Question

Genomic DNA sequences seem to support the idea that the first eukaryotic cell arose from within the _____ lineage.

1) archaeal
2) bacterial
3) viral
4) last universal common ancestor (LUCA)

Answer 1

DNA evidence supports the hypothesis that eukaryotic cells arose from an endosymbiotic gene fusion between an Archaea and a Bacteria, suggesting the archaeal lineage as their more direct ancestor.

Step-by-step explanation:

Genomic DNA sequences provide evidence that the first eukaryotic cell likely arose from within the archaeal lineage. Research by James Lake of the UCLA/NASA Astrobiology Institute suggests that eukaryotic cells developed from an endosymbiotic gene fusion between two species, an Archaea and a Bacteria. This accounts for why some eukaryotic genes resemble Archaeal genes and others resemble Bacterial genes. The presence of Archaeal and Bacterial genes in eukaryotes, and particularly the similarity between the host cell membrane and biochemistry of eukaryotes to those of Archaea, supports the hypothesis that eukaryotic cells are more closely descended from Archaea. However, this topic remains a subject of active research and debate within the scientific community.