The story of humanity’s origin, from the African apes that walked upright five million years ago to the modern Homo Sapien, was taught to us as a linear transition with this familiar graphic.
This is not how evolution works. Life is not on a road trip from ape genetics to human genetics. The genome responsible for our development expands in every possible direction that it can with each generation. Picture evolution as an explosion in three-dimensional space, rather than a line from one point five million years ago to another point in the present day.
With every generation of children, the genome experiments with what experiments and differences it can get away with, through the advantageous process of deviation. If a baby comes to full term, this experiment in deviation was a success. If that baby grows to become a full adult, able to create a new generation, and has children themselves, then the deviation was very successful, and most often the differences will be passed on to future generations as an inherited trait.
These experiments in deviation are an important part in the resilience of the species. If we all followed the same genetic pattern, copied and pasted from one person to another, one environmental catastrophe, such as a virus, that killed one person could potentially wipe out all humans. Long ago, the genomes that played with variation outlasted the genomes that did not dare deviate.
As deviation shaped the bodies of the modern Homo Sapien from our ape ancestors, so too did deviation shape our brains. Instead of a linear path of brain development, from Hominoidea (ape) to Homo Sapien, the genome explored new possibilities for the brain with each generation for millions of years. Few of these experiments in variation were successful, but the experiments that worked became the thousands, then millions, then billions of brain blueprints found throughout the human race today.
As each of us has a different body, due to this generational variety, each of us has a different brain. Each person has a different way of behaving, communicating, and perceiving the world around them. If we were in a state of nature.
Our understanding of autism in 2020 is that it is in 4 out of 5 cases a set of inherited traits, passed down from parent to child. Autism is not a disease, disorder, or genetic mistake; it is in most cases passed through the genome, the blood of our ancestors, just like our height, body shape, and skin colour. Not only that, given that 1 in 59 people in the world are autistic, we can say that autism is a most desirable trait in a partner. We can also speculate that since autism is a global phenomenon found in nations all over the world, all autistics can trace their heritage to a single ancestor; a single instance of variation, happening long ago before humans migrated out of our cradle in Africa 50,000 years ago.
Research on autistic genes in 2003 argues against the idea of a single autistic ancestor. When scientists attempted to locate the elusive “autistic gene”, for the purposes of searching for a cure for our diversity, they found that over one hundred genes were responsible for autism. These one hundred genes could not be tampered with, because the genes responsible for autism were also responsible for everything from the healthy maintenance of our internal organs to the thickness of our fingernails.
So perhaps without one gene to call the origin of autism, it is possible that we are not descended from a primal autistic ancestor that all autistics can trace their geneology to. Perhaps, instead of a family, we are a tribe.