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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Assisted gene flow | 1/3 | https://en.wikipedia.org/wiki/Assisted_gene_flow | reference | science, encyclopedia | 2026-05-05T14:17:36.560692+00:00 | kb-cron |
Assisted gene flow (AGF) is a conservation management strategy that moves individuals or gametes between populations of plant or animal species within the species's existing range. This strategy responds to the effects of climate change by facilitating adaptation to projected local climate conditions. For example, an AGF management plan may move individuals from a source population (or populations) living in a warm region to a target population in a colder, but rapidly warming region. Not to be confused with assisted migration, AGF is a strategy focused on gene flow between existing populations rather than an introduction of individuals to new or restored habitat. AGF is also similar to genetic rescue, a conservation technique intended to prevent species extinction; however, AGF emphasizes long-term conservation and has broader applications. For species that experience local adaptation to historical climate conditions and have populations with genetic compatibility, AGF can be an effective climate change mitigation strategy to help maintain genetic fitness in threatened species.
== History == Although the term "assisted gene flow" was first used in a published article in 2013 by Aitken & Whitlock, the concept was recognized as early as 1992 by Ledig & Kitzmiller who wrote about reforestation under the threat of climate change. In this publication Ledig & Kitzmiller suggested that planting programs should consider sourcing seed from further south or lower elevations. The term "targeted gene flow" has also been used to describe the movement of individuals with desired genetic traits into target populations as a conservation strategy. Research on AGF as a conservation strategy, including the analysis of trees and shrubs, herbaceous flowers, reef corals, as well as terrestrial animal species, has shown promising results and revealed potential genetic risks.
== Applications and benefits == The ultimate benefit of AGF is the protection of species' health and productivity, including economically important and keystone species, to conserve biodiversity in the face of climate change. Threatened species are at risk of maladaptation due to the rate of natural adaptation falling behind the rapid rate of environmental change, which causes loss of ecosystem function as well as the loss of resources and ecosystem services they provide. AGF can help introduce genotypes that are pre-adapted to new local climates or increase the frequency of climate adapted genotypes that already exist within the population, strengthening a species evolutionary potential and persistence through environmental change.
=== Accelerating gene flow === In stable environmental conditions, natural selection drives adaptation to the local environment; however, as environmental conditions change over time, species can adapt to new conditions by exhibiting natural processes like gene flow. Gene flow is simply the transfer of genes between populations of the same species. Natural gene flow tends to exhibit a leptokurtic distribution, as opposed to a normal distribution, in which more individuals and gametes distribute a shorter distance from the source population than further. As anthropogenic activity continues to increase the rate of climate change, adaptation by way of these natural processes may not be able to keep up. Additionally, habitat fragmentation caused by human development also prevents natural adaptation by inhibiting gene flow. AGF can direct gene flow in a targeted direction at any desired distance, working to overcome these environmental barriers by speeding up the natural adaptive process.
=== Assisted gene flow vs. genetic rescue === Genetic rescue is a conservation strategy that targets small, isolated populations that have lost significant genetic diversity and are under threat of extinction. Similar to AGF, genetic rescue introduces new individuals into the target population with the goal of restoring genetic diversity and increasing overall fitness. The two methods deviate in their ultimate goal; Genetic rescue attempts to alleviate inbreeding depression to bolster fitness and promote population growth, while AGF is more directional, aiming to promote genetic adaptation to future climate conditions. While genetic rescue may be considered a form of AGF, it is a short-term conservation solution focused on reducing extinction risk in small populations. Genetic rescue efforts tend to source individuals from populations with similar environmental climates as the target population. AGF focuses on longer term conservation, sourcing individuals from populations that are adapted to different climate conditions that match future conditions facing the target population. AGF has applications to a greater range of potential recipient populations. In small, threatened populations, AGF is identical to genetic rescue, reducing inbreeding depression and increasing genetic diversity. AGF also assists larger or more fit populations, such as foundation species, that have greater evolutionary potential, but may experience increased stress as climates shift faster than natural adaptation can occur.
=== Assisted gene flow as assisted migration === Assisted migration is another conservation strategy which involves the anthropogenic movement of species to more suitable habitats in response to changing environmental conditions. AGF can be considered a type of assisted migration which focuses on the movement of individuals or populations of a species to areas within its existing range, while assisted migration is broader, including the introduction of a species to a new geographic location beyond its current range. Due to the nature of AGF maintaining the species' existing range, the ecological risks of moving individuals or gametes are much lower than introductions to new areas.