He Polygeneticism Is a theory that d It is evident that the human species is divided into races whose origin is due to different lineages. It has been developed to explain the origin and evolution of man.
According to polygenism, the hominids living in Africa emerged in a first and, years later, the evolved men left in a second wave of Africa and met the inhabitants of those lands.
It is a theory that quarrels with the notion of original sin advocated by the Catholic Church. It has also been said that it is a conception of man that served to justify slavery.
Protagonists of polygenism
Ernst Haeckel, who profusely spread his interpretation of the ideas of Darwin Among the German-speakers, was a supporter of polygenism arguing that the human being was a genus divided into nine species separated from the appearance of speech.
While Carleton Coon, defender of a modern polygenism, each human race evolved separately (multiregional hypothesis).
In any case, it is a belief that has not been consolidated enough to generate consensus among the scientific community.
Polygenism and human biology
The first theories that spread about the origin of the modern human being, proposed that the races referred to different biological species with little or no genetic flow between them.
For example, the multiregional model, based on the fossil record, suggests that a parallel evolution of Homo erectus to Homo Sapiens occurred after the migration of Homo erectus from Africa (more than 800,000 years ago).
According to the model of recent African origin (RAO), all non-African populations share an ancestor: Homo sapiens, which evolved in Africa about 200,000 years ago, and replaced populations found outside Africa (the Neanderthals, for example).
In fact, investigations into phenotype, mitochondrial DNA (mtDNA) and Y chromosome reveal that migration originated from eastern Africa.
Since humans, as a species, share an ancestor and are genetically similar, what scientific basis does the notion of races hold? The answer seems to lie in the field of demography.
It happens that man does not mate at random; The possibilities of mating are greater among beings living in the same geographic region and sharing the language.
This is so both by the natural process of genetic drift and by the tendency of humans to mate with those with whom they share certain phenotypic characteristics.
There are population structure studies that investigate genetic variance among populations and are based on Sewall Wright FST.
This is a statistic whose results range from zero (without differentiation) to one (without shared genetic variation).
When the results reflect a low FST value it could mean that there are recent common ancestors or high levels of migration.
Many studies reveal higher levels of genetic variation in African populations than in non-African populations; Populations outside Africa only have a fraction of the genetic diversity within it.
It is necessary to consider that there are demographic factors that affect the genome: the size and structure of the population, the founding effect and the addition.
The non-random association of alleles is termed linkage disequilibrium (LD), and science has found that Africans have LD lower than Eurasians and Americans.
This may explain why the ancestral African populations maintained a larger effective population size (Ne) and consequently had more time for recombination and mutation to reduce their LD.
Beyond this and the variations imposed by the adaptation of individuals to their immediate environment (for example, immunity to certain diseases or variation of melanin that affects the color of the skin), the correlation between what is popularly Understood as"race,"and the actual physical variations in the human species, is virtually nil.
Polygenism and religion
Faced with the monogenism posed by Christian Genesis (origin of humanity in a single pair), polygenism proposes that human life was formed in several places in a relatively simultaneous way and that the name Adam does not refer to a single person but Refers to the collective"men"and / or"humanity".
This interpretation, heretical until the middle of the nineteenth century, has been considered as an attempt to explain scientifically, without renouncing the Christian faith, the few human generations between Adam and Eve and humans today.
This doubt raised by Voltaire in 1756 found some followers and resistant opposition in the Catholic Church not only to attack one of their main dogmas of faith but to find historical evidence of a biological and cultural evolution so fluid that it can not be Restricted to some stages joined by transitions.
Polygenism and human rights
Since polygenism also functioned as a scientific way of justifying slavery, human rights advocates have spared no effort to refute it.
In the mid-twentieth century, the international human rights movement focused on biological experiments focused on research on the racial types and hierarchies involved.
At that time, the discussions that were generated in the scientific community made us think of a dissolution of the hierarchy between the races, even though the existence of the same was still assumed.
In fact, today molecular biology and genetics continue to try to find evidence of the existence of races.
It is that the notion of races continues in force and rooted as a social category in the West, perhaps because of the habit, for many reductionist, to think of categories.
While from medicine it is said that this type of classification allows to develop public policies of health more suitable, for other sciences contributes with the efforts to know the evolutionary history of our species, but for a human rights activist generates stigmatization for certain populations .
References
- Britannica (s / f). Race and the reality of human physical variation. Retrieved from: britannica.com.
- Herce, Rubén (2014). Monogenismo y poligenismo in Scripta Theologica / VOL. 46 / 2014. Retrieved from: unav.edu.
- Lipko, Paula & Di Pasquo, Federico (2008). How biology assumes the existence of races in the twentieth century. Scientiae Studia, 6 (2), 219-234. Retrieved from: dx.doi.org.
- Martinez Martinez, Stefa (s / f). Polycentric theory of Paul Rivet. Retrieved from: en.scribd.com.
- Tishkoff, Sarah (2004). Implications of biogeography of human populations for 'race' and medicine. Retrieved from: nature.com.
- Trevijano, Pedro (2016). Original Sin Vs. Polygenism. Retrieved from: religionenlibertad.com.
- Wade, Peter and others (s / f). Retrieved from: britannica.com.
- Wolpoff, Milford and Caspari, Rachel (s / f). Race and Human Evolution. Retrieved from: books.google.co.ve.