Program > Browse abstracts by author > Falcon Francisco

More than 360 million years ago during the Devonian period, a group of lobed-finned fishes undertook the water-to-land transition and became the first group of vertebrates to venture into land: the tetrapods. This transition was enabled by a number of evolutionary innovations which include the transformation of the fish fin into the tetrapod limb and the emergence of a series of novel organs and structures such as the tongue, the bone marrow, the urinary bladder or the second atria of the heart. In this work, we explore what were the genome dynamics at play during the birth of these new organs and scrutinize the hypothesis that transposable elements might have driven the evolution of their tissue-specific cis-regulatory elements. To this end, we have generated a new assembly for the giant Axolotl genome (Ambystoma mexicanum, 32 Gbp) and have aimed to comprehensively characterize its repeat content. These analyses have revealed that the Axolotl genome harbors an extremely diverse collection of transposable element families spanning all major classes and that their genome has grown to such a huge scale due to the retention of ancient repeats. We are currently in the process of accurately dating these transposable element insertions and determining whether they played any role in catalyzing the emergence of the major tetrapod evolutionary innovations. Furthermore, salamanders such as the Axolotl are unique among tetrapods in that they possess the fascinating capacity to regenerate nearly every organ throughout their lives. Why is this the only tetrapod taxon harbouring such a striking regenerative potential and whether this holds any relationship with their exceptional TE-content remain outstanding questions in regenerative research.