Question

Genes that have homologs in a variety of species have been discovered through the analysis of genome sequences. In fact, it is not uncommon to find a family of homologous genes encoding proteins that are unmistakably similar in amino acid sequence in organisms as diverse as budding yeast, archaea, plants, and humans. Even more remarkably, many of these proteins can substitute functionally for their homologs in other organisms. Explain what it is about the origins of cells that makes it possible for proteins expressed by homologous genes to be functionally interchangeable in different organisms.

Answer 1

The origins of cells allow proteins expressed by homologous genes to be functionally interchangeable in different organisms. Factors such as the common ancestry of all living things, the use of the same amino acids, and the evolution of protein function contribute to this interchangeability.

Step-by-step explanation:

The origins of cells play a crucial role in making it possible for proteins expressed by homologous genes to be functionally interchangeable in different organisms. The early selection of the same 20 amino acids and the common ancestry of all living things are factors that contribute to this interchangeability. Evolution of protein function occurs through recombinatorial exchange of DNA segments and the accumulation of base substitutions in redundant genes. Additionally, alternate splicing of RNA variants and repurposing of useful regions of protein structure contribute to the production of new proteins without adding new genes to a genome.