Three Foxg1 Genes in Lampreys: The Heritage of Whole-Genome Duplications at the Early Stages of Vertebrate Evolution

The foxg1 gene has been described as one of the key regulators of early differentiation and development of the vertebrate forebrain and related sensory organs. In this article, the authors describe for the first time the presence of three foxg1 paralogs in lampreys, representatives of Agnatha, one of the most evolutionarily ancient branches of vertebrates. While maintaining several common features, an expression patterns of foxg1 paralogs in lampreys demonstrate elements of spatial subfunctionalization. An assessment of the estimated timing of duplication of foxg1 lamprey genes suggests that these genes could have appeared as a result of two rounds of whole-genome duplications at the early stages of vertebrate evolution.