Evolution does not respect a separation of concerns

In programming, one of the most important things an architect aspires to is “separation of concerns”. But there is no such thing in living organisms. Evolution mashes things together in complex ways and then relies on death to perform the validity checking that programmers would normally do with unit tests.

But even the most incompetently written theme isn’t as poorly designed as vasopressin, which, among other things, controls:

Water permeability of distal tubule and collecting duct cells in the kidney.
Increasing permeability of the inner medullary portion of the collecting duct to urea by regulating the cell surface expression of urea transporters.
Memory formation.
Peripheral vasoconstriction as a response to blood loss from serious injury.
Pair bonding.
The same hormone that controls your blood pressure also determines if you can form a relationship.

From “Arginine vasopressin receptor 1A”:

Homozygosity in allele 334 of RS3 is associated in men (but not women) with problems with pair-bonding behavior, measured by traits such as partner bonding, perceived marital problems, marital status, as well as spousal perception of marital quality.[19]

In a study of 203 male and female university students, participants with short (308-325 bp) vs. long (327-342) versions of RS3 were less generous, as measured by lower scores on both money allocations in the dictator game, as well as by self-report with the Bardi-Schwartz Universalism and Benevolence Value-expressive Behavior Scales; although the precise functional significance of longer AVPR1A RS3 repeats is not known, they are associated with higher AVPR1A postmortem hippocampal mRNA levels.[5]
Who the fuck designed this? The answer is, of course, “nobody”. The blind idiot god of evolution cares not at all for separation of concerns, or design elegance, it just cares about how many offspring are produced. For evolution, the person who died at the age of 29, with six children, and the person who lived for two hundred years and won six dozen Nobel prizes, but never had children, it considers the latter person to have failed.

It’s even a mistake to think of evolution as an “entity” with “intent” or “purpose”: evolution is the simple historical fact that the genes of the organisms which produce more offspring are more frequent in the general population. And so we have white blood cells that trigger diabetes when they don’t have parasites to combat, or the thousand and one autoimmune diseases of an environment that is too clean: the blind flailing of an immune system fighting a battle that’s already won.