Retrotransposable elements: Novel and sensitive DNA markers and their application in human identity

Retrotransposable elements (REs) consisting of long interspersed nuclear elements (LINEs) and short interspersed nuclear elements (SINEs) are a group of markers that can be useful for human identity as well as bio-ancestry testing. SINEs are a class of REs that are typically less than 500 nucleotides long; while LINEs are typically greater than 500 nucleotides and up to several thousand base pair long. The third type of RE is the composite retrotransposon known as SVA (SINE/VNTR/Alu) elements. There are several advantages of RE’s for the application of human identity and bio-ancestry testing. First, the bi-allelic nature of RE's provides technical simplicity of typing two alleles per genetic marker instead of typing an array of nucleotides, sometimes hundreds of nucleotides in length, as with the conventionally used STRs. Secondly, RE's are identical by descent only, making them more stable than other systems in terms of inheritance. In addition, REs do not yield stutter artifacts due to slippage during the PCR, which can reduce some interpretation issues associated with the currently utilized STRs. Until now, however, due to the inherent size difference (>300 bp) associated with insertion and null alleles (or INNULs), the use of REs has not been practical for human identity applications. Although the use of SINEs such as Alu in determining human identity has been studied and reported in the literature, the more than approximately 300 bp size difference between the two alleles prevented development of any useful system. This is the first time any research on the use of