Lack of paternal silencing and ecotype-specific expression in head and body lice hybrids.

Paternal genome elimination (PGE) is a non-Mendelian inheritance system, described in numerous arthropod species, in which males develop from fertilized eggs, but their paternally inherited chromosomes are eliminated before or during spermatogenesis. Therefore, PGE males only transmit their maternally inherited set of chromosomes to their offspring. In addition to the elimination of paternal chromosomes, diverse PGE species have also repeatedly evolved the transcriptional silencing of the paternal genome, making males effectively haploid.