A Biochemical and Cytological Study of the Longnose Sucker (Catostomus catostomus) and Large and Dwarf Forms of the White Sucker (Catostomus commersoni)

White (Catostomus commersoni) and longnose (C. catostomus) suckers possess diploid complements of 98 chromosomes, including metacentrics, submetacentrics, and acrocentrics. White sucker karyotypes differ consistently from longnose karyotypes by the presence of an additional four metacentrics. The karyotypes of the size and age at maturity of variants of white suckers were indistinguishable. Biochemically, longnose and white suckers are distinctive with respect to muscle myogens, hemoglobins, serum esterases, serum and muscle lactate dehydrogenases, and serum transferrins. The last group of proteins provides a clear genetic separation of the large-sized, late-maturing, and the dwarf, early-maturing white suckers. The former is polymorphic for serum transferrins.