 Intergenomic exchanges are often lethal due to the fact that chromosomes in unisexual species are homeologous (similar, but less so than homologous chromosomes from within a species).Homologous chromosomes are largely identical, in this case as a result of the chromosome replication.Gynogenesis is a form of parthenogenesis where an egg begins to divide only after being pricked by a sperm cell, but without the genetic material of the sperm being used.