In genetics, transgressive segregation is the formation of extreme phenotypes, or transgressive phenotypes, observed in segregated hybrid populations compared to phenotypes observed in the parental lines.[1][2]
Hybrid offspring generally possess traits or characteristics seen in ancestral species. These traits might be expected to be subdued or diluted when compared to the original species. Transgressive segregation attempts to explain situations when the converse is true, hybrid offspring that appear to have overstated traits when compared to the parental line.
Transgressive segregation may be a major source of novel adaptations in hybrids.[2]
There are many causes of transgressive segregation in hybrids such as: recombination of additive alleles, an elevated mutation rate, reduced developmental stability, epistatic effects between alleles, or overdominance caused by heterozygosity at specific loci or chromosome number variation.[2]
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