Unless you are an identical twin, have you ever seen anyone else that looks exactly like you? Even as a twin, there are noticeable differences between the two people. How can this be possible while still sharing so many of the same genes? There is variation within every species as the genetic makeup of each organism influences the different phenotypes that we are able to observe. It isn’t as simple as just having a set of genes that correspond to a certain phenotype though. Genes provide the framework and ability to possess certain characteristics, but the real question is what genes will be expressed and to what extent they will be expressed. Phenotypes are at the mercy of the regulatory processes of genes. Each individual may possess some genes that aren’t regulated, and if they aren’t turned on then they will never be expressed. Only expressed genes will result in visible traits in an organism. As organisms evolve, we are able to observe changes in morphology, physiology, and behaviours. These adaptations don’t just appear in the phenotype, but have to start at the genes themselves. We always refer to natural selection as a tendency towards a specific trait, but we should really look deeper and find the root of these changes. Associate Professor Peter Dearden, Director of Genetics Otago, (Genotype/ phenotype connection, 2011) has done research on the matter, and believes that genes may not actually be the initial source of evolution. From his research, he concluded that the way genes interact with one another may be changing and this is what results in the differences in gene expression (Genotype/ phenotype connection, 2011). Barrier et. al (2001) have also compared evolutionary changes in phenotype to the genetic makeup of organisms. They believe that regulatory genes may be the source of such noticeable changes in organisms (Barrier et. al, 2001). With these findings, it appears that the focus shouldn’t necessarily be on the different genes an organism has, but rather how each of the genes they do have function and how this corresponds to different phenotypes.

 

References:

Barrier, M, Robichaux, R, Purugganan, M 2001, ‘Accelerated regulatory gene evolution in an adaptive radiation’, PNAS, vol. 98, no. 18, pp. 10208-10213.

The genotype/ phenotype connection 2011, Science Learning Hub- The University of Waikato, viewed 6 March 2014, <http://www.sciencelearn.org.nz/Contexts/Uniquely-Me/NZ-Research/The-genotype-phenotype-connection>.