crossspecies

Cross-species is a term used in biology and related fields to describe phenomena, studies, or processes that involve two or more species. It encompasses interactions, comparisons, and the transfer of genes, information, or pathogens across species boundaries. The concept is applied in ecology, genetics, medicine, and conservation to understand how species relate to one another and to humans.

Cross-species transmission refers to the movement of pathogens from one species to another, a major concern in public health and wildlife disease ecology. Zoonoses describe infections that originate in animals and can spill over into humans or other species. Factors influencing spillover include ecological interfaces such as habitat disturbance, close contact through farming or wildlife trade, and viral or microbial adaptation to new hosts.

Interspecific hybridization is another form of cross-species interaction. It occurs when individuals from different species mate and produce offspring, typically among closely related species. Examples include the mule (donkey and horse) and, in some cases, ligers or tigons (lion and tiger). Hybrid fertility is often reduced due to genetic incompatibilities, but exceptions exist; the biological and ethical implications of hybrids are topics of ongoing study.

Cross-species research and translational science use models from multiple species to study biology and disease. Model organisms such as mice, fruit flies, and zebrafish help illuminate genetics, development, and neuroscience relevant to humans. Cross-species genomics and comparative biology reveal conserved and divergent pathways, though researchers must account for species-specific differences when interpreting results.

In ecology and conservation, cross-species interactions shape community structure and ecosystem function. Predation, mutualism, competition, and the introduction of species into new ranges can cross species boundaries and influence biodiversity, ecosystem resilience, and management strategies.