If you spend some time in Times Square you will perhaps be reassured that humans are a genetically diverse species. After all, we come in various sizes, faces, bodies, hair, skin and, eye colors, and personality traits. But are we really a genetically diverse species compared to others?
Genetic diversity is defined as genetic variability present within species. Genetic diversity is the product of the recombination of genetic material in the process of inheritance. To make that possible in humans, there is randomness in the genetic information combinations of eggs and sperms. This results in unique human DNA, even among siblings.
In maintaining the genetic diversity of humans besides sexual reproduction, mutation of genes, genetic drift, and gene flow are also important.
Is Being Genetically Diverse Important?
Genetic diversity increases genetic variation, which is a key factor of natural selection. The genetic variation of a human population is important for its robustness. This is to say, with the spread of a deadly virus, or the drastic environmental change genetic variation increases the likeliness of enough people’s survival to repopulate.
The main sources of genetic diversity are the formation of new traits, the change of gene number or position, rapid reproduction, and sexual reproduction. All other factors stable, over time genetic diversity of populations, including humans” increases.
Human genetic diversity
Our population is closing in on to the 8 billion marks, we are scattered all around the world, yet, surprisingly we are the least genetically diverse primates. Our closest cousins alive, the chimpanzees, inhabit rather close to each other, their population is less than 55,000 yet their genetic diversity is remarkably more than ours.
99.9% of human DNA is about being Homo Sapiens, which is our species. It is the variations in the rest of 0.1% (not 1%) of our DNA makes each of us unique.
If an alien landed on Earth and heard that we were categorizing, and even discriminating, ourselves based on the tone of skin color, and facial characteristics, it is a safe bet that, the alien would fail to understand why.
Our limited genetic diversity
Although, now extinct, other human species migrated earlier from Africa to Europe, Homo Sapiens’ migration didn’t happen before less than 70,000 years ago.
On the other hand, keep in mind homo sapiens is about 100.000 – 250.000 years old as a species. In other words, if an average baby of her time was somehow brought from 100,000 years ago to our time, she would grow up to become one of us.
If we bring these facts together it becomes clear that we were already who we are as a species when we first stepped on Euroasia. Recognizable cosmetic differences among some populations are the result of partially or totally isolated human populations for long periods of time around the world.