Evolvability And It’s Implication In Drug Design
The ability of viral and bacterial pathogens to develop antibiotic resistance is a combination of natural selection and evolvability. The application of antibiotics to bacterial populations places them under a stressful environment. Bacteria and viruses are prokaryotes and therefore a lot of their genetic material is composed of RNA. RNA is genomically unstable and has a much higher mutation rate than DNA.
It is because of this fact that it is quite likely that a mutation can occur within the population that confers to antibiotic resistance. This particular strain will thus survive, and will pass on the advantageous gene to other strains within the population through plasmid exchange. And the population evolves through natural selection. Many problematic diseases today have developed antibiotic resistance through this type of method, for example the influenza virus, HIV and MRSA super bug (methicillin-resistant Staphylococcus aureus) (Creavin 2004).
Because of evolvability, evolution and natural selection have an effect on antibiotic resistance; they have an appreciation in drug design. By understanding the mechanism of evolvability scientists can develop therapies that strive to modify the variability of these virulent pathogens and their ability to develop resistance strains so easily (Creavin 2004). Also anticipating the evolutionary potential of various strains will allow for effective procedures to be implemented preventing pandemics and epidemics (Creavin 2004).
But the situation of evolvability and evolution is not as streamlined as one may assume, which has been discussed earlier in regards to robustness and neutrality. The same situation comes into effect here. Bacterial and virulent strains evolve at different rates and most likely use different mechanism for evolvability. This has been shown by experiments conducted by Lindquist and true (2000) on the [PSI+] prion in yeast strains and the research done Rutherford and Lindquist (1998) into the mechanism of evolvability in Hsp90 protein within drosophila. Both showed different mechanisms to evolvability.
Moreover the rate of evolution in bacterial and virulent strains is not going to be at a constant rate and, different treatments and drugs will have different effects on selection (Creavin 2004). It is understood that when antibiotics are used against pathogens, this places them under selective pressures which enhances their evolvability mechanisms (Earl et al, 2004). All of these are imperative factors which will be hopefully be implemented during drug research and design. The fact that evolvability is a relatively young topic which is still developing rapidly means that there is still a long way to go before treatment methods that can manipulate the mechanism of evolvability can by fashioned.
