The following questions refer to the phylogenetic tree in Figure 20.3, depicting the origins of life and of the three domains. Horizontal lines indicate instances of gene or genome transfer.
Figure 20.3
A possible phylogenetic tree for the three domains of life.
-Which of these processes can be included among those responsible for the horizontal components of Figure 20.3?

Question

The following questions refer to the phylogenetic tree in Figure 20.3, depicting the origins of life and of the three domains. Horizontal lines indicate instances of gene or genome transfer.
  Figure 20.3
A possible phylogenetic tree for the three domains of life.
-Which of these processes can be included among those responsible for the horizontal components of Figure 20.3?

Quizplus · Accepted Answer

Endosymbiosis is a process of horizontal gene transfer where a free-living organism is engulfed by another organism and establishes a symbiotic relationship within the host cell. This process is thought to have occurred in the evolution of eukaryotic cells, where mitochondria and chloroplasts were originally free-living organisms that were engulfed by a host cell. Therefore, endosymbiosis can be included among those responsible for the horizontal transfer of genetic material in Figure 20.3. Mitosis, binary fission, point mutations, and S phase of the cell cycle are all processes involved in cell division or DNA replication, but they do not involve horizontal gene transfer.

The Following Questions Refer to the Phylogenetic Tree in Figure