In comparison to many other species, humans exhibit relatively low genetic variation. On average, humans differ by approximately one in a thousand base pairs, amounting to an average pairwise variation of 0.1%. This level of genetic diversity is even lower than that found in chimpanzees. In fact, many plants and bacterial species exhibit higher genetic diversity than humans, although the term “species” may be applied more loosely in the case of bacteria. Human genetic diversity is also lower than that observed in the model plant organism Arabidopsis thaliana.

Additionally, humans typically possess the same number of chromosomes, unlike many other species where variation in chromosome number is prevalent. For instance, populations of garden dormice across Europe and Northern Africa exhibit chromosome numbers ranging from 46 to 54.

While there are several species with lower genetic diversity than humans, this can often be attributed to factors such as limited geographic range or human-induced reduction in population and genetic diversity. Cheetahs, for example, have critically low genetic diversity primarily due to human influence.

The reasons behind the relatively low genetic diversity in humans are not entirely clear. It is suggested that the small long-term effective population size rather than a severe bottleneck during human evolution contributes to this phenomenon.

It is important to note that discussions about human genetic diversity can become racially charged. However, it is crucial to understand that human diversity is primarily within populations rather than between them. Between-population diversity often follows a gradual gradient without well-defined boundaries. This challenges the notion of discrete “races” as commonly imagined and emphasizes the inaccurate conceptualization of human diversity. Humans do not possess subspecies.

In conclusion, humans exhibit lower genetic diversity compared to many other species. Genetic variation within human populations is more pronounced than variation between populations, which tends to display clinal patterns. Increasingly, the scientific community acknowledges that major genetic discontinuities do not exist between continents or “races.”