The crossover operator explores a new solution space and provides the possibility of generating new solutions called offspring through mating pairs of chromosomes (Pasandideh et al. 2015).
Generally, it chooses two parent chromosomes from a population based on the crowding selection operator described, with a crossover chance, crossover this parents to form new offspring through mating pairs of chromosomes.
The serotype/mating type of the remaining seven AD hybrid isolates could not be determined because of the loss of the mating type chromosome of one serotype (Table 1).
The results show significant support for pre-mating barriers depended on the combinations of specific mating type chromosomes and less obvious signs for post-mating isolation driven by the origins of the mating types.
However we still need a way of accounting for this in the random selection of chromosomes which mate to generate offspring.
The ability of two individuals with different numbers of chromosomes to mate successfully may relate to the presence of pseudolinkage and residual tetrasomy in male salmonids [ 1, 31, 32] that may somehow help to prevent aneuploidy in the juveniles.
As the number of chromosomes in the mating pool associated with smaller costs grows exponentially, after some generations, the T parent chromosomes chosen to mate are eventually almost identical.
Following syngamy, the nucleus serves as a transport capsule to conjunctly move the whole set of chromosomes of one mating cell into close proximity of the partner nucleus (i.e., nuclear congression) [ 10, 12].
Unequal recombination/crossover at the MAT locus between opposite mating-type idiomorphs during the pairing of chromosomes should be the most favorable mechanism to account for the truncated MAT1-1-1 (Gioti et al. 2012).
The NRR of the mating-type chromosomes contained genes of the same distribution, with the exception of 2-fold elevated density of small secreted proteins (SSPs) and, in particular, a 5-fold enrichment of Cys-rich SSPs compared to the autosomes.
