Meeting Abstract
Organisms living in polar environments are exposed to constant cold temperatures and long periods of darkness. Many species in polar regions experience temperatures that are below their serum freezing point and have independently evolved antifreeze proteins (AFPs). AFPs bind to forming ice crystals and inhibit ice recrystallization, which confers an adaptive advantage to the species that have AFPs. A recent study of the type III AFP gene in the Antarctic fish, Lycodichthys dearborni, showed that the AFP gene arose from the translocation and duplication of another gene (SAS-B). Tandem duplications of the new AFP gene led to a cluster of AFP III genes. A transposable element (TE) is located upstream of the SAS-B and the AFP cluster, suggesting the putative role of this TE in the formation of the AFP gene cluster. In this study, we aim to understand how this important protein (AFP) has evolved in some polar species and whether TEs are involved in this evolutionary process. To answer these questions, we characterized the AFP gene cluster region and analyzed the TEs density in L. dearborni. We identified a highly abundant TE in the AFP cluster that has not been identified for this species before: the L2-1 element. The L2-1 elements are located downstream of each annotated repeat unit of the AFP III gene with a conserved distance suggesting recurrent duplication events. We then further characterized the AFP III genes by examining the relationships among the gene copies and their nearby TE insertions. This analysis should allow dating the duplication events and testing whether TE insertions are involved in the duplication events. This study sheds light on the role of TEs in the evolution and duplication of novel proteins.
