Studies of molecular evolution have provided biologists with new tools to understand the functions of macromolecules and how those functions can change over time. These tools can be used to develop synthetic molecules and to identify and combat human diseases.
learning outcomes
You should be able to:
Describe how studies of molecular evolution are used to understand protein function.
Design in vitro evolution protocols that will generate sequences with desired functional characteristics.
Evaluate evolutionary relationships among viral sequences to understand the evolution and transmission of a viral disease.
How can gene evolution be used to study protein function? Describe a specific example.
Comparisons of evolutionary changes in proteins, made across species in which these proteins differ in function, provide insight into how change in protein sequence relates to change in protein function. For example, changes across many different genes in many different species of puffer fish show which changes are related to the evolution of tetrodotoxin resistance in sodium channel genes. These studies help us understand the function of sodium channels, which helps us understand the genetic basis of various neurological pathologies.
What are the key elements of in vitro evolution, and how do these elements correspond to natural evolutionary processes?
Starting with a large pool of random sequences, in vitro evolution involves rounds of selection and mutation to produce new molecules with specific functions. This corresponds exactly to the processes of mutation and natural selection in natural populations. The only difference is that the selection and mutational processes are controlled by humans in a laboratory setting, to produce a molecule with a desired function.
How are principles of evolutionary biology used to identify emerging diseases?
Most emerging diseases are caused by living, evolving organisms. Evolutionary comparisons of DNA sequences from these pathogens allow quick identification and often reveal the source of the disease (from a particular host species or geographical area). Previously unidentified pathogens can be compared with their closest relatives. This often allows biologists to make predictions about the best strategies for controlling the spread of the disease.
Now that we have discussed how organisms and biological molecules evolve, we are ready to consider the broader evolutionary history of life on Earth. Chapter 24 will describe the long-