Evolutionary genetics: yes, we come from monkeys

Evolution and the origin of life

The origin of life on Earth dates back 3.5 billion years, when the first living organisms appeared: bacteria. After this initial event, life gradually diversified, achieving a great biodiversity of species, with broad genetic population variability, on our planet. But how did all the species that have inhabited or currently inhabit the Earth originate? Evolutionary forces of change are the cause of the appearance of new species and the great biodiversity that our planet currently has.

The theory that supports biological evolution and is approved and agreed upon by the scientific community is Darwinian theory. Alfred Wallace and Charles Darwin They defended natural selection as the main source of change and the evolutionary process. In addition, this theory maintains that species change over time (some become extinct and others remain), that evolution is a continuous process, that organisms that are phenotypically and genetically similar are related and come from the same ancestor, and finally, that the change in species is due to the Natural selection . That is, within each generation, there is variability in certain characteristics, and only those that present an adaptive advantage for survival in a specific environment are inherited by subsequent generations.

Misrepresentation of evolution:

How does this variability between organisms occur? For this variability, which causes the phenomenon of speciation, to appear, it is necessary that the change brought about by the evolutionary process be genetic level , meaning that this change occurs in the DNA. These changes are driven by the organisms' need to adapt to the environment they live in. Therefore, changes at the genetic level can be triggered by alterations in the environment in which they live or by movements that living beings make to a different environment.

Synthetic theory

The synthetic theory advocates the study of evolution from a genetic perspective, to understand how these changes occur in the process of speciation. The main evolutionary forces that drive this change and genetic variability are:

• Mutation : Changes in the DNA sequence that may or may not be noticeable. Most mutations de novo that appear in an organism and are not a consequence of inheritance.
• Migration : This phenomenon occurs when a population moves to a new habitat, resulting in changes in genetic frequencies caused by sexual interbreeding between different populations.
• Genetic drift : This occurs when the population size is small and the probability of transmitting certain alleles to offspring increases. This results in decreased genetic variability among organisms (loss of heterozygosity).
• Natural selection : is the evolutionary force that allows those individuals who possess a favorable genetic variant to increase their survival in the environment in which they find themselves, to have greater biological efficiency, that is, they are more likely to reproduce and transmit that characteristic to their offspring.

The scientific discipline that studies all these aspects is Evolutionary genetics , which is responsible for analyzing the distribution of alleles transmitted from generation to generation. One of the most relevant laws in this discipline is the Hardy-Weinberg Law, which holds that, under conditions of random mating, population allele frequencies remain constant from one generation to the next in the absence of disturbances such as evolutionary forces. In this way, the population would be in equilibrium. However, this theoretical situation is not what occurs in reality, since these evolutionary forces of change must be taken into account, which do act in the natural world, altering allele frequencies and, therefore, the genotype of each individual.

Human evolutionary genetics

In recent years, the genetics This has allowed for a more exhaustive analysis of the degree of kinship between different species, thus achieving greater precision when classifying them. Therefore, thanks to new genome sequencing technologies, we can verify the degree of similarity of human DNA with other species such as the rat (more than 80% similarity), the chicken (more than 60% similarity) and the Chimpanzees , with whom we share 99% of our genes. That is, only 1% of the genome differentiates us from this species. This last fact has led many geneticists to discuss including chimpanzees in the same genus as humans, a topic that has been and continues to be highly controversial in the scientific community.

In short, the evolutionary genetics It allows us to understand the degree of kinship between different species, as is the case between humans and other species. Therefore, this discipline is important for understanding how our bodies function and the causes of the heritability of certain traits that may have no apparent function at present, but which can be explained by tracing the evolution of species.

In fact, despite genetic studies, the genes involved in the development of some human characteristics, such as cranial capacity and brain development, language, and bipedalism—qualities that differentiate humans from chimpanzees—are still poorly understood.