomedical Ephemera, or: A Frog for Your Boils

Anencephaly in the skeleton and whole fetus

Anencephaly is the congenital absence of the skull and neocortex, due to a neural tube defect between the 23rd and 26th day of pregnancy. At that point, the embryo is basically a tube with a thickened top, and when that top end doesn't close properly, the part of the brain known as the telencephalon (the largest part of the brain, which includes the cerebral hemispheres and basically everything that allows us to experience the world and live life) doesn't form, and because that doesn't form, the skull above it isn't triggered to form, either.

Anencephalic fetuses still develop some of the lower facial bones, the mandible, and the rest of their body, but the neural network of the spinal cord terminates at the brain-stem, and the condition is necessarily terminal, if the fetus even makes it to term. This is one of the few conditions that is often allowed to undergo late-term (generally second trimester) abortion - as these fetuses generally die in utero, and late-term fetal death is often very problematic in terms of infection and partial delivery, it's much safer to induce labor and expel the fetus before this occurs.

Studies in mice have shown that folic acid supplementation (already common in females of child-bearing age) can drastically reduce one of the primary causes of anencephaly in humans (expression of the CART1 gene). However, as the condition is so rare in humans, and the supplementation of folic acid is already highly recommended to prevent other neural tube defects in fetuses (such as spina bifida), no studies with the same hypothesis have been, or will probably ever be, performed on humans.

Human Monstrosities, Part II. Barton Cooke Hearst and George A. Piersol, 1892.

Mus muscalis var. nudo plicatus. - "Rhinocerous mouse"

The rhinocerous mouse is a common mouse with a variant on the same gene that's known to cause "standard" hairless mutation (without all the wrinkles). This variant has given us a lot of insight into various aspects of the skin, as the wrinkled and hairless skin is highly susceptible to skin conditions, and they have little-to-no strong bonding between the subdermal tissues and the dermis.

Modern lab mice aside, these guys are really cool on their own - especially since they were discovered in 1854! Despite the mutation causing significant health defects (such as long nails, cysts, and glandular problems, especially with the thymus), the average life-span of rhinoceros mice is still long enough to produce several litters of offspring, each bearing the same genes and of the same mutated phenotype. The naturalist John S. Gaskoin secured several individuals of this appearance, which were living wild behind the paper mills of Maidenhead Bridge, England. When the female gave birth to a litter of pups all resembling her mutation, he remarked that unlike solitary mutations seen previously (such as albino crows, born from and producing black crows), this collection of individuals was remarkable in that it clearly demonstrated the adage "like begets like".

Bear in mind, this was before Gregor Mendel's works on heritability were "re-discovered" in the 1880s. The theories of genetics, inheritance, and parental influence on offspring appearance, especially in mutation cases, were not understood, and the adage of "like begets like" was not necessarily thought to have anything to do with the unchangeable characteristics of the parents.

John S. Gaskoin went on in a later paper to propose that "like begets like" only applied to what something was like at infancy - since these mice were all born wrinkly and nude, they gave birth to wrinkly and nude. While still far from what we know today, it was certainly a big step forward from the common assumptions of the day - for example, if a man was buffed-up and muscular when he impregnated a woman, the offspring would automatically be more muscular because of that.

But these wild-living wrinkly nudist mice, which were so obviously Mus musculus, yet so obviously completely different from normal common mice, were one of the first solid bricks in our wall of genetic knowledge, over half a century before we even started getting a grasp on the mechanics of DNA, and what makes our offspring look the way they do.

Proceedings of the Zoological Society of London. John S. Gaskoin, 1854.