Chromosome size in salmon and trout

Cryptic Choice of Conspecific Sperm Controlled by the Impact of Ovarian Fluid on Sperm Swimming Behavior

“…Because male salmonids can be fertile for a much longer time window than females, and greater than 15 days (Yeates 2005 ), the potential for hybridization between salmon and trout within the same river systems is evident (Garcia de Leaniz and Verspoor 1989 ; Hindar and Balstad 1994 ). Despite the ease of generation of salmon–trout hybrids, which can be fertile (Garcia-Vazquez et al 2004 ), they do not represent longer term prospects for successful introgression and have very different chromosome numbers ( S. trutta : 2 n = 80, S. salar : 2 n = 58 [typically], Pegington and Rees 1967 ). Because of these significant reproductive costs of hybridization (Barton and Hewitt 1989 ; Garcia-Vazquez et al 2002 ), selection is predicted to favor postmating female adaptations that avoid fertilization by genetically incompatible sperm (Coyne and Orr 2004 ).…”

A review of factors which may influence the sea‐age and maturation of Atlantic salmon Salmo salar L.

“…There is evidence, both from studies of chromosomes (Svardson, 1945;Roberts, 1970) and of protein polyniorphisms (Bailey et al, 1969;Wilkins, 1972b) that salmonids have evolved through polyploidization; they are thought to be tetraploid. Some doubt has been cast by Rees on the chromosome evidence in the light of the constancy of the amount of nuclear DNA and the structural irregularities between chromosomes of salmonids which have widely differing numbers of chromosomes (Rees, 1964(Rees, ,1967Peginton & Rees, 1967). They suggested that structural changes of the chromosomes (e.g.…”