Atlantic Salmon (Salmo salar) Chromosomes and Speciation

Abstract

The chromosomes of sea‐run Atlantic Salmon from three North American rivers were studied with cell culture preparations. Extensive data from Machias River (Maine) specimens showed a sharp mode of 54 chromosomes. Modes of 55 for the Narraguagus River (Maine) and 56 for the Miramichi River (New Brunswick) represented much smaller percentages of their counts. A relatively constant arm number of 72 indicates a Robertsonian pattern of polymorphism.

Comparative Cytology of <i>Tilapia rendalli</i> and <i>Geophagus brasiliensis</i> (Cichlidae, Pisces)

“…It is known that in most cases fishes have 48 chromosomes (Roberts 1970). Our findings fit the same outline, showing that T. rendalli has a diploid complement of 44 chromosomes and G. brasiliensis has 48.…”

Chromosomes and constitutive heterochromatin distribution in Arctic charr, Salvelinus alpinus (L.) (Pisces: Salmonidae)

“…Fish from other populations in Maine, USA, Sweden and Kamchatka have been found to have 2n = 80, NF = 100 karyotypes (Disney & Wright, 1987;Nygren et aL, 1971;Vasil'yev, 1975). Such a chromosome polymorphism has been found in another species of salmonid, the Atlantic salmon Salmo salar Roberts, 1970) in which fish from Europe were found to have 2n = 58, NF = 74 karyotypes while some fish from North America were found to have 2n = 56, NF = 72 karyotypes.…”

CHROMOSOME-NUMBER VARIATIONS IN THE RAINBOW TROUT (<i>SALMO GAIRDNERII IRIDEUS</i> (GIBBONS))

“…The intraindividual variation of the chromosomes has been recorded in Salmo salar by Roberts (1968Roberts ( , 1970, as well as in Salmo irideus by Ohno et al (1965). Based on the mitotic chromosomes from liver, kidney, spleen, testis and ovary, the latter authors reported a variation in number ranging from 2n, 58 to 2n, 65.…”