Genetics is the study of genes, variation and inheritance. Genes drive adaptive changes, resulting from genotypic variation, that a species exhibits during natural selection. This variation creates species diversity, which is threatened by many ecological problems. These may include invasive species, hybridisation, patchiness, inbreeding and disease, to name a few. The study of genetics enables the identification of the most effective conservation approaches for different species. The data provided can ensure that resources are directed appropriately, both spatially and temporally within the species lifecycle.
Genetics is used in phylogeography to study species distribution and genotypic diversity variations with geography. This helps distinguish between native and non-native populations, the latter of which may have an invasive species potential. Phylogeography can identify the source population and invasion route of an invasive species. Understanding where the invasive species come from allows the design and implementation of preventative measures, such as quarantine strategies or biological control agents. These measures protect the native species, preserving biodiversity.
Studying a migratory species’ genes can identify their migration routes too to ensure the removal of barriers and protect the migration path, this will in turn allow them to breed increasing variation and avoiding an inbreeding depression, which maintains a population’s fitness. This genetic data enables conservationists to support the natural maintenance of genetic variation.
Genetics can also help to accurately identify species, which helps to detect hybridisation. Hybrids are the offspring of two different species, who cannot reproduce with the parent species. Hybrids are frequently more invasive than the original native species and their prolific behaviour can have major impacts on the ecosystem. Like invasive species, they often consume resources faster and more efficiently than the native species, resulting in rapid population size increases. Hybrids, therefore, reduce the diversity of the organisms in the area, as they become the dominant species. Genetic analysis of the proportion of species-specific bands identifies hybrids and indicates where resources need directing to conserve the native species. It also enables the early eradication of hybrids, reducing ecosystem destruction.
Snow-Capped Manakin (Left) And Opal-Crowned Manakin (Right) Mated To Produce Golden-Crowned Manakin (Center) Manakin Hybrid Birds.
Genetics also helps identify distinct new species that may be morphologically indistinguishable from other species, these are called cryptic species. Without relying on the use of molecular markers in their genes, two cryptic species may be misidentified as a single “species”. When previously thought of as a single “species”, a group of organisms may not be considered threatened. However, if found to contain multiple cryptic species, then each of these populations will be lower and may now require conservation. Accurate species identification is therefore essential as it allows an accurate population size to be determined, to enable the construction of conservation activities.
The identification of cryptic species through genetic analysis proved useful in the study of the giraffe (Giraffa camelopardalis). The giraffe was previously thought to be a single species, with nine commonly accepted subspecies. However, studying their genetics in 2016 has now identified reproductive isolation between four genetically distinct species. Giraffes are highly mobile animals so a lack of gene flow, between the newly defined four species, was unexpected. As giraffe populations and habitats are in decline due to human-induced threats, understanding their underestimated genetic complexity is essential for targeting future conservation efforts. For example, captive breeding programmes now sequence individuals’ genomes to pair up giraffes of the same species to produce pedigree offspring. These offspring are better able to sustain genetic health over many generations in captivity.
Whilst genetics now contributes frequently to identifying cryptic species, previously this technology was not available. Instead, in 1993 a study of Pipistrelle bats (Pipistrellus pipistrellus) found that there were two distinct bimodal echolocation frequencies emitted by this species. It was therefore hypothesised that Pipistrelle bats were two cryptic species. Whilst this hypothesis was widely accepted by the scientific community it wasn’t until 2001 that the use of mitochondrial DNA sequences identified two divergent and distinct species. These findings correlated to the acoustic analysis of the 1993 study and provided definitive proof to partition the cryptic species into Pipistrellus pipistrellus and Pipistrellus pygmaeus.
Both species are currently protected by the UK through the Wildlife and Countryside Act, 1981 and throughout the EU under the European Habitats Directive, Annex IV (The Wildlife Trusts, 2020). This enforces firm protection rights throughout their natural range in the EU. There are protected areas for both species and bat-friendly construction practices must be adhered to (Hutson et al., 2008). Without studying genetics these bats would not receive these species-specific protections.
Some final thoughts…
In summary, whether genetics are studied to identify hybrids, invasive or cryptic species, migration routes or rates, the data enables the most effective conservation approach to be designed and implemented. Most ecological problems require solutions that increase population size and genetic diversity. Without the contribution of genetics, national and international protection laws could not exist. Without the knowledge of what you are protecting, you cannot protect it. You cannot increase population size and genetic diversity without the study of genetics. Therefore, genetics is arguably the greatest tool in the modern era to understand and solve ecological problems.
Jones, G. and Van Parijs, S., (1993). Bimodal echolocation in pipistrelle bats: are cryptic species present? Proceedings of the Royal Society of London. Series B: Biological Sciences, 251(1331), pp.119-125.
Fennessy, J., Bidon, T., Reuss, F., Kumar, V., Elkan, P., Nilsson, M. A., Vamberger, M., Fritz, U., & Janke, A. (2016). Multi-locus Analyses Reveal Four Giraffe Species Instead of One. Current biology, 26(18), pp.2543-2549.
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