Abstract
Black Flies of the dipteran family Simuliidae are notorious for being harmful biting pests and a major transmitter of the devastating parasite Onchocerca volvulus, which causes Onchocercias, or River Blindness. Conversely, the Black Fly possesses great ecological significance, especially in boreal biomes. Of notable interest is the key role of Black Fly larvae which serve as aquatic prey and suspension feeders. Black Fly larvae utilize silk to facilitate feeding, locomotion, and cocoon production; thus, the ability to produce silk during the larval stages is crucial to Black Fly survival. Despite the necessity of silk in the Black Fly lifecycle, Black Fly silk genetics is currently not well studied. Through this project we aim to bring to light a better understanding of Black Fly silk genetics through the cloning, expression, and characterization of the Black Fly silk genes. Currently, we have cloned, amplified, and sequenced the cDNA of three Black Fly silk proteins of variable size, named p13. p32, and p55. We strongly propose that the cDNA qualify as true silk gene sequences as they are abundant in the codons which code for glycine, alanine, and serine amino acids and possess the characteristic repetitive residue patterns of silk protein. We have also identified several alleles for p32 and p55 silk genes, but only one allele for p13. In the future, we will express the silk genes using the Pichia pastoris yeast system to study the physicochemical properties of the silk protein. Additionally, we have cloned and amplified the genomic DNA of the three silk sequences. We will compare the cDNA and genomic DNA to determine silk gene structure. As a long term goal, we seek to elucidate the evolutionary history of the Black Fly silk genes by comparing the silk genes of Similium vitattum with that of another very closely related silk-producing species, Similium tribulatum.