1. Obtain a digital image of each of your gels. Label each lane and size of DNA fragment. Don't forget to label the DNA ladder. Interpret the results from your gel. Who is homozygous, heterozygous, gtc for the PV92 insertion. Do you see any "Primer dimers" in your gel? What is a primer dimer? Describe why an Alu element is considered a "jumping gene". What is the molecular mechaniam by which this occurs?Obtain a digital image of each of your gels. Label each lane and size of DNA fragment. Don't forget to label the DNA ladder. 2. Interpret the results from your gel. Who is homozygous, heterozygous, etc for the PV92 insertion. 3. Do you see any "Primer dimers" in your gel? What is a primer dimer? 4. Describe why an Alu element is considered a "jumping gene". What is the molecular mechanism by which this occurs? When you examine the photograph of your gel, it should be readily apparent that there are differences between people at the level of their DNA. Even though you amplified only one site, a site that every one has in their DNA, you will notice that not all students have the same pattern of bands. Some students will have only one band, while others will have two. We use the term allele to describe different forms of a gene or genetic site. For those who have the Alu repeat (they have at least one 715 bp band), we can say that they are positive for the insertion and denote that allele configuration with a "+" sign. If the Alu repeat is absent (a 415 bp band is generated in the PCR), we assign a "-" allele designation. If a student has a single band, whether it is a single 415 bp band or a single 715 bp band, then both their number 16 chromosomes must be the same in regards to the Alu insertion. They are said to be homozygous and can be designated with the symbols" - /-"or" +/+", respectively. If a student's DNA generates a 415 bp band and an 115 bp band during PCR, the student is said to be heterozygous at this site and the designation" +/- " is assigned. A person's particular combination of alleles is called their genotype. See the table below for a quick summary of the allele designations. Possible Bands Allele Designation Genotype Alu Insert 1. One band at 415 bp -/- homozygous No Alu insert 2. One band at 715 bp +/+ homozygous Alu insert present on both chromosomes 3. One band at 415 bp and a second band at 715 bp. +/- heterozygous Alu insert on one of the chromosomes