* Ribosomal RNA (rRNA) genes: These genes are essential for protein synthesis and are highly conserved across different organisms. Comparing rRNA sequences can reveal deep evolutionary relationships.
* Other highly conserved genes: Genes involved in essential cellular processes, like DNA replication and transcription, are also good candidates for comparison.
Why not other molecular comparisons?
* Proteins: While protein sequences can provide information about relationships, they are more likely to evolve rapidly and show less deep evolutionary connections than DNA sequences.
* Carbohydrates: While fungi, plants, and animals have different cell wall structures and carbohydrate compositions, these differences are not as informative for determining deep evolutionary relationships as DNA sequences.
* Lipids: Lipids are highly diverse and not particularly useful for comparing distant evolutionary relationships.
What to expect:
Comparing DNA sequences of key genes will reveal that fungi are more closely related to animals than to plants. This might seem surprising, but it is supported by a large body of evidence from various fields, including molecular biology, cell structure, and biochemistry.
Note: While comparing DNA sequences is the most reliable method, other molecular comparisons, like protein structures or metabolic pathways, can provide supplementary information.
