show Abstracthide AbstractActin proteins are among the most vital and abundant cytoskeletal elements of a cell. They play critical roles in a wide array of cellular processes including cell division and the regulation of gene expression. To better understand the functional versatility, under this project we have analyzed the regulatory region of the Beta actin gene of the catfish Clarias batrachus. We compared the regulatory region of this gene from three populations of the same fish found in three different diverse ecological systems (a dam, the rivers and a hatchery) to correlate its variability in response to ecological pressures. We also made comparisons to the same gene in three sister species (C. gariepinus, C. magur and C. dussumieri) to further document structural diversity.