MODERN-DAY MUTANTS
Mutations have allowed these species to adapt and survive
MRSA Staphylococcus aureus
As single-celled organisms, each time bacteria create a copy of themselves through cellular division they run the risk of mutation. In 20 minutes or less, bacteria can double their population. When a mutation occurs it quickly becomes the norm, such as in methicillin-resistant Staphylococcus aureus (MRSA): mutations have given it the ability to resist the effects of antibiotics.
EUROPEAN HOUSE MOUSE Mus musculus
Warfarin is a blood thinner used in pest control. The poison works by reducing vitamin K production, which helps the body form blood clots – an important process that prevents excess bleeding. A mutation in a gene called VKORC1 allows certain mice to produce more vitamin K and combat the blood-thinning ability of warfarin.
TABLE CORAL Acropora
Warming temperatures cause coral species to ‘bleach’, where they lose their vital algae and die. Research has shown that table corals have mutated to adapt to warmer waters. Heat-tolerant corals like these are more likely to survive in the face of a warmer climate and may evolve into the dominant type of coral in our oceans.
GREEN ANOLE Anolis carolinensis
In only 20 generations, green anole lizards have rapidly evolved to best a group of invasive brown anoles in the US. Within the span of 15 years, these tree-dwelling lizards have evolved larger toepads with more sticky scales that allow them to reach heights that their invasive competitors are unable to access.
PEPPERED MOTH Biston betularia
These moths are naturally speckled white and black. During the rise of the Industrial Revolution, they were able to adapt and survive predation thanks to a mutation that emerged around 1819. It made these moths darker – almost completely black – allowing them to blend in on urban tree trunks that had been coated in soot.
and technological innovators that we are today. Over millennia, both small and large mutations to the human genome have propelled our evolution and created the modern human, from the shedding of our body hair to the development of large brains. One example of a recent human mutation happened between 6,000 and 10,000 years ago, affecting a gene called OCA2 that halted the production of the melanin pigment in the iris that colours the eyes brown, diluting eyes to a shade of blue.
One of the ways humans have evolved – and continue to evolve – relates to our diet. Humans are one of the only mammals that drink milk after infancy. The ability to digest dairy in adulthood is down to a group of genes that allow our bodies to break down the sugar in milk, lactose. In other mammals the genes that codes for proteins that can digest lactose typically switch off after infancy, but a mutation in some humans stops that from happening. “We know there are four independent mutations that we see in various human populations, and they sit in the promotion of this gene,” says Laurence Hurst, professor of evolutionary genetics at the University of Bath. “Rather than it being switched off, it gets switched back on again.” Over the last 8,000 years, this has led to around 90 per cent of Northwestern Europeans having the ability to digest lactose. It’s often thought that humans have jumped off the evolutionary train and have reached their final biological destination, likely due to advancements in medicine reducing the need for natural selection. However, this isn’t the case. Adaptive mutations are still prevalent in our species, shaping the way humans evolve.