Another form of repetitive DNA are transposable elements . These are sequences of DNA that generally code for certain proteins and have the ability to move around the genome in a process called transposition . There are quite a number of different types of such elements (we will not review them all). The point is that they (like other repetitive DNA) are governed by intragenomic dynamics as well as organismal population dynamics. An example is the P element in Drosophila melanogaster . There are strains of flies that have P elements (P strains) and strains that do not (M strains). When a P male is crossed to an M female the P elements enter the genome of the offspring and jump around causing mutations (this is what we mean by a fluid genome ). A curious observation about P elements is that strains of flies collected from natural populations before 1950 do not have P elements whereas flies collected from the wild after that do have them. A variety of observations indicate that P elements
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This note was uploaded on 11/05/2011 for the course BIOLOGY MCB2010 taught by Professor Jessicadigirolamo during the Fall '10 term at Broward College.