Carl Woese was an important figure in microbial classification and changed our understanding of the evolution and diversity of life. What breakthrough did he make that allowed us to infer evolutionary relationships between organisms?
What assumptions was his breakthrough based on?
What will be an ideal response?
Answer: During the 1970s, Dr. Carl Woese pioneered the usage of SSU rRNA genes for phylogenetic analysis. He realized that SSU rRNA genes could be used to infer evolutionary relationships because they were (1) universally distributed, (2) have the same function in every organism, (3) change slowly over evolutionary time (highly conserved), and (4) of adequate length to provide sufficient information about very deep, or old, evolutionary relationships. He assumed that changes in DNA sequence are reliably passed on to offspring (they are heritable) and that nucleotide changes between two organisms will accumulate over time since they last shared a common ancestor. Homologous sequence comparison thus allows us to infer evolutionary relationships between nucleotide sequences. Genes that are not often exchanged through horizontal gene transfer (such as SSU rRNA or other housekeeping genes) can be used to infer evolutionary relationships between organisms.
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Which of the following statements is true of viral conjunctivitis?
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Compare and contrast the intercellular junctions that allow communication between plant and animal cells
What will be an ideal response?
The best description of the two components of blood is
A. white blood cells and red blood cells. B. formed elements and plasma. C. formed elements and platelets. D. red blood cells and plasma. E. platelets and plasma.