Opposites Attract

I'm sure everybody has heard the saying 'opposites attract' in reference to a multitude of different things, whether that be magnetic charges, animal interactions, etc. Well, research over the last decade or so has come up with actual evidence for this being the case, not only in non-human relationships, but also in human relationships. The basis for this claim rests in the quest for organisms to have stronger, more diverse DNA, which for the most part, results from more exposure to varying nucleotide sequences. There is a complex found in animals (as well as, humans) called the major histocompatibility complex (MHC), which participates in cell recognition, as a major component of the immune system. It is also well known that there are harmful, deleterious effects that occur from mating between family members. This of course has a high probability of hampering offspring development. Due to these deleterious effects resulting from interbreeding, there is actually evidence from studies that people and other animals instinctively (built in from evolution) seek out mates (more so on the female's part because it deals with when they are in a fertile state). What is the way they do this you ask? Through pheromones. Without getting too into the specific details, the DNA and subsequent proteins, code and function in producing representations of the MHC and other DNA components in the form of pheromones that the males and females secrete. The secretions are sensed so that the females and possibly males (in some other form) can seek out a mate, all in an effort to diversify their DNA for evolutionary stability purposes.

FOOD FOR THOUGHT: Other pheromones that females secrete out of the arm pits, are responsible for the alignment of menstruation cycles with women living in a house together for a extended period of time. The pheromones are sensed by glands in the nasal cavity, which send these signals to the brain via an efferent nerve. The brain then determines when the menstruation occurs. Another evolutionary stable move, because animals that have young at the same time, with other animals they are close to, can help raise the offspring, thus reducing the fitness cost (ex: lionesses carrying for cubs that are not theirs).