A stable and widely accepted biological classification system is a precondition for biological sciences. Such a system offers the means to describe and converse about life without ambiguity. Traditional biological nomenclature and classification used the species as the basis of classifying organisms. As such, it was inadequate to categorize and name the vast genetic diversity within species. However, a recently developed biochemical technology had led to discoveries that have significantly improved the biological classification system. The DNA technology has enabled scientists to unearth enormous information on genetic relationships of organisms as well as their evolutionary ancestry in a manner that the use of structure could not reveal.
Before the invention of DNA technology such as DNA sequencing and DNA-DNA hybridization, scientists used species behavior and structure as the basic means of classifying organisms. However, with the discovery of genetic connections, scientists can more accurately demonstrate the relationships between different organisms (Baltrus, 2016). In particular, this has been helpful with prokaryotes, following that structurally, they are comparatively simple, unicellular organisms. For this reason, looking at the structure of prokaryotes offered a limited amount of information about their relationships, their evolutionary lineage, and classification of the diverse kinds of prokaryotes.
Information on DNA can not only reveal relatedness between different organisms but also indicate how long the organisms have been evolving separately. Biologists are increasingly grouping organisms into classes that represent lines of their evolutionary descent rather than relying only on physical similarities. As Crowson (2017) notes, the higher the taxon level, the more ancient the common ancestor of the organisms in the taxon. However, organisms that seem extremely similar may not have a common ancestor (Baltrus, 2016). The reason is that the genes of several organisms depict fundamental similarities at the molecular level. In light of this discovery, scientists can use similarities in DNA to determine the evolutionary relationships since DNA evidence expresses evolutionary relationships of various species. The more the comparability of the DNA of different species, the more recently they have a mutual lineage.
Moreover, different species that depict comparable DNA are more closely related evolutionarily. On the contrary, the more divergent different species are from one another, the less comparable their DNA (Baltrus, 2016). Therefore, evaluations of DNA are useful in marking the evolutionary time. Furthermore, a molecular clock estimates the period for which different species have been developing independently through the use of DNA comparisons, by relying on mutations to mark time. According to Panofsky & Bliss (2017), simple mutations in the structure of DNA occur often, with neutral mutations accumulating in different species at nearly the same rate. Therefore, by comparing DNA sequences in various species, scientists are able to tell how dissimilar the genes are and when the species shared a common ancestor. The future of evolutionary classification is hence more optimistic since technological advances in molecular biology is improving, thus will continue to translate into a developing and revisable classification system.
Overall, the advent of DNA technology in evolutionary classification, particularly DNA sequencing, has significantly transformed biology by bringing concomitant changes to the traditional Linnean system of classification. The traditional biological nomenclature and classification failed to provide means to name and classify groups of organisms described by the same level of similarity but do not depict comparable genetic diversity. Thus, the system was not effectively predictive of genetic relatedness. The invention of DNA sequencing has therefore revealed a level of genetic diversity, which the traditional biological system of classification could not adequately classify and name.
References
Baltrus, D. A. (2016). Divorcing strain classification from species names. Trends in microbiology, 24(6), 431-439.
Crowson, R. A. (2017). Classification and biology. Routledge.
Panofsky, A., & Bliss, C. (2017). Ambiguity and scientific authority: population classification in genomic science. American Sociological Review, 82(1), 59-87.
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