Lecture 2: Describing Microbial Diversity: the ... - MCD Biology

More documents

Recommendations

Info

20 A. Doesn’t really matter so long as: 1. “Homologous” gene occurs in all organisms considered a. More specifically, you need to know that the genes are “orthologs,” not “paralogs” b. “Orthologs” share ancestry and retain the same function in the different organisms c. “Paralogs” result from an ancestral duplication, with potentially different functions taken-on subsequent to the duplication – duplications produce “gene families”. d. For instance, the % and & globins are a gene family; they have ancient common ancestry -- the % - type and & - type globins have evolved independently since the ancestral duplication: % - globins are orthologs; & - globins are orthologs. % and & globins are paralogs e. The tree of the gene family would look like:
21 f. If you did not keep your orthologs and paralogs straight (sometimes a tough call) when you build the dataset, you might get some most unexpected (and incorrect) trees, e.g.: You miss the true topology with the restricted data set. better. Human %-globin Mouse %-globin Frog %-globin Human &-globin Mouse &-globin Frog &-globin Human (%-globin) Frog (%-globin) Mouse (&-globin) 2. You need a sufficient number of nucleotides (or amino acids) to be statistically significant -- more is always
Page 1 and 2: Lecture 2: Describing Microbial Div
Page 3 and 4: 3 A. Slowly evolving molecules (e.g
Page 5 and 6: 5 B. Phylogenetic perspective allow
Page 7 and 8: 7 Indeed, the lexicon of biology st
Page 9 and 10: 9 A. Still, “monera” (mostly te
Page 11 and 12: 11 4) Supposition that the eucaryot
Page 13 and 14: 13 3) You cannot meaningfully compa
Page 15 and 16: Note that organism-to-node “dista
Page 17: 17 Vignette - Tree-reading - Baum,
Page 22 and 23: 22 3. Changes must span the evoluti
Page 24 and 25: 24 C. Highly conserved throughout e
Page 26 and 27: B. In essence, the tree is a quanti
Page 28 and 29: 28 Bacteria C. The eucaryote nuclea
Page 30 and 31: 30 H. Note how deeply divergent are
Page 32 and 33: 32 You can download trees, carry ou
Page 34 and 35: 34 C. Most of what we know about ba
Page 36 and 37: 36 B. Environmental sequences have
Page 38 and 39: 38 A. Note that the microbial eucs
Page 40 and 41: 19. The three-domain tree is seen f
Page 42: 42 D. Even enzymes in the same bios
Page 45: Gary Olsen edits the Doolittle tree

Lecture 2: Describing Microbial Diversity: the ... - MCD Biology

Create successful ePaper yourself

Delete template?

Save as template?