This week I will continue to utilize the UCSC Genome Browser ( http://genome.ucsc.edu/ ), this time using the Repeat Masker track to research the repeat elements of the PIR gene (Kent, Sugnet, Furey, et al., 2002). Repeat elements are sections of the genome that repeat themselves within the genome. The Screen Masker track is capable of displaying 10 separate classes of repeats: SINE, LINE, LTR, DNA, Simple, Low Complexity, Satellite, RNA, Others, and Unknown. Within each of these classes, areas of the PIR gene are shaded from a light grey to a very dark grey to indicate how many “Base mismatches, base deletions, and base insertions [are] associated with a repeat element,” with a higher number of these being indicated by light shading, while a lower number is indicated by darker shading. Utilizing this knowledge we can see that classes such as LINE and LTR have relatively high concentrations of repeats and classes such as LINE and DNA contain longer repeats. Understan...