Understanding SNPs : Single Nucleotide Polymorphisms :: Biology SNP Natural Selection

missing figures Introduction Throughout the 21st century scientists have made remarkable leaps and bounds in the field of human genetics. One particular subject that has recently gained a lot of attention is the development of the human genome. Because of the human genome it is now widely understood that many humans throughout the world have thousands of genes in common. However, there are just as many different forms of variation that take place among humans. For example, genetic variation is noticed through differences in hair color and texture, height, eye color and many other physical traits (phenotype). Another form of genetic variation is called single nucleotide polymorphisms(SNPs). An SNP is simply a location on a DNA chain were ONE nucleotide has undergone a change or variation (morphed). This point of difference represents a single nucleotide polymorphism. It is a location in the DNA helical structure where there is a point of difference in a set of bases. These are what scientist are referring to when they map the human genome and find the loci of SNPs. Scientists are currently studying SNPs for various reasons and now have the ability to designate the location of SNPs in the human genome. Scientists are so intrigued with the study and tracking of SNPs because it can unfold layers of information regarding the variation of particular genes, such as pathogenic genes. In addition, scientists have found that some genes are more variable than others. (Refer to table 1) Furthermore, the study of SNPs helps researchers understand mutations in populations and migratory patterns. However, the most significant contribution that the study of SNPs provides to the scientific world is a greater understanding of Natural Selection. There are examples throughout this paper which demonstrate how Natural Selection is better understood through SNPs. Method Data from the Human Genome Project allowed Dr. Nachman to address the question if nucleotide variation is positively correlated to recombination rates in humans. First, by integrating physical maps of the human genome with genetic maps, the genetic and physical distances between markers could be compared and recombination rate variation could be estimated. Next, nucleotide variability measurements from other studies were compared to determine the level of nucleotide variability in humans. Finally, these data sets were analyzed to determine the correlation between recombination rate in humans and nucleotide variability. Additionally, Dr. Nachman compared correlations between recombination rates and nucleotide variation by looking at data of SNP density obtained from the Human Genome Project. PCR technique is essential to the study of SNPs.