ENG, E.W.*; FILOSA, M.F.; AMEMIYA, Y.; COCHRAN, P.; YOUSON, J.H.; Univ. of Toronto at Scarborough, Toronto, Ontario; as Author 1; as Author 1; Saint Mary’s University, Winona, Minnesota; as Author 1: Variation in Lamprey Albumin: A Link to Life History Strategy?

Previous studies in our lab showed that the parasitic, anadromous Petromyzon marinus contains two different albumin molecules, one (AS) that predominates in the ammocoete and early metamorphosis stages, and a second (SDS-1) that is the predominant protein in the serum of adult, spawning stages. However, only one type of albumin (LAS) was found in the non-parasitic, freshwater Lampetra appendix. LAS is immunologically similar to AS and it predominates only in the ammocoete and early metamorphosis stages. No protein immunologically similar to SDS-1 of P. marinus was found in L. appendix adult serum, and there was no one protein that was predominant. These differences in albumin expression may perhaps be adaptations to the difference in life styles of the two species. To further elucidate the relation between the presence or absence of particular albumin molecules in lampreys with their life histories, we examined two members of a paired freshwater Ichthyomyzon species. We expected that the parasitic form would have two albumin-type molecules and that the non-parasitic form would have only one. However, results indicate that both species contain an albumin molecule immunologically similar to LAS, and this is found in both the ammocoete and adult stages. Also, the LAS-like molecules in the adults of both species contain some similar antigenic determinants. Present studies are directed towards the continued analysis of the albumin profile within these species, as well as in other lamprey species. The significance of these results can lead to a clearer understanding of lamprey evolution and to the evolution of life histories in lampreys. This study was supported by NSERC.