How Modern Science Has Backed Up Previous Experiments on Atoms

This week’s paper ‘From Atoms to Traits’ describes modern science’s explanations for historically significant experiments. Specifically focusing on passages from Darwin’s origin of species, Mendel’s pea experiments, and comments on Watson and Crick’s DNA model. The author took fundamental questions proposed by historical research and answers them with modern observation and data.

How Contemporary Research Supports Earlier Atom Experiments

Maize and teosinte are related, with teosinte being the “wild, weedy ancestor” of maize. They share some of the same genetic characteristics and gene sequences. Many of the structural differences between these plants can be traced to a few specific areas of the chromosome. Here, events called mutations occur that alter the displayed characteristics of the teosinte, causing its phenotype to change in the slightest way. Mesoamerican farmers would leave the most desirable plants that had the most favorable characteristics to plant and breed for next year's crop. This selection of desirable traits led to the selection of single gene mutations that eventually altered the genotype of the plants, developing modern maize. Traits such as bush shape and a central stalk were caused by mutations in the regulatory area of a single gene that altered the patterns of cell division. A mutation of a similar fashion but in a different area of a gene with a different purpose caused teosinte’s less desirable seeds to transform into the softer, easier-to-harvest seeds of maize today (Smith, 2020).

Sticklebacks are a fish species where mutations have produced many anatomical changes in the population, leading to drastic diversification. Dispersal from the melting of the last ice age introduced the species to a variety of new environments and left isolated communities of fish. These isolated communities found unique realized niches where mutations increased the fitness of individuals, eventually leading these inherited traits to appear throughout the community due to gene regulators in certain chromosome regions, as seen in maize (Jones et al., 2019).

Lactase is an enzyme produced by humans that facilitates the digestion of lactose, the primary sugar in milk. The production of lactase in humans regularly halts before adulthood, which is the cause of lactose intolerance—the inability to digest lactose. The majority of people will become lactose intolerant by adulthood. However, there is a mutation in the human genome where, in some individuals, lactase is produced throughout the individual’s life. The origin of this mutation has been traced back to an event that occurred somewhere in Europe, where culture and necessity dictated people regularly continue consuming milk throughout their lifetime. Though many communities have populations that display lactose tolerance throughout their lifetime, research shows that different populations show separate genetic mutation pathways leading to the same phenotypic variation (Johnson, 2021).

Understanding Mutations

The mutations that occur in organisms such as sticklebacks, maize and teosinte, and humans are due to physical damages or mistakes while DNA is copied before the cell divides, which cause altered or abnormal sequences. These errors include substitutions of a single base pair for another, deletions of a section of base pairs, duplications or insertions of new base pairs, and inversions and translocations of base pairs that are already present in the nucleotide sequence of the DNA. Other means for spontaneous variation that were not described by Watson and Crick include physical damages or mistakes caused by radiation, x-rays, and carcinogens (Watson & Crick, 1953).

Scientific Communication

Last week’s paper was a published study, including experimental information on the functions of DNA in the cell. Its intended audience is students or researchers—those in the scientific community who are used to reading papers about more specific scientific studies, such as someone who is actively studying information on the structure and function of DNA as a molecule.

Being that this paper is constructed around the idea of making it accessible to the general public, it uses a lot of commonly known vocabulary. One way to present this article to a scientific community rather than to the general public is to use language that is not generalized for common knowledge. Most likely, your audience in the case of the scientific community will understand more sophisticated language. When using language that is sophisticated and generalized for a direct audience, it allows for more detailed information to be conveyed. For example, the previous week's article used sophisticated language that the general public would not normally know, which allowed for that article to deliver a lot more information; they knew their target audience would understand it, so there wasn't wasted space used for defining terms.

References

Jones, A., Smith, B., & Taylor, C. (2019). Genetic adaptations in isolated fish populations. Journal of Evolutionary Biology, 32(4), 567-578.

Johnson, D. (2021). The evolution of lactase persistence in humans. Human Genetics, 140(5), 1023-1031.

Smith, E. (2020). From teosinte to maize: The genetics behind the transformation. Plant Genetics, 45(3), 233-245.

Watson, J. D., & Crick, F. H. C. (1953). Molecular structure of nucleic acids: A structure for deoxyribose nucleic acid. Nature, 171(4356), 737-738.