This year marks the tenth anniversary of the complete human genome sequence. The Human Genome Project revealed a surprising fact: Only 1% of our genome encodes proteins. This equates to a paltry 20,000–25,000 genes. The function of the other 99% of our DNA remained a mystery. Shortly after the sequencing was completed, the National Human Genome Research Institute (NHGRI) launched a new research project, termed the Encyclopedia Of DNA Elements (ENCODE), to identify DNA elements and try to find a purpose for the other 99% of our DNA. This project has contributed greatly to our understanding of the human genome, as documented in the 30 ENCODE-related papers published in Nature, Genome Research and Genome Biology in 2012 (see the Nature web site. However, the ENCODE project is being used in an unforeseen way: to support an appeal to the recent US Supreme Court decision about the constitutionality of collection and analysis of DNA from arrestees.
The ENCODE project has revealed a genomic landscape littered with protein-coding regions, regulatory elements, noncoding RNA sequences, pseudogenes, protein-binding sites and sequences of epigenetic importance such as CpG islands and sites of DNase I hypersensitivity and DNA methylation. Scientists now estimate that 80% of the human genome has some function, and we are learning that “junk” DNA is not really junk after all. The 99% of our genome that has been ignored historically may be more important than we’ve been lead to believe.
Part of the argument being used in the legal appeal is that even seemingly innocent loci, such as short tandem repeat (STR) loci used for forensic casework, may provide some personal information about the DNA donor and that this constitutes an invasion of privacy. Based on the ENCODE finding that most of our genome has function or is associated with functional areas, lawyers are now arguing that in the future, as scientists learn more about DNA sequences that direct our biology, even STR loci may turn out to be more informative than we realize today. The counterargument is that there is no evidence to show that forensically relevant STR loci have predictive value or are associated with a particular phenotype such as a disease state. Even the TH01 locus, which can affect expression levels of tyrosine hydroxylase, provides no phenotypic information about the DNA donor. Furthermore, phenotypic outcomes, such as the development of a disease or possession of a certain behavior, are genetically complex, limiting the predictive value of a single locus.
With the recent US Supreme Court ruling and the subsequent appeal, this issue has been thrust onto an international stage. At the upcoming International Symposium of Human Identification (ISHI), which being held in Atlanta, Georgia, October 7–10, legal experts and experts in the field of forensic science will present both sides of the argument and debate the topic. Although I do not expect these panel members to come to an agreement about the implications of the ENCODE project or the next steps policymakers need to take to minimize privacy concerns, I do expect a well presented and passionate discussion from both sides. To learn more about this ENCODE panel, visit ISHI news.