Chapter 26.5: Horizontal Gene Transfer By Maria Waterhouse

Horizontal Gene transfer Before, vertical evolution has been thought as the normal way Now, horizontal gene transfer has come into play Any process by which an organism incorporates genetic material from another organism without being the offspring of that organism.

Genomes and proteomes Connection Horizontal gene transfer helps species evolve “Tree of life” becomes “web of life” Traits transfer through conjugation, transformation, transduction May encode proteins that provide survival advantage Common among unicellular eukaryotes Frequency and importance in multicellular eukaryotes are remains difficult to evaluate

In the Beginning Was it in the earliest stages of evolution? Three domains of life arose from prokaryotic cell. Bacteria Archaea Eukarya Horizontal gene transfer may have been common during those stages Could be that the universal ancestor was actually an ancestral community of cell lineages that evolved as a whole. We wouldn’t be able to trace back to a single ancestor Was a prominent way to foster evolutionary change

In the Beginning Was it in the earliest stages of evolution? Three domains of life arose from prokaryotic cell. Bacteria Archaea Eukarya Horizontal gene transfer may have been common during those stages Could be that the universal ancestor was actually an ancestral community of cell lineages that evolved as a whole. We wouldn’t be able to trace back to a single ancestor Was a prominent way to foster evolutionary change

Where is It Now? Eukaryotic cells Multicellularity and sexual reproduction presented barriers to horizontal gene transfer In those organisms, web is more treelike in structure. Have to be transferred when the eukaryotic cell is a gamete, or is a cell that gives rise to gametes.