Fondon, III, assistant professor in the University of Texas at Arlington's Department of Biology delivered a talk, "Slippery Genomes-Investigating the Roles of Tandem Repeats in Genomic Plasticity," in the Virginia Bioinformatics Institute (VBI) at Virginia Tech Conference Center on Thursday, July 15.

Fondon's research centers on the molecular origins of heritable phenotypic variation, and how changes in mutation rates and spectra influence patterns of intra- and interspecific variation.  One area of focus is high frequency mutations, especially tandem repeat mutations (microsatellites), and their potential as an abundant source of common phenotypic variation. Tandem repeats are common in the genes of mammals, causing morphological transformations and responding rapidly to selection.  

According to Fondon, "This suggests that repeat mutations could be a useful source of morphological variation. But the question is, ‘Are they?'" 

Fondon discussed his research on the domestic dog, which serves as a microcosm of mammalian evolution. Although breeds have shallow gene pools, they can evolve very rapidly and, as Fondon explains, "Dogs' responsiveness to selection seems limitless." He described his efforts to explore the significance of repeats as a source of common phenotypic variation using candidate-based genetic association studies and comparative phylogenomics, which suggests that the ancestral canid genome was predisposed to the increased production of this specific form of variation. 

Fondon's key take away messages were:


  •     Good phenotypic data are just as important as good genotypic data for genetic association studies, but this is often not put into practice


  •     Tandem repeat variations contribute to dog phenotypic diversity


  •     Repeat interruptions are often removed by slippage mutation



  •     Dog tandem repeats are relatively abundant and pure (have fewer interruptions) compared to humans and other mammals, but these differences are not the direct result of selection


  •     Elevated purity is a derived characteristic of canids - reflecting a change in genomic stability that has been unfolding over millions of years and might contribute to the ability of canids' striking adaptive radiation




    Susan Bland
    Public Relations Practitioner
    Virginia Bioinformatics Institute at Virginia Tech

Published by Susan Bland, July 19, 2010