Part I. The Big Tree of Life 1) What is a molecular chronometer? List the desired characteristics of a “good” molecular chronometer. Molecular chronometers are macromolecules such as DNA, RNA, or protein that can be sequenced and their sequences compared in different organisms to give an estimate of the phylogenetic relatedness of the organisms. Knowing the mutation rate of the particular gene or relating the organisms to one another in the fossil record allows points of phylogenetic divergence to be dated. UNIVERSAL DISTRIBUION IN ALL ORGANISMS CHOSEN FOR STUDY FUCTIONAL HOMOLOGY, I.E. IDENTICAL FUNCTION IN EACH ORGANISM ALIGNABILITY IN REGIONS OF HOMOLOGY APPROPRATE RATE OF CHANGE FOR EVOLUTIONARY DISTANCE MEASURED 2) Why is it important to have both variable and constant regions in the sequence of a molecular chronometer? If you were comparing two distantly related organisms, would you want the sequences to be relatively constant, or highly variable? To compare organisms that are closely related, you would look at variable regions
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This note was uploaded on 07/13/2008 for the course BIO 2900 taught by Professor Ghiorse during the Spring '07 term at Cornell University (Engineering School).