Race and Variation
Introduction
Race and variation in human beings are structured by geography with respect to traditional patterns of genetic drift and gene flow. Genetic variation is, as a result, distributed in an overlapping and continuous manner of clustering populations into races determined by their geographic ancestry is imperfect. The definition of Race is nevertheless dynamic since it is based on both criteria and context, which gives rise to the notion of Race and variation. The contentious issue of Race is partly driven by the assertions of contemporary scientists like Charles Darwin and Alfred Russel Wallace. The two scientists developed the natural selection model, which posited that human variation can be explained through evolution and adaptation (38). Consequent scientific studies led to advances in DNA technology, which have justified that these variations exist instead as a result of mutation and gene flow. Although human beings tend to have robust hereditary viability that is responsible for persistent distinct physical features, in reality, every individual’s uniqueness is tied to the human genome. This means that genetic variation is more prevalent within a specific population rather than between isolated racial groups. Genes seamlessly explain a lot of variations in sample populations and also about the ancestry of human species instead of an individual. Evolution is, therefore, continuous since the genomes of future generations are uniquely developed to have inimitable and more robust features than the parental generation (Understanding Race). Additionally, human populations have never been fully isolated using genetic boundaries since the human species has a common origin and thus shared genetic markers (34). Modern human genetics will thus go a long way in presenting scientific support demystifying the definition of Race as non-overlapping and discrete units. Accordingly, Race may cease to be an inflammatory issue religiously, scientifically, and socially since genetics can explain the extraordinary variations.
Meiosis
Complex organisms have a unique sexual reproduction, which produces gametes through a process of cell division called Meiosis. Compared to mitosis, Meiosis undergoes two phases of cell division that are characterized by the reduction of chromosomes. Meiosis occurs in both male and female specialized reproductive cells to form mutated gametes (sperm and egg), which merge to develop a fetus during the reproductive process. Meiosis occurs in two phases, with the first division leading to two daughter cells that finally split into four (68). In the first stage, homologous chromosomes through a procedure called recombination pair and swap DNA information. These pairs shift strategically to the middle of the cell, with each carrying additional DNA information. Subsequently, the chromosome pairs end up splitting by moving to opposite ends of the cell, which later pulls apart into two daughter cells. Each with one chromosome copy from the homologous pairs thus partial the number of chromosomes at 23. Meiosis II begins with the non-partner chromosomes lining up at the center of the cell. They split their chromatids at the centromere, and two non-matching strands drift to opposite ends of the cell. The final division occurs, resulting to four cells, each holding 23 chromatids or single strand chromosomes. Meiosis is crucial in variation since its random nature, and genetic recombination leads to the creation of gamete cells with unique genetic combinations. Different combinations of parental genotypes can be created through Meiosis, which creates an extensive and diverse variation range (70). Furthermore, Meiosis avoids abnormal cell compositions with more chromosomes during conception that would threaten the existence of all sexual reproduction organisms.
Mutation and Gene Flow
Genetic mutation refers to the process through which the DNA sequence is altered permanently in the genes of persons. Humans are believed to have originated in Africa. Still, due to migration all over the world’s continents, mutation caused by the dynamic environmental conditions leads to racial categorization, a form of both genotypic and phenotypic variations. Mutation leads to genetic variation since it can trigger changes in phenotypical or mendellian characteristics of an individual. Genetic variation as a result of mutation, therefore, occurs in either the reproductive or somatic cells. It is, however, important to note that mutations on somatic cells, although responsible for variation, do not in any manner contribute to evolution since they cannot be passed on to future generations (95). This shows that although a mutation may not be heritable genetically, it leads to changes in the dynamics of a population by establishing fresh phenotypic and genotypic variances.
Gene flow accordingly contributes to genetic variation through the introduction of new alleles by first-time entrants in a community. Gene flow essentially leads to alteration of allele frequencies by incorporation of different gene pools in a population sample, which creates novel combinations of genes through interbreeding (96). This also leads to genetic variation since the products of gene flow differ significantly from both the phenotypical or mendellian features of their parents.
Genetic flow and mutations are terms that were discovered long after Alfred Russel Wallace and Charles Darwin had already cemented their natural selection hypothesis. However, it is evident that both Darwin and Wallace were not aware of the scientific data validating natural selection. Their theory is able to give a simple rationalization of the possible processes involved in evolution, emphasizing that only the favorable qualities can be passed on to the future generations (38). This indirectly suggests that genetic variation is solely controlled by the existence of variations in a population; otherwise, this population would run out of existence. In contrast, mutation and gene flow explain genetic variation as a flawless process where hereditary traits are passed on through modification of alleles in individuals. This is because both favorable and unfavorable dominant alleles can be passed on to other generations. More to this, natural selection posses that sexual mate selection is done based on favorable traits; gene flow and mutation, on the other hand, are determined by sexual reproductive cells through Meiosis. This shows that natural selection can be controlled while mutation and gene flow happen arbitrarily, confirming that Darwin and Wallace were not aware of these two concepts.
Scientific research during the era of Wallace and Darwin was not driven by racism. Instead, both scientists whose careers were influenced by Thomas Malthus decided to take on a different approach to their mentor. While Malthus was keen on studying humans only, Wallace and Darwin-based their theories on all species (32). By concentrating on all species it shows that scientific research was based on understanding the variations visible among various species and participation of the environment in evolution. Nonetheless, these theories challenged long-held traditional religious assumptions supporting fixity of species. The religious system wielded immense power, and both Wallace and Darwin were respected members of society, which explains why their studies shied from digressing to humans. Darwin was extremely cautious about publishing his findings, and focusing his research on humans would have drawn further condemnation (37). This, therefore, proves that Darwin and Wallace’s studies were not motivated by racism but rather a deeper understanding of evolution in all species.
Facts about Race and Variation
- There is no exceptional definition of Race since there exist subsets of similar variations between races.
- Race can be defined based on the unchanging traits that are continuously preserved through heredity during the evolution of the specific population, making them distinct from each other.
- Primary races are the cluster of traditional race classifications; African, Asian, European. Secondary races evolve from interbreeding of primary races and thus share mutual racial markers.
- Charles Darwin did not embrace the race school of thought and instead traced human origin to a common ancestry sharing a single gene pool.
The facts above illustrate how variations in human DNA are determined concurrently by the environment and genetic composition. Different continents have varying environmental stressors, and their adaptation is geared towards existing in that setting (Understanding Race). This would explain why each Race is identified based on the continent each subset majorly occupies. It also illustrates why populations are unlikely to evolve and lose the distinctiveness since each appearance is designed to adapt to a specific environment. However, due to gene flow, interbreeding leads to a different subset of individuals exhibiting mixed features who should also be collectively defined as a unique subset of Race. As was already illustrated above, Darwin based his research on a single ancestry for all organisms and, as such, gave neither attention nor logical explanation for the existence of Race in the human species.
Works Cited
Jurmain, Robert., Kilgore, Lynn., Trevathan, Wenda., Ciochon, Russell. Introduction to Physical Anthropology. Wadsworth, Cengage Learning, 2014.
Understanding Race, www.understandingrace.org/RaceAndHumanVariation.