What are the major weaknesses of the parsimony and distance matrix methods of phylogeny reconstruction?
What will be an ideal response?
The main problem with parsimony is that, by definition, it assumes the most parsimonious (shortest or simplest) evolutionary pathway, while it is almost certainly true that this is not invariably the pathway taken. Still, as a guiding principle, parsimony has much to recommend it. Distance methods make no such assumptions about how evolution should work, but on the other hand assume that simple unweighted similarity and dissimilarity reflect evolutionary relatedness and that evolutionary rate is constant across lineages. We know that this is not true, owing to selective constraints, convergence, etc.
You might also like to view...
DNAase is an enzyme that catalyzes the hydrolysis of the covalent bonds that join nucleotides together. What would first happen to DNA molecules treated with DNAase?
A) The two strands of the double helix would separate. B) The phosphodiester bonds between deoxyribose sugars would be broken. C) The purines would be separated from the deoxyribose sugars. D) The pyrimidines would be separated from the deoxyribose sugars. E) All bases would be separated from the deoxyribose sugars.
A rare disease is now understood to be caused by a single mutant gene. When the researcher learns that the gene encodes a ________, he says "Oh good! We may be able to treat the disease with recombinant protein produced in E. coli and delivered by injection."
A. ribozyme B. protein hormone C. component of chromatin D. mitochondrial enzyme E. cell-surface receptor
Without using chemical agents, name two examples of how the bacterial cell wall can be damaged that would result in Gram-positive bacteria showing a Gram-negative result
What will be an ideal response?
What principal accomplishment of Pasteur's work was essential to refute the spontaneous generation theory?
a. bacterial isolation techniques b. developing nutrient agar plates for culturing microorganisms c. development of the light microscope d. sterilization