March 03, 2017
The last existed woolly mammoths that walk around planet Earth were so wrecked with genetic disease that they ostracized company, lost their sense of smell, and had a weird shiny coat.
This has been concluded by the scientists who have analyzed ancient DNA of the extinct animals for mutations. The findings suggest that mammoths perished post their DNA became riddled with several errors.
This knowledge can enlighten the conservation efforts for several living animals.
At present, there are less than 100 Asiatic cheetahs remaining in the wild, whereas the mountain gorilla population is approximated to be around 300. These numbers are quite similar to the last of the woolly mammoths that ever lived on Wrangel Island in the Arctic Ocean nearly 4,000 years ago.
From the University of California, Dr Rebekah Rogers, the leading member of the research said that the mammoths’ genomes were falling apart right before they went extinct", this incidence she describes as "first case of genomic meltdown in a single species".
She further explained, "You had this last refuge of mammoths after everything has gone extinct on the mainland."
"The mathematical theories that have been developed said that they should accumulate bad mutations because natural selection should become very inefficient."
The researchers canvassed genetic mutations discovered in the ancient DNA of a mammoth from 4,000 years ago. This was later confirmed with a mammoth which lived nearly 45,000 years ago, that is when the animal roamed entirely across North America and Siberia.
Woolly mammoths were earlier common in Siberia as well as North America. They were forced towards extinction by environmental factors and potentially because of human hunting nearly 10,000 years ago.
Dr Rogers mentioned that, "There was this huge excess of what looked like bad mutations in the genome of the mammoth from this island."
"We found these bad mutations were accumulating in the mammoth genome right before they went extinct."
The facts and data of these last extinct mammoths might help present species on the brink of extinction like mountain gorilla, panda and Indian elephant. The conclusion from the wooly mammoth is such that when the total numbers go down a specific level, the population’s genetic health might be beyond saving.
Dr Rogers said, "When you have these small populations for an extended period of time they can go into genomic meltdown, just like what we saw in the mammoth.”
"So if you can prevent these organisms ever being threatened or endangered then that will do a lot more to help prevent this type of genomic meltdown compared to if you have a small population and then bring it back up to larger numbers because it will still bear those signatures of this genomic meltdown."
Research scientists believe that genetic mutations might have resulted in the shiny satin-like coating on the woolly mammoths. The same mutations might have also resulted to a loss of olfactory receptors accountable for the sense of smell.
Professor of evolutionary genetics at the Swedish Museum of Natural History, Love Dalen is the leading member of the scientist team which initially published DNA sequences of the mammoths.
He said, "They find that there are many deletions, big chunks of the genome that are missing, some of which even affected functional genes. This is a very novel result. If this holds up when more mammoth genomes, as well as genomes from other species, are analyzed, it will have very important implications for conservation biology."