Researchers worry that the most isolated vertebrates on earth will soon be extinct.
Nevada is home to the only known population of pupfish in America for more than 10,000 years. Devils HoleThis underground oasis is located in Death Valley National Park’s desert borders.
The limited habitat is a 152-meter-deep (500 feet) cave, making it the smallest known abode for any creature with a backbone – and the extreme conditions are taking their genetic toll.
Biologists at the University of California Berkeley have sequenced the genome of eight Devils Hole-based pupfish and found that they have interbreeded to the extent that each fish has about 58 per cent of its genome.
“High levels are associated with higher levels of inbreeding and the inbreeding of the Devils Hole puppyfish is equal or greater than levels reported so far for other isolated natural populations like the Isle Royale wolves of Michigan, Indian Tigers and mountain gorillas of Africa.” SaysChristopher Martin, UC Berkeley integrative biologist, and lead researcher
This is similar to the shockingly high levels of genome cross-pollination in endangered species like Florida panthers.Puma concolorIsle Royale Wolf (Canis lupus), and mountain gorillas (Gorilla beringei), all of which are suffering from extreme population declines.
Researchers at Berkeley found that only 10 to 30% of the genomes of pupfish are identical when compared to those of other species. The Devils Hole clearly has exacerbated this situation.
For example, it is possible that Devils Hole pupfish might be accumulating genetic variants which could make it more difficult for them to survive.
Devils Hole has a shortage of oxygen and food. However, the genome sequences have revealed that certain pupfish alleles which are closely related to reproduction and survival in low oxygen conditions may have been lost or deleted.
The good news is that these mutations have been around for quite some time.
Researchers sequenced the genome from a Devils Hole preserved pupfish taken from a museum collection to find evidence of high levels of inbreeding, at least since 1980.
It was a long time before the population declined to a handful of individuals in 2007 as well as again in 2013. The Devils Hole pupfish population is now estimated at 175. Scientists are considering them Critically endangeredNo one knows why they are disappearing. They now want to find out if any genes are responsible.
“Part of the mystery about these declines is if they could be due to the genetic state of the population,” This explains Martin.
“Maybe because of harmful mutations that have been fixed by the small population, the declines may be explained.”
Groundwater pumping and human activity aren’t likely to help. Natural events like earthquakes can sometimes help. Shake up underground refuge: Waves that reach Devils Hole are big enough to squash the eggs of pupfish or rip off the algae from the cavern’s sunlit shelf.
These are the only nutrients that the pupfish have, so they can be very dangerous.
Rising temperatures could also be a possibility. If Climate ChangeHeats Devils Hole to above 33 degrees Celsius (91.4 Fahrenheit) and the water temperature rises, resident pupfish might not be able reproduce as fast or efficiently.
Because genetic variation allows future generations to adapt to changing environments, it is believed to be vital for animal survival.
Not all mutations are good, and some can drag along with high levels of inbreeding.
Biologists are hoping to analyze the genomes from small populations such as Devils Hole to understand how evolutionary dynamics work and what can be done for endangered species.
A mutation that reduces the ability of Devils Hole puppies to survive in low oxygen may be a sign that technology is possible. CRISPRResearchers could use this information to delete the allele from their genome or to restore genes that were lost.
Researchers discovered 15 genes missing from the Devils Hole puppyfish’s genome.
Although it is controversial, this idea is being investigated by conservationists as well as biologists.
“Our future work will be to look at what these deletions do,” Says Martin.
“Do they increase hypoxia tolerance? Do they reduce hypoxia tolerance? These scenarios are both plausible, I believe.”
Scientists can make better decisions about how to save the pupfish once they know more about Devils Hole.
The study was published by Proceedings of the Royal Society.
