crosslertilization

Cross-fertilization, sometimes written as crossfertilization, is the fusion of gametes from genetically distinct individuals, producing offspring with a mix of parental alleles. It is a form of sexual reproduction that contrasts with self-fertilization, where gametes come from the same individual or from closely related gametes. Cross-fertilization increases genetic diversity in a population, which can enhance adaptability and reduce the risk of inherited disorders from recessive genes.

In plants, cross-fertilization typically occurs when pollen from one plant fertilizes ovules of another, often aided by pollinators such as insects, birds, or by wind or water. Many plant species possess mechanisms to promote outcrossing, such as self-incompatibility systems or spatial/temporal separation of male and female functions.

In animals, cross-fertilization happens when the gametes of two individuals unite, usually through mating that results in internal fertilization in terrestrial species or external fertilization in many aquatic species. The resulting offspring often exhibit greater genetic variation, which can influence traits related to survival and reproduction.

Evolutionarily, cross-fertilization fosters heterozygosity and can lead to hybrid vigor in some cases. It also often requires more energy and favorable conditions, since mates must meet and reproduce successfully. In breeding programs, deliberate cross-fertilization is used to combine desirable traits from different lines, sometimes producing hybrids with enhanced performance.

Note that fertilization between different species is typically called hybridization rather than cross-fertilization, though some plants readily produce interspecific hybrids through cross-pollination.