No effect on chromosomal products. Crossover products have deficiencies and duplications, which are lethal and do not give rise to viable progeny. Again, the appearance of reducing crossing over is an effect of the inversion. The genetic results of crossing over within inversion loops make it seem that crossing over has been suppressed because the products of crossing over are lost. Thus, inversions are often described as crossover suppressors , decreasing what is usually thought of as the standard amount of recombination.
Inversions cause partial sterility .
Thus, they seldomly should be established in nature. There are, however, important exceptions. In these organisms, paracentric inversions do not lower fecundity. Crossing over does not occur in males , so the output of sperm does not suffer. Each karyotype represents a different arrangement of genes.