In: Biology
Describe how a mutation in a gene switch can change when/where a protein is expressed. Using an example, describe how that mutation could affect an organism’s fitness.
A gene switch is an operator gene present just infront of the promoter in an operon. Promoter binds to RNA polymerase for the transcription to occur. The operator gene which is the switch to the operon binds to a repressor molecule and can block the path of the RNA polymerase when transcription is not essential in the cell. Pressence of represor attached to operator RNA polymerase path is blocked and there is no transcription occurring. Absence of repressor attached to operator will allow the transcription to occur. Thei way operator controls the transcription.
If a mutation occurs in the operator or switch of the operon, then the repressor may not be able to bind or it may not be able to be separated from operator gene. This affects transcription of a gene. Fitness in terms of genetics is the ability of the organism to add more progeny to the next generation. Every bodily function needs certain proteins to be produced in the body. WHen transcription regulation fails because of the mutation in operator gene, protein synthesis also gets affected. This inturn affectes the reproductive ability of the organism if the operon swich that has mutated is involved in producing reproductive protein.
Sickle cell disease is a mutation where one nucleotide change (point mutation) affects the hemoglobin composition making it sickle shaped RBCs. This inturn affects the amount of O2 the RBCs can carry. This is how it affects the energy levels of the organism.