Darwin's Idea of Decent with Modification: Speciation

 It is obvious there are compelling evidence to show that evolution has been or is happening. This can be from microevolution, macroevolution, descent from common ancestors, and how earth and life are old. One of my favorite predictions of Darwin’s idea of descent with modification would be speciation, the idea that lineages split and diverge. As a biology major, I have learned much about speciation and one research that particularly struck my attention was the research done by biologist, Leland H. Hartwell, and his research with yeast and somatic mutations with cancer. 

Yeast, or Saccharomyces cerevisiae, has been used for thousands of years for baking bread, brewing beer, and all sorts of other things. Surprisingly, it is also very popular when studying genetics and tells us a lot about the fundamental process of life. Yeast is an easy-to-manipulate, unicellular, eukaryotes. Above shows S. cerevisiae under a microscope. Hartwell used S. cerevisiae, or baker’s yeast to study cancer and the cell cycle (Pray, 2008). With much research, he found that the same genes controlling the cell cycle in baker’s yeast exist in about the same volume as human cells. This result was surprising. “The ancestors of yeast and humans diverge some 1.5 billion years ago” (Albert et al., 2019). Paul Nurse, a geneticist, also found compelling evidence and demonstrated how closely humans and yeast cells are compared to each other. In the picture below shows the similarity of cell division cycle proteins (Cdc) formed in yeast and humans when it comes to their amino acid sequence. “The humans Cdc2 protein is identical to the S. pombre Cdc2 protein in 63% of its amino acids and is identical to the equivalent protein from S. cerevisiae in 68% of its amino acids,” (Alberts et al., 2019). As nurse said in his noble lecture, “We have seen that… cells are formed and grow in accordance with essentially the same laws; hence that these processes must everywhere result from the operation of the same forces,” (Pray, 2008). 

 

Knowing this research, and from countless other scientist, we know humans have diverged from yeast cells some 1.5 billion years ago. With this knowledge, we can better understand cancer in humans and look into ways on how to prevent it. With yeast being an easy-to-manipulate eukaryote, it can give scientists a simpler look into what does on in the cell cycle. “In particular, as Hartwell currently advocates, this information could be used to develop more effective chemotherapy drugs-therapies that intervene with the cell cycle in humans in more precise ways and that can be tailored to particular types of cell cycle mutations,” (Pray, 2008). Having a better understanding of speciation can give us a better idea of what the cell cycle looks like and will likely improve the way we look at cancer, drugs, and cancer therapy. 

Alberts, B., et al. Essential Cell Biology Fifth Edition. New York W.W. Norton & Company, 2019.  

 

Pray, L. (2008) L. H. Hartwell's yeast: A model organism for studying somatic mutations and cancer. Nature Education 1(1):183

 

Creative Biolabs. Saccharomyces cerevisiae (S. cerevisiae) Cell Lines. GMP Creative Biolabs, 2007.