The marsupial mole, a creature as enigmatic as it is fascinating, glides beneath the sands of remote Australian deserts as if swimming in an ocean of dust. This mammal, almost blind and perfectly adapted to underground life, seems to have suffered a drastic decline in their population approximately 70,000 years agoprobably due to climate changes that altered their habitat.
A recent analysis, published this January 1 in the magazine Science Advancesoffers new clues about the evolutionary history and unique adaptations of this species. By studying its DNA, researchers have discovered that the marsupial mole is most closely related to bandicoots and bilbies, despite its striking physical similarity to placental moles, the result of a remarkable evolutionary convergence – a phenomenon in which organisms from different lineages Evolutionary organisms develop similar characteristics because they face similar environmental conditions or functional challenges, although they do not share a recent common ancestor that possesses those traits.
The study also identified genetic adaptations that explain their ability to survive in extreme conditions, such as the progressive loss of eye function—an adaptation to life underground—and adjustments to tolerate low-oxygen environments. These findings not only shed light on the evolution of this elusive mammal, but also highlight the historical impacts of climate and environmental pressures on its survival.
“Our findings reveal a marked decline in the effective population size of marsupial moles, probably preceding the arrival of humans in regions close to their distribution, and possibly linked to periods of climate change. Analysis of loss of ocular function shows a structured order in genetic loss of function, starting with the lens, followed by cone cells, and finally rod cells. Finally, we identified genetic changes that suggest adaptation to low-oxygen environments and the evolution of partially descended testes,” says the Science Advances study.
Marsupial moles are perhaps Australia’s strangest mammals. Known as “itjaritjari” by the indigenous Aṉangu people, these marsupial moles live in the deep deserts of Australia and make their way not by digging permanent tunnels but by “swimming” through loose sands using specialized forelimbs. This lifestyle is so vital to their existence that they have had to adapt in remarkable ways.
They are almost blind, with only vestigial eyes under the skin of their face and lack a scrotum, keeping their testicles in the abdomen. Like kangaroos, marsupial moles have a pouch, although it is upside down, presumably so that sand does not accumulate in it as the mole swims forward through the sand.
Even breathing is a challenge underground, so marsupial moles have also had to evolve to survive in low-oxygen conditions. Incredibly, many of these adaptations are shared with the “true” moles found in Africa, Eurasia, and North America, representing a striking example of convergent evolution.
By extracting DNA from a tissue sample, the team of researchers mapped nearly all of the chemical “letters” that record its evolutionary past and lay out instructions for producing its most distinctive traits. The scientists then used this genome to compare the marsupial mole’s genes with those of its distant, above-ground relatives.
“By examining eye genes shared by all mammals, we showed that the degeneration of the marsupial mole’s eyes occurred in stages: first the genes important for the lens disappeared, followed by the ‘rods and cones’, the cells sensitive to light. light found in the retina. We also showed that marsupial moles have an extra gene for hemoglobin, the protein that transports oxygen throughout the body in red blood cells and that a key gene in the testicular offspring, RXFP2, is “broken” in this species, which gives us an explanation for its internal testes,” explain the researchers from the University of Melbourne.
#DNA #reveals #evolution #Australias #enigmatic #cryptic #mammal #marsupial #mole