Chromosome Cytology in the Cutthroat Trout Series Sal mo clarki (Salmonidae)

Abstract

The karyotypes of two subspecies of the cutthroat trout series, Salmo clarki, were determined from anterior kidney cells. One subspecies, S. c. clarki, the “coa stal” cutthroat, has 2n=68 chromosomes (36 meta or submetacentrics and 32 acrocentrics). The other subspecies, S. c. henshawi, one of the many forms of “inland” cutthroat, has 2n=64 chromosomes (40 meta or submetacentrics and 24 acrocentrics). The fundamental arm number in both subspecies was estimated at 104. Evidently, chromosomal fusions or dissociations have played a major role in the chromosomal evolution of S. clarki. The authors express their appreciation to the many biologists of Regions I, II, and IV of the California Department of Fish and Game for their assistance in collecting the cutthroat trout. We also thank Mr. R. C. Smith of the Animal Sci ence Department at Davis for his help, and Dr. H. J. Price for reading this manu script. This study was supported in part by the California Department of Fish and Game as part of Dingell-Johnson Project California F-28-R, “Trout Genetics,” supported by Federal Aid to Fish Restoration funds. © 1977, Japan Mendel Society, International Society of Cytology. All rights reserved.