  In the past decade, advances in genome sequencing have allowed researchers to
uncover the history of hybridization in diverse groups of species, including
our own. Although the field has made impressive progress in documenting the
extent of natural hybridization, both historical and recent, there are still
many unanswered questions about its genetic and evolutionary consequences.
Recent work has suggested that the outcomes of hybridization in the genome may
be in part predictable, but many open questions about the nature of selection
on hybrids and the biological variables that shape such selection have hampered
progress in this area. We discuss what is known about the mechanisms that drive
changes in ancestry in the genome after hybridization, highlight major
unresolved questions, and discuss their implications for the predictability of
genome evolution after hybridization.
