A Genome-Wide Assessment of Short Insertion and Deletion Variation in African-Americans

Two main types of DNA sequence variation in humans are variation in the sequence itself, and variation in sequence length by insertions or deletions (InDels). Small InDels in a protein-encoding gene may lead to protein dysfunction or premature termination.  Research on InDels has focused primarily on select targeted genes; however, sequencing technology now makes it possible to measure InDels across entire genomes. Understanding InDel frequency, characteristics and distribution is a first step in understanding their contribution to human physiology and disease.  In this assessment of common InDels across exomes and flanking DNA of fifty-four African-Americans having abnormal blood pressure, individuals averaged approximately 11,000 InDels; seventy percent were deletions relative to the human reference sequence. To investigate the relationship of InDels with blood pressure in African-Americans, InDel distribution is now being analyzed in seventeen previously identified hypertension-susceptibility genes.  A simple summary will be given at my presentation, but these analyses are ongoing. These data are the first survey of insertion and deletion variation across the genome of African-Americans, and they are a first step toward understanding the role of such variation in human disease.