The Structure of Survival

Last blog entry I wrote about a topic I discussed in class and how that related to the importance of DNA and what chapter two of The Selfish Gene says about it. The frequency of discussing DNA and evolution in my biology class made me want to mention few things I've learned to discuss chapter three. During this chapter, Hawkins assesses the definition of the term gene. He decides to use G. C. Williams' definition, "A gene is defined as any portion of chromosomal material that potentially lasts for long enough generations to serve as a unit of natural selection"(pg. 28). Later on, Hawkins says, "But even a close relative is unlikely to share a whole chromosome with you. The smaller genetic subunit is, the more likely it is that another individual shares it--the more likely it is to be represented many times over in the world"(pg. 31). This made me think of the importance of gene expression in the idea of survival of the fittest, as we might all have similarities in DNA but how we express our genetic material is what matters. 


Species that have evolved in many different eras all share genes or structure in DNA, but how that express it, or whether they express it, determines their survival. I find it amazing how evolution has shaped our DNA sequences to make it perfect for survival in every situation. Evolution is something that's happening all the time, being affected by outside stimuli and how genes affect each other. 
Recently in my biology class I did some reading in cleft palate. This relates to evolution as it shows how DNA always has to be evolving because as it does, the definition of fittest changes. 

Msx1 protein

Scientists have still a lot to research on cleft palate but from what they know, it's human genetic factors which cause it. Cleft palate is very related with a gene called Msx1, which is responsible for the Msx1 protein. Different human factors, like other genes or the amount of folic acid con sued during pregnancy affect this condition. According to an article I read about this condition, "The research team performed a battery of evolutionary analyses on 46 Msx proteins from a diverse collection of animals, ranging from sponges to humans. This analysis identified human sequence variants in Msx likely to underlie disease, and indicated why mutations in the same gene can lead to either orofacial clefting or ectodermal dysplasias." What this basically means is that the Msx1 gene is present in many species but how humans express it and the factors affecting the expression might cause cleft palate. As Hawkins says in pages 30 and 31, we can share genetic units with everyone but through natural selection or survival of the fittest, the most competent type of gene expression will prevail. 

As proteins are what makes up our bodies, gene expression is very important in natural selection.

As in my previous blog entry, I will use this observation on genetics to try to show evidence for evolution. Dawkins says, "The true purpose of DNA is to survive, no more and no less." The DNA from the earliest ancestor of evolution has found its way through billions of years to survive generation by generation. Mutations have made it change, but overall it maintains a similar functioning, with the same structure. In natural selection DNA mutations that change its expression and probability of survival matter, as it eventually causes new species to emerge. Our different appearances are ways our DNAs disguise to survive. Evolution is the processes in which DNA mutates to create better genes and gene expression to survive the most. So going back to the cleft palate case, organisms are very similar. We share characteristics in our DNA with sponges, so a process like evolution caused by natural selection must have made gene expression change.