page_title: Invasion genetics
section_title: Genetic consequences of range expansion
hierarchical_section_title: Invasion genetics / Evolution during biological invasions / Genetic consequences of range expansion
caption_attribution_description: English: Flowering purple loosestrife (Lythrum salicaria), Concord, Massachusetts, USA
context_page_description: Invasion genetics is the area of study within biology that examines evolutionary processes in the context of biological invasions. Invasion genetics considers how genetic and demographic factors affect the success of a species introduced outside of its native range, and how the mechanisms of evolution, such as natural selection, mutation, and genetic drift, operate in these populations. Researchers exploring these questions draw upon theory and approaches from a range of biological disciplines, including population genetics, evolutionary ecology, population biology, and phylogeography.
  Invasion genetics, due to its focus on the biology of introduced species, is useful for identifying potential invasive species and developing practices for managing biological invasions. It is distinguished from the broader study of invasive species because it is less directly concerned with the impacts of biological invasions, such as environmental or economic harm. In addition to applications for invasive species management, insights gained from invasion genetics also contribute to a broader understanding of evolutionary processes such as genetic drift and adaptive evolution.
context_section_description: Range expansion is the process by which an organism spreads and establishes new populations across a geographic scale, so it is part of a biological invasion. During a range expansion, there exists an expanding wave front, where rapidly-growing populations are established by a relatively small number of individuals. Under these demographic conditions, the phenomenon of gene surfing can lead to the accumulation of deleterious mutations. This reduces the fitness of individuals at the wave front, and is described as an expansion load (see also: mutation load). These mutations can limit the rate of range expansion and, in the absence of effective recombination and natural selection which would remove such mutations, can have severe and persisting negative effects on populations.
caption: The spread of purple loosestrife, an invasive species in North America, is believed to have been facilitated by adaptive evolution.[21]
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