Discussion
Carl Woese established that short subunit rRNA sequences can be used to reveal evolutionary relationships between various organisms. Based on this, which one of the following options is the established phylogenetic arrangement of the three domains of life?
Answer: C
The established arrangement is tree II: Bacteria branch off first, and Archaea and Eukarya are sister groups.
Comparing small-subunit rRNA sequences, Woese showed that the prokaryotes formed two deeply separate groups, Bacteria and Archaea, and proposed the three domains in 1990. Rooting the tree with pairs of genes that duplicated before the last common ancestor places the root on the bacterial branch, so Archaea share a more recent common ancestor with Eukarya than with Bacteria. Archaea resemble eukaryotes in their transcription and translation machinery, including histone-like proteins and similar RNA polymerases.
Tree I makes Bacteria and Eukarya the sister groups, tree III pairs Archaea with Bacteria (the old prokaryote grouping that Woese overturned), and tree IV draws Archaea as the ancestor of the other two, which the rRNA data do not show.
Post your comment
Please log in or register to post a comment.
Examination Categories
- SSC Exams
- Banking Exams
- Teaching Exams
- Civil Services Exams
- Railways Exams
- Engineering Recruitment Exams
- Defence Exams
- State Government Exams
- Police Exams
- Insurance Exams
- Nursing Exams
- Other Government Exams
- NRA CET
- PG Entrance Exams
- Campus Placement
- MBA Entrance Exams
- CUET and UG Entrance
- Judiciary Exams
- Regulatory Body Exams
- Software Development