Dominance of RNA world is proved by:

1. Capping
2. Splicing
3. Polyadenylation

Explanation:

The RNA world hypothesis proposes that RNA was the first self-replicating molecule that existed before the emergence of DNA and proteins. RNA molecules are capable of storing genetic information, catalyzing chemical reactions, and replicating themselves, making them a likely candidate for the first life form on Earth. The following features of RNA provide evidence for the dominance of the RNA world:

1. Capping: The 5' cap structure is a modification of the 5' end of mRNA molecules that is essential for the process of translation. The cap protects the mRNA from degradation and helps to recruit the ribosome to initiate translation. The cap is added by the enzyme guanylyltransferase, which uses GTP as a substrate. The cap structure is found in all eukaryotic mRNA molecules, indicating that it is a conserved feature of RNA-based life forms.

2. Splicing: Introns are non-coding regions of DNA that are present in eukaryotic genes. These introns are removed by a process called splicing, which involves the excision of the intron sequence and the joining of the remaining exons. The splicing process is catalyzed by RNA molecules called spliceosomes, which are composed of small nuclear RNAs (snRNAs) and proteins. The fact that RNA molecules are capable of catalyzing splicing reactions provides evidence for the dominance of the RNA world.

3. Polyadenylation: The 3' end of eukaryotic mRNA molecules is modified by the addition of a poly(A) tail. This modification is important for the stability of the mRNA and for the initiation of translation. The poly(A) tail is added by the enzyme poly(A) polymerase, which uses ATP as a substrate. The poly(A) tail is a conserved feature of eukaryotic mRNA molecules, indicating that it is an important feature of RNA-based life forms.

Conclusion:

The features of capping, splicing, and polyadenylation provide evidence for the dominance of the RNA world hypothesis. These modifications are essential for the function and stability of mRNA molecules and are conserved features of eukaryotic cells. The ability of RNA molecules to catalyze these reactions suggests that RNA was capable of performing many of the functions that are now performed by proteins, supporting the RNA world hypothesis.

Splicing is the process known as dominance of rna world..