Meeting Abstract

6.3  Monday, Jan. 4  Evolution of genome size in tetraploid suckers (Catostomidae: Cypriniformes) STANHOPE, B. A.*; BERENDZEN, P. B.; University of Northern Iowa; University of Northern Iowa bstan@uni.edu

Genome size varies among organisms and is often correlated with developmental rate and morphology. It has long been observed that a larger genome size will positively correlate with elongated development periods and larger body size, whereas smaller genomes will be paired with shortened lifespan and specialization of physical features. Catostomidae is a family of freshwater fishes known as suckers. Catostomids descended from a single tetraploid ancestor and its members present a wide variety of body types and maturation periods. Preliminary studies of the Catostomidae have indicated loss of duplicate gene expression. The objective of this study is to determine if a correlation exists between genome content, phylogeny, and biological characteristics. This investigation utilizes single-strand conformational polymorphism (SSCP) analysis of several nuclear genes and feulgen image densitometry for analysis of genome size based on DNA content within red blood cells. SSCP will determine the number of copies of genes in various species of catostomids to determine if duplicate copies are lost or are no longer functional. Results of the SSCP analyses will be used to construct a gene tree to determine the evolution of each gene. Preliminary analyses of the DNA content data suggest that there is a general positive association between genome size and longevity, age of maturation, egg diameter, and body length. The strongest correlation exists between genome size and egg diameter, which is consistent with previous studies of other fishes. Genome size data will be mapped on a phylogeny to test for evolutionary trends.