How to break Mendel’s laws? The role of sexual conflict in the evolution of unusual transmission genetics

Under Mendelian inheritance, individuals receive one set of chromosomes from each of their parents, and transmit one set of these chromosomes at random to their offspring. Yet, in thousands of animals Mendel's laws are broken and the transmission of maternal and paternal alleles lose their symmetry. A large body of theory suggests that these asymmetries might arise because of maternal–paternal genetic conflict, but empirical tests are sorely needed to test whether the plausible is actual.This proposal aims to understand why, when and how the transmission of genes from one generation to the next deviates from Mendel’s laws. We ask how different types of sexual conflict -- both directly between parents (interlocus sexual conflict), indirectly between the parent’s genes within their offspring (intragenomic sexual conflict), and between genes expressed in males and females (intralocus sexual conflict) -- can affect the evolution of non-Mendelian reproduction. We focus on species with extreme reproductive asymmetry known as Paternal Genome Elimination (PGE). PGE males systematically transmit only those chromosomes that they inherited from their mother. This unusual reproductive strategy is thought to originate from a clash of interests between the sexes, where mothers have “won” by monopolizing the parentage of their sons. Although PGE is rarely studied, its repeated evolution and experimental tractability make it an ideal test case for understanding the role of sexual conflict in the evolution of genetic systems.