Article Reflection No. 66 (9/2/2023)

Article: “Humanity’s Ancestors Nearly Died Out, Genetic Study Suggests”

Reflection:

In the article “Humanity’s Ancestors Nearly Died Out, Genetic Study Suggests” by Carl Zimmer, the journalist details a new genetic study that claims that humans’ ancestors almost went extinct approximately 930,000 as a result of sudden dry, cold climates. This study, conducted by researchers in China, sheds light on a possible explanation for the lack of human remains found between 650,000 to 950,000 years ago. In regards to significance, the finding suggests that climate change sparked a “bottleneck”, resulting in modern humans and Neanderthals (two lineages). As advancing technology has allowed for more complex DNA analysis, genomes are the focus of this study. With the creation of FitCoal, a method used to model evolution over long periods of time, scientists involved in this new study collected data from fifty different populations (3,154 individuals total). After dissecting the information from the data and FitCoal, the authors concluded that the “bottleneck” prompted a population of 98,000 to shrink to 1,280 until 117,000 years later. However, scientists like University of California, Davis geneticist Brenna Henn and British Museum archaeologist Nick Ashton have expressed reservations about the study’s results, referring to the various factors involved in evolutionary genetic diversity as well as the quantity of human remains outside a country like Africa.

Regarding DNA analysis, how were people able to identify and pinpoint genetic differences without the types of modern microscopes as there are today?