Also found in: Medical, Wikipedia.
Related to introgression: hybrid swarm, reticulate evolution, backcrossing


The movement or spread of alleles of one species into the gene pool of another through repeated backcrossing of interspecific hybrids with members of one of the parental species.

[From Latin intrōgressus, past participle of intrōgredī, to step in : intrō-, intro- + gradī, to step; see ghredh- in Indo-European roots.]

in′tro·gres′sive (-grĕs′ĭv) adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(Genetics) the introduction of genes from the gene pool of one species into that of another during hybridization
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
References in periodicals archive ?
It is free-ranging and subject to natural selection factors such as predation and competition, while representing a large source of unique genetic variation, with no evidence of introgression from domestic cattle.
haematobium-bovis hybrids on the Mediterranean island of Corsica (4) demonstrates the public health impact of such genetic introgression.
This finding would explain that the hybrid found this summer in the caves of Denisova -- the offspring of a Neanderthal mother and a Denisovan father -- was not an isolated case, but rather was part of a more general introgression process.
Gene flow from taurine cattle into Asian zebu populations has been suggested as an unusual pattern of introgression (Namikawa 1981; Namikawa et al., 1984, 1995; Amano et al., 1994; Kawamoto et al., 1992; Tu et al., 2000; Kikkawa et al., 2003; Cai et al., 2007, 2010).
Being the major entry point of cattle to Africa, the genetic landscape of the current cattle populations in Ethiopia could have been shaped by several introductions of zebu cattle and introgression of the taurine from the Near-East [7].
1998, Mallet 2005, Descimon and Mallet 2009), and even limited fertility provides the possibility for introgression that can have important consequences for species interactions.
Moreover, the feral introgression of the cultured into the wild as a result of escapee fishes has a great tendency of eroding the genetic diversity of the wild, especially if the genetic composition of the cultured population had not been properly managed [16].
group edulis members have been put aside, and most research focus on describing the distribution of different forms, hybridization and introgression, and mechanisms maintaining the integrity of species despite hybridization.
A risk assessment of Atlantic salmon indicates that many locations in Norway are at moderate or high risk of genetic introgression from farmed salmon (Taranger et al., 2015).
Controversy has surrounded the setting of appropriate conservation policies to deal with hybridisation and introgression (genetic admixture resulting from backcrossing with one of the parent species).
"Overall, our results paint a complex first picture of the genomic impact of Neanderthal introgression in the Western Asian populations," the study says.