Summary
The movement of alleles between populations through migration and interbreeding, reducing differences between them.
In depth
Migrants carry alleles between populations, making them more similar and countering divergence by selection or drift. Even low migration of a few individuals per generation can prevent differentiation.
Barriers to gene flow promote speciation.
Gene flow can bring new alleles into a population (such as pesticide resistance spreading between insect populations) or dilute local adaptation. In crops, pollen from genetically modified plants can transfer genes to wild relatives, a concern for regulators.
Human history shows large flows: studies of ancient DNA reveal admixture with Neanderthals and Denisovans, and European, Asian and African ancestry vary gradually, with no sharp boundaries. Barriers such as mountains, oceans and behaviour reduce it and enable speciation.
Remember: gene flow tends to make populations more similar, while drift and selection tend to make them different.
Frequently asked questions
What is Gene Flow?
The movement of alleles between populations through migration and interbreeding, reducing differences between them.
Which area of biology covers Gene Flow, and how advanced is it?
Gene Flow is one of the 54 topics in Genetics. It is rated Advanced, so it suits learners who want specialist depth. Related topics in this area include Population Genetics Models, Genetic Drift, Genetic Variation.
Can you give an example of Gene Flow?
Pollen carried by wind can spread transgenes from crops into wild relatives.
What should I learn before Gene Flow?
Work through the Beginner topics in Genetics first, such as Heredity, Gene, Allele, then return to Gene Flow. Advanced topics assume the Intermediate vocabulary.
What topics are related to Gene Flow?
The closest topics to Gene Flow are Population Genetics Models, Genetic Drift, Genetic Variation, Gene Pool. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Gene Flow?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Gene Flow. To practise the whole of Genetics, use the Genetics quiz.
How is Gene Flow different from Population Genetics Models?
Gene Flow: The movement of alleles between populations through migration and interbreeding, reducing differences between them. Population Genetics Models: Mathematical models using selection, mutation, drift and migration to predict allele frequency change. Read both side by side and note what each one explains.
How should I study Gene Flow step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Population Genetics Models and explain the difference aloud. Finally, take the Genetics quiz and come back to this page for any question you miss.