Two eukaryotic proteins have one domain in common but are otherwise very different. Which of the following processes is most likely to have contributed to this similarity?
a. Gene duplication
b. Alternative splicing
c. Exon shuffling
d. Random point mutations

Verified step by step guidance

1. Understand the concept of protein domains: Protein domains are distinct functional and structural units within a protein. They can evolve, function, and exist independently of the rest of the protein chain.
2. Consider the process of exon shuffling: Exon shuffling is a molecular mechanism that can create new genes by rearranging exons, which are coding sequences within a gene. This can lead to proteins with new combinations of domains.
3. Evaluate how exon shuffling contributes to protein diversity: Exon shuffling can result in proteins that share common domains while having different overall structures and functions. This process can lead to the presence of similar domains in otherwise different proteins.
4. Compare exon shuffling with other processes: Gene duplication involves copying entire genes, alternative splicing involves generating different mRNA transcripts from the same gene, and random point mutations involve changes in individual nucleotides. Exon shuffling specifically involves rearranging exons to create new domain combinations.
5. Conclude that exon shuffling is the most likely process: Given the presence of a common domain in otherwise different proteins, exon shuffling is the process most likely to have contributed to this similarity by rearranging exons to create new domain combinations.

Key Concepts

Exon Shuffling

Exon shuffling is a molecular mechanism through which new genes are created by rearranging exons, the coding sequences of DNA. This process can result in proteins with new combinations of functional domains, leading to evolutionary innovation. It is a key contributor to the diversity of protein structures and functions in eukaryotic organisms.

Protein Domains

Protein domains are distinct functional and structural units within a protein, often responsible for a particular function or interaction. Domains can be independently stable and can fold into a specific three-dimensional structure. The presence of a common domain in different proteins suggests a shared evolutionary origin or functional similarity, often due to processes like exon shuffling.

Gene Duplication

Gene duplication is an evolutionary process where an organism gains extra copies of a gene, leading to genetic redundancy. This can allow one copy to mutate and potentially acquire new functions while the other maintains the original function. Although gene duplication can lead to protein diversity, it is less likely to explain the presence of a common domain in otherwise different proteins compared to exon shuffling.