BIOL 112 1nd Edition Lecture 13 Outline of Last Lecture I Lecture cancelled Outline of Current Lecture II III IV V Homologous sequences Use different types of genes for comparing different organisms Beware of misinterpreting analogy as homology Molecular homology vs analogy Current Lecture Homologous sequences o Orthologs Tend to have high sequence identity May may not have same function Ex Sequence from species A Compare to genome data base for all genome 8 identities approximate to 80 identities 11 total population o High so high the two genes are probably homologs Use different types of genes for comparing different organisms o For organism likely to be distantly related ex Human vs bacteria use slow evolving sequences o Slow evolving means doesn t change over time Don t change because changes likely to be detrimental o For organisms that are closely related use fast evolving sequences o Slow evolving sequences will show no difference between closely related organisms o Fast evolving sequences will be different between e g Races or strains within a species Evolve changes rapidly because not essential for function Ex Comparison of human ethnic groups compare hyper variable region of mitochondrial genome Beware of misinterpreting analogy as homology o Distinguish between the two by looking for many points of characteristic initially compared These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Molecular homology vs analogy o If homologous sequence identity high 50 o If analogous low sequence identity about 25
View Full Document
Unlocking...